Science Demonstrations

Methods:
1) Add food coloring into the water being used so it can be seen better.
2) Pour the colored water into the container.
3) Slowly pour in the oil into the container containing the water.
4) Let settle for a few seconds so the oil can create a visible layer.

Conclusions:
Water stays at the bottom while the oil floats on top of the water creating two separate layers of liquid in the container.
Water has a higher density than oil.

Materials:  2 liter soda bottle (empty) and its cap
Small container such as large water glass or bowl
Glass medicine dropper (one that sinks in water) ? or- plastic drinking straws, a paper clip, and some modeling clay

Procedure: Take the empty soda bottle and fill it completely with water. Fill the water glass with water and place the medicine dropper in the glass. Get some water inside the dropper by squeezing the rubber bulb while the end is in the water. You want to get the dropper to just barely float upright in the water. Once you’ve done this, place the dropper in the soda bottle and screw on the cap tightly. Don’t allow much air to be between the top of the bottle and the cap. Gently squeeze the bottle. As you squeeze, the dropper will dive (sink) to the bottom of the bottle. If you stop squeezing, the dropper floats back to the top.

If you can’t find a medicine dropper, you can duplicate the same effect by bending half of a plastic drinking straw in half and securing it with a paper clip. Put a small amount of modeling clay on the bottom end of the straw and, like the medicine dropper, just get it to barely bloat on the surface of the water in the water glass.

Explanation:
This experiment demonstrates the property of buoyancy. An object is buoyant in water due to the amount of water it displaces or ‘pushes aside’. If the weight of water that is displaced by an object in water exceeds the weight of the object, then the object will float. With the Cartesian Diver, the buoyancy is equal to the weight of the water that is displaced by the medicine dropper and the air bubble in the dropper. When the bottle is squeezed, the air bubble becomes smaller and displaces less water so buoyancy is less and weight pulls the dropper to the bottom of the bottle. When it is released, the bubble becomes large again and buoyancy pushes the diver to the top.

Resources:
http://www.geocities.com/capecanaveral/3582/cart1.html
http://www.fatlion.com/science/cartesian.html

Purpose: To determine the effects of salt(sodium chloride) on water density
Materials: 2 500 ml beakers, 15 teaspoons of Kosher salt, 2 eggs, 800 ml of water

Procedures:
1. Mix 15 teaspoons of Kosher salt and 400 mls. of water in a beaker (2T in a glass) -- try out the proportions before doing it as a demo in class. It takes much more salt than you expect it to need!
2. Put 400 mls. of water in other beaker.
3. Place an egg in the beaker with the pure water and observe.
4. Place an egg in the beaker with the saltwater and observe.

Observations:1. The egg in the beaker with the pure water will sink because the water is less dense than the egg. 2. The egg in the beaker with the salt water will float because the water is more dense than the egg.

Questions:
1. How does salt change the density of water?
2. Do other salts and/or powdered solids have the same effect on the density of water?

Note: Kosher salt will work better for this demonstration as it leaves the water more clear for observing the egg.

Carefully place the egg in a glass half full of water. It will sink.  Stir salt into the water, one teaspoonful at a time. The egg will graduallyfloat up as you add more salt.  When the egg is floating at the surface, carefully add more water to nearly fill the glass. Dribble it slowly over a spoon held against the side of the glass, so that the fresh water doesn't mix with the salt water. You will end up with the egg floating on the boundary in between the fresh and salt water layers.

The weight of fresh water displaced by the egg weighs less than the egg, so the egg will not float on fresh water. The weight of the salt water displaced by the egg, however, is the same as the weight of the egg, and the egg flats on the salt water. Fresh water will float on salt water aslong as the two don't get mixed together.

Alternative Description:  Carefully place an uncooked egg (still in its shell) in a dish of water. Be sure the water is deep enough to cover the egg. Does the egg float or sink? Remove the egg and add salt to the water. Stir the solution and keep adding salt until the water seems saturated. Place the same egg in the salt water. Does the egg float or sink?

Alternative Demo Ideas: . Mix well. (To be sure this experiment would work before the class, I made VERY sure the water was salty. I added 3 tablespoons of salt to each cup of water, and shook the saltwater hard in bottles. Then I poured the "pre-made" saltwater into the container.)
Carefully crack open an egg and gently set it on the surface of the tap water.
Now crack open the other egg and set it on the salty water.
Explanation: The egg sinks in freshwater, but floats on saltwater. This is because there is more "stuff" in saltwater than there is in the same amount of freshwater -- meaning, saltwater has a greater density. Saltwater can hold up the weight of the egg, while freshwater doesn't have enough "stuff" in it to support the same weight.

What to do:
1. Add 500 mL of water to one beaker.
2. Add 500 mL of isopropyl alcohol to the other beaker.
3. Add same amount of ice to each beaker.  Do the ice pieces float or sink?

Does the ice sink to the bottom or float on top?
The ice floats in water because the density of ice is less than the density of water.  The ice sinks in the alcohol because the density of ice is greater than the density of liquid isopropyl alcohol.

At home I peeled one lemon and kept a whole one, then put them in a tank together for the demo.  The peeled lemon must be peeled really well. An orange will also show this!

Procedure:
1. Fill a large beaker with water.
2. Form clay into a ball.
3. Place the clay and marbles in water and watch them sink.
4. Remove clay and marbles from water.
5. Shape clay into boat.
6. Set clay on water and watch it float.
7. Place 3 marbles on clay boat as cargo.

Explanation: Even though a ship is huge and weighs a lot, it floats. Whereas a small and light marble sinks. The weight of an object is not a factor. The amount of water an object "displaces" or pushes aside determines if it will float.
Taken from the book: "101 Great Science Experiments"  by Neil Ardley

I will use one egg, 2 clear bottles, water, and some sugar or salt to increase the density of the water.  The egg should sink in the plain water
and float in the saturated salt (or sugar) water.

Objective: to demonstration Archimedes' relation
Archimedes' relation states: A fluid acts on a foreign body immersed in it with a net force that is vertically upward and equal in magnitude to the weight of the fluid displaced by the body. (This upward force is called the buoyant force.)

Mathematical equation:   Force = Density x volume
Equipment and material required:
1. Two 250 ml beaker
2. Stirring rod
3. Two eggs
4. 1/2 lb of sugar
5. 500 ml of tap water

Procedure:
1. Fill the beakers with 200 ml of tap water
2. In one of beaker, add 1/2 lb of sugar. Stir until the sugar totally dissolves.
3. Put the eggs into the two beakers and observe.
4. The egg in the first beaker should sink to the bottom. The egg,in the second beaker with sugar water, floats to the surface.
5. In the second beaker the density of solution is higher because sugar increased the density of water. The egg displace the sugar/water solution;the buoyant force became large and egg starts to float.

What to do: Crumple the foil into a tight ball and poke a V-shaped hole through the ball. Pull the string through the hole using tweezers if necessary.

Premise: If the string is kept loose, the ball moves freely up and down on the string. However, if the string is pulled tight, friction between the string and the
point of the V causes the ball to not move up and down. Relax the string again and the ball slides up and down.

Note: If the ball still moves up and down when you tighten the string, then the hole must be made more V-shaped.

Procedures:
1) Mix about 10 teaspoons of salt into half a glass of water.
2) Place an egg into the salt water.  Notice that it will float near the surface of the water.
3) Place an egg in a half glass of clean water (no salt).  Notice that it will sink to the bottom.
4) In a third glass, add clean water to salt water.  Don’t let the two waters mix.
5) Gently place the egg into the water.  Notice that the egg will float on the salt water; therefore, the egg is suspended in the middle of the glass.

Explanation:
1) The egg floats in salt water because the egg is LESS dense than salt water.
2) The egg sinks in clean water because the egg is DENSER than salt water.
3) Because of the two reasonings above, that is why the egg is suspended in the middle of the glass (salt water and clean water).

Procedure
1. Pour about five inches of water into the jar
2. Add enough oil in the jar so once separated out, there will be an inch to two inch    layer of oil on the water.
3. add one drop of food coloring
4. pour salt on top of the drop of food coloring
5. to continue the reaction by adding more salt

Materials:
1. 50ml Diluted blueberry juice
2. Vinegar
3. Ammonia
4. 3 100ml beakers

Procedure: Add a small amount of ammonia to the diluted juice and observe a color change. Then add vinegar and the solution will turn back to a blue color.

Principle: When the base, ammonia, is added to the juice it turns deep green indicating the presence of an acid. Because blueberry juice is naturally acidic the color does not change when an acid, vinegar, is added to it, but it will turn the green solution back to acidic and blue-ish.
[NOTE: this works with other purple juices -- red cabbage, grape juice, cranberry juice. It is the anthocyanin which is pH sensitive]

Materials:
Hydrogen Peroxide 30% 25 ml Food color A few drops
Potassium Iodide (Catalyst) About 2 grs Dish washer liquid About 3ml
One Graduated Cylinder 100ml

Explanation: Food color is for making experiment more interesting, and dish soap makes release of gas more visible for students. It is better we do this experiment in the sink or in a big plastic container.

Demo: we add food color and dish soap first , then Hydrogen Peroxide and Catalyst together . As Hydrogen Peroxide decomposes , according to this reaction (2 H2O2----> 2 H2O + O2 + Q ) water will vaporizes and Oxygen gas flows bubbles of soap out of Graduated Cylinder .

Application: 1 - students will experiment a Decomposition Reaction
2 - An exothermic Reaction
3 - A reaction that produces gas
Time: About 2-3 minutes

The purpose of this lab is to demonstrate surfactance of a liquid. First, place the bowl on a level surface and fill it with water.  Next, liberally deposit pepper all over the surface of the water.  Once the surface of the water is covered with pepper you are ready for the final step.  NOW BE PREPARED!!  This experiment goes very fast. Add one drop of the soap to the bowl of pepper, directly in the middle.  What will happen is the pepper should immediately be dispursed to the outside of the bowl.  The reason for this is that the soap is a surfactant.  It instantly distributes itself over the surface of the water in a fine sheet, and as it does this it pushes the small grains of pepper along with it.  This experiment is great for trying to get smaller children to understand the steps of the "Scientific Method".

MATERIALS:
   A small clear glass cup (its diameter is less than 2 inches)
   Paper circles ( cut from a hole puncher)
   A toothpick
   A small dropper
   Tap water

PROCEDURE:
   Fill the glass to three-querter full with tap water.
   Wait until the water surface stands still.
   Use a toothpick, gentle place three or four paper cilcles to the center of the cup.
   For a few seconds, paper circles move towards the glass wall and stick to it.
   Add more water to fill the glass to the edges.
   Use a small dropper to add dropwise until it is overflow the wall edges.
   Wait for the water surface quite again.
   Carefully drop three of four paper circles to the center of the cup.
   Use toothpick to push the circles gently and slowly (be carefull, don't force it) toward the wall.
   The circles resist moving to the edges and move back to the center of the cup and stay there.

EXPLANATION:   Water molecules experience two different kinds of intermolecular attractions. The attraction between like molecules (in this demo, the water molecules), called cohesion. The other, which is called adhesion, is the attraction between unlike molecules, such as those in water and in the wall of glass in this experiment.
   In the case of water, adhesion attraction between the water molecules and glass wall is greater than cohesion among water molecules As the cup was not completelty filled with water, there was existing the adhesion attraction between water and the exposing glass wall surface. Therefore, water molecules were pulled toward the walls. (Paper circles moved and stick to the glass wall). Later, as the cup was completely filled with water, which in tur, also covered completely the glass wall surface. As a result, adhesion attraction was eliminated and cohesion was the dominant force that keeps the water molecules from being pulled away(paper circles had the tendency to stay together in the center rather than moving to the glass wall).
(1) Janice VanCleaves, Chemistry for Every Kid, page 48-49

Materials Needed:
A piece of aluminum foil
A clear container
Bottle of dish washing soap
Scissors
Procedure:

1. Cut the aluminum foil into the shape of a powerboat. Just make up a shape.  But keep your boat only about 2 inches wide and about 4 inches long.
2. Gently place the boat into a sink full of clean water (no soap).
3. Squeeze a drop of dishwashing liquid onto the water behind your boat.

What’s happening: The boat moves. The soap breaks up the surface tension in the water behind the aluminum foil. The surface tension pulls the boat forward.

The process is very simple:
The water molecules can be thought of as spheres held together to give a body of liquid by intermolecular forces (hydrogen bonds). The hydrogen bonds between the molecules are strong enough to give the water a "surface tension". When soap molecules are introduced, they squeeze between the water molecule "spheres" increasing the distance between them. With this increased distance the intermolecular forces are weakened and become less efficient in keeping a surface tension.

Pepper Plate - Princess Aryee

Did you realize that there is a miniature version of tug-of-war being played across the water's surface?  One molecule tugs this way.  Another molecule pulls the other way.  But since the tugs occur equally in all directions, they cancel each other out.  A little bit of soap, however, can change the balance!

Materials shallow plate     pepper        water              dishwashing liquid

Exercise:  Clean and rinse a large shallow plate.  Make sure that all soap has been rinsed from its surface.  Fill the plate 3/4 full with cold water.  Let the water stand until it is perfectly still.  Sprinkle some pepper across the surface of the plate.  Add a single drop of dishwashing liquid near the rim of the plate.  What happens?

The Science: The pepper was supported on a layer of surface tension.  Within this layer, molecules of water pulled against each other.  Since they pulled equally in all directions, the layer remained stationary.  The soap that was added to the water broke the surface tension.  Since the forces were no longer active in this region of the plate, the surface tension on the far side of the plate caused the layer to contract.  The pepper, riding atop of this layer, was carried across the urface.

Materials: 2 prisms 1 flashlight
Procedures: Shine the flashlight into one prism at an angle.
Adjust the light angle until a colored spectrum is achieved on a surface. With the colored spectrum achieved from the first prism, take the second prism and place it in front of the first prism as diagramed below.

Hydrophobic vs Hydrophilic forces as observed on grapes - Fred Becerra

Materials
• one peeled grape
• one unpeeled grape
• 7-up soda.
• A cup

The teacher pours non-flat soda into one cup. The two grapes are dropped at the same time. The presence of the hydrophobic skin is observed by seeing the unpeeled grape rise to the top of the cup while the peeled grape remains at the bottom. The reason for the increased altitude for the unpeeled grape is that the skin has hydrophobic interactions to the upward escaping carbon dioxide gas. This experiment can be done at as many student locations the teacher deems necessary as it is very cost effective and very safe for the students to handle.

Procedure
Cut an apple into quarters.  Take one quarter (25%) and cut it in half to represent 12%.  Now take one of those halves and cut it in half to show 6%.  Cut one of those halves in half again to show 3%.  This slice represents all of the fresh water in the world, while the rest of the apple represents the oceans.  The fresh water can be further divided into usable and unusable by cutting the 3% slice into a 1/3 and 2/3 section (1% and 2% respectively).  The 1% slice represents the usable fresh water that is available to all of the organisms on Earth.

On a side note
For this demonstration, it is best to cut the apple into the described sections prior to the demonstration (so that we don’t have to wait while you cut).  However, as soon as an apple is cut and exposed to the air, the surface of the apple turns brown due to oxidation.  Squeezing a few drops of lemon juice on the cut surface of the apple may prevent this.  The ascorbic acid (vitamin C) in the lemon slows down the oxidation process.

Procedure:
Note:Perform this experiment over the sink! Instructions to perform the experiment:
1. Fill the glass half way full with water.
2. Put the card over the top of the glass. Make sure that the card is larger than the mouth of the glass.
3. Put pressure on the card such that no air can get in between the glasses rim and the card. Slowly turn the glass over. Wait a second and remove your hand. The card should remain in place.

What you will need for this experiment:
 Water glass, plastic cup, make sure the mouth is larger or same size as than the bottom.
 Water
 Large container to catch any water spill
 A piece of cardboard, 5"x8" index card or plastic lid.

What to do:
1. Fill the cup to the top with water.
2. Place the lid over the mouth of the cup.
3. Gently hold the cup in one hand and hold the lid in place with the other hand.
4. Over the container, turn the glass upside down with one hand while still holding the lid in place     with the other hand.
5. Once the cup is completely upside down, slowly remove the hand that is holding the lid in place.

Try this experiment with only a half glass of water, or a larger size glass, larger lids, and see if there is any difference between the amount of water used or the sizes used.

Can you figure out why the water stayed inside the glass?

How it works:  The pressure of the water pushing down inside the glass is decreased just enough so that the air pressure underneath the lid pushing up is enough force to hold the water in the glass even though it is upside down.

Materials:
Household drinking glasses (almost any sizes, but the opening should be the Same size or larger than the base)
Cardboard (or other rigid, smooth, flat, lightweight material) in pieces large enough to completely cover the opening of the glasses water

Description: Put a few ounces of water into a small glass. Cover the opening with a piece of cardboard. Make sure that it is completely covered. Holding the cardboard in place, turn the glass and cardboard upside down. Carefully let go of the cardboard. It will stay in place, with the water "stuck" inside of the glass. Repeat with larger glasses or more water if desired.

Fill glass with water as much as you can without spilling. Place lid on top of glass.  Holding the lid in place, invert glass. Slowly let go of lid and wait for gasps of pure amazement.

Explanation: Atmospheric air pressure pushes on objects with 14.7 pounds per square inch (at sea level). This is enough pressure to hold the cardboard in place and the water on top of it (so long as there is an adequate seal formed by the liquid between the lip of the glass and the cardboard, and the weight of the water above does not exceed the weight/area limits).

Applications: May be used in discussions of the atmosphere, the physical properties and behavior of gases.

P.S.-You might want to practice this one over a sink

one large container full of water (pan or bowl)
a small clear cup
a paper towel

Make sure that the cup can fit into the larger container so that it can almost be submersed. Crinkle the paper towel into a ball and stuff it into the cup so that it remains in the bottom of the cup when you turn the cup upside down.  Take the cup with the paper towel inside and turn it upside down.  Slowly push the cup under water.  Go straight down and then straight back up.  The paper towel will remain dry as the air is taking up space.  Be careful to keep the cup straight up and down so as not to release any of the air in the cup.

Materials;
• Jar
• Freezer
• Fire
Procedure;
1-Keep the jar in the freezer for 1-2 days,
2-Take out the jar form the freezer. Try to open it. It is difficult to open because, the value of the top of the jar decreases in the cold,
3- Heat the jar with a candle (20-30sn)
4- Try to open the cover. It is easy to open now. Because the value of the cover increases with the heat.

Premise: Combustion requires oxygen so when you deprive a burning object, such as a candle, the flame will go out.

Materials:
A candle, preferably a large one that every one will be able to see
A glass jar large enough to be inverted over candle
Matches

Procedure:
Light candle
Cover candle with glass jar, making contact with an even surface below
Wait and watch the candle go out

What to do:
Make two holes on opposite sides of the roll in order for the dowel to go through.  Once the dowel is through the roll, blow up one of the balloons and clip its end and then carefully tape it to the end of the roll.  Blow up the second balloon and clip its end and tape it to the other end of the roll.  Make sure the balloon openings are facing opposite of each other.  Once you have arranged the balloons you can either have a helper hold the bottom end of the dowel or place it through the top of a shoe box or any stationary object serving as a stand. Carefully remove the clips from the ends of both balloons and you will see the paper towel roll spin.

Directions Get a copper pipe, a marble, a magnet ball. First let the marble go down the copper pipe and then the magnet ball to show the difference in velocity of each ball.

Scientific Principles:
• States of Matter
• How heat and pressure can effect the states of matter

Materials:
• Pyrex flask – 500ml or larger, with rubber stopper
• Heating unit (Bunsen burner or heat plate)
• Heavy duty safety gloves
• Water
• Ice in strong zip lock bags (2)

Procedure:
• Heat approximately 200 ml of water in flask over heat.  Boil for a couple of minutes.
• Using gloves, take flask off heat, wait 5 seconds and cap with rubber stopper (firmly).
• Turn off heat.
• Place flask on sturdy surface for class to see, using a safety glass is highly recommended.
• Wait for flask to cool enough so it is clearly not boiling anymore from the heat (30 seconds).
• Place bags of ice on the sides of the flask.  As the steam inside cools, a mini-vacuum is created and water will start boiling due to lack of pressure on top of it.
• After demo is over uncap the flask so a strong vacuum doesn’t occur inside the flask.
• Be careful, flask stays hot for awhile.

Materials Dry Ice - Look in the phone book under Dry Ice Clear container with 1 L of water ( make sure the water is at least 3-4 inches form the top of the container) Heavy gloves to handle the dry ice
Procedure Drop dry ice into the water and watch the sublimation. Dry ice has a temperature of -1090F so make sure you are wearing the heavy glove when handling it.
Explanation The water speeds up the sublimation of the dry ice (solid CO2). It causes the water to bubble as the CO2 goes from solid to gas. The gas reaches the top of the water and appears in the form of a thick heavy fog. The CO2 gas is heavier then air so it will fall over the side of the container.

Alternative Description: El Crusher
Materials:  Container for water, soda can, tongs, hot plate, water (cold water for the container for a better effect)

Place the cold water in the container, (adding a little ice to make it even colder is great too) a few
inches is good.  Take a small amount of water and put it in the soda can, enough to cover the bottom.  Place
the soda can on the hot plate and wait for the water to start boiling.  The presence of steam coming out of
the soda can means its ready.  Then take your tongs and grab the soda can and quickly turn it upside-down
and place it in the container with the cold water.  Now just watch "el crusher" take effect.

What happens: When the can is heated the air pressure inside the can is lesser than the air pressure in the cold water. The heated can when placed on cold water will act like a vacuum because the high air pressure in the water will crush the can which has low air pressure.

Additional Teaching Tips:
Applications:
This demonstration can be valuable for many types of classes, not just physics.  A biology class when discussing different animal adaptations to the abyssal zone, a chemistry lecture on the changing stated of water and the effect on pressure, and of course a physics class when talking about pressure.

Safety
If this demonstration were done in front of a class I would recommend (just so the students learn good lab safety) that this be done with goggles a tongs and hair pulled back. Also I would go into how to use a hot plate.

In the Classroom
• The students would be told that there was a small amount of water covering the bottom of the can and that the tub/bucket was filled with water.
• Ask the students to write down their observations before during and after the experiment
• Then ask the students to hypothesize why the can was crushed

More details can be found at http://scied.unl.edu/pages/mamres/pages/demos/denver/collapsing_can.html

Resource: http://www.madsci.org/experiments/archive/871082838.Es.html
 

Materials: Pre-sliced American cheese (the smooth, unnaturally yellow stuff that comes individually wrapped in plastic) works best
 

Procedure:
First, take a slice of cheese and pull on the edges. It should tear apart. Eat it. Get a new slice.

Now, make a small incision in the middle of the cheese slice with your fingernail or a butterknife, parallel to the edge of the cheese slice. Then pull on the two cheese edges parallel to the incision (so that you're pulling in a direction perpendicular to the incision). Watch how the small defect you've introduced into the cheese slice concentrates the tearing. Observe the shape of the propagating fracture, especially the pointed tips where the tearing is taking place, and how the fracture tips move faster as the fracture gets bigger. Eat the torn up slice and get a new one.

Now try repeating this, only this time make two incisions near the middle of the cheese, maybe about an inch apart, and make them offset diagonally from each other (see picture below). Now when you pull on the cheese, fractures will begin to propagate from each of these defects. As the tips of these fractures begin to propagate past each other, they will begin to curve toward each other, and eventually link up into a single fracture.

    +--------------------+
    |                     |
    |        |            |
<- |                     |  ->
    |           |         |
    |                     |
    +--------------------+

Safety Concerns:  Don't eat the cheese if you're lactose intolerant!

Explanation: What you are doing is creating tension fractures, an important experiment for understanding how things pull apart. Like your slice of cheese, the crusts of the Earth and other planets sometimes get pulled on by tectonic forces. This can create tension fractures, some of which will link together to form larger faults. As people who live in earthquake-prone areas know, big faults can be bad news for the people living nearby! Tension fractures are also seen as deep cracks on glaciers, or as the magma-filled dikes which supply molten rock to the "curtain of fire" eruptions in Hawaii. A more everyday example is cracks in the surface of an asphalt road. If you look at these cracks while you're walking down the road, you may find patterns of cracks much like the ones you produced in your cheese experiments.

When you pull on a piece of cheese, you are creating tensional stress throughout the volume of the cheese. If there is a defect in it (like the incision you made), the stress cannot be transmitted across that defect (the walls of the incision can't pull on each other), so the stress that would normally be transmitted across the defect is instead concentrated around the edges of the defect. To visualize this, try drawing a square like your piece of cheese, and then draw evenly spaced lines from one side to the other, parallel to the direction you are pulling. Don't let any of the lines cross the fracture...instead, make them curve around the nearest edge of the fracture. The concentration of lines you get around the edges of the
fracture represents the concentration of tensional stress. This concentration of stress means that the cheese will want to split apart around the edges of the incision. The bigger the fracture gets, the more stress will be concentrated at the tip of the fracture. This is why it gets easier to pull on the cheese as the fracture grows. When the tips of two
fractures go past each other, the direction of tensional stress that the fracture tips "see" changes because the stress cannot be transmitted in a straight line across that gap; it is curved around by both of the fracture tips. To visualize this, try drawing the piece of cheese as it looks as the fractures start to bend. Draw the lines across it as you did before, and see how the stress direction is bent between the fractures. This is what makes the fractures bend toward each other and link up into a larger "fault."

Lift Off - Arianne Glagola

Intended Audience: Middle School
Purpose: To determine why the shape of a bird's wing is important for flight.
Materials: scissors, 1 sheet of notebook paper, ruler

Procedures:
1) Cut a one inch (2 1/2 cm) strip across the sheet of notebook paper.
2) Hold one end of the paper against your chin, just below your bottom lip.
3) Blow across the top of the paper.

Safety Concerns: Try to use kid-safe plastic scissors.

Questions:
1) What do we observe?
2) Where was the air moving fastest in relation to the paper?
3) How did the air movement affect the paper?
4) How would the shape of a bird's wing have to affect the speed of air moving across it?

Results/Observation:
The air was flowing quickly above the paper strip and, as a result, the paper lifted toward the stream of air.

Why/The Science Principle:
1) The faster the air moves, the less pressure it exerts on objects above and below it.
2) Below the paper, however, the air is still pushing equally in all directions.
3) As a result, the upward push on the paper is greater than the downward push by the moving air.
4) We observe, in the outside world, that airplanes and the wings of birds are designed to force the air more quickly across the top of the wing. This design results in an upward push called lift.

Source: Janice VanCleave's Biology for Every Kid.

Objective: Balance a ping-pong ball in mid air using only a hair dryer and sense the forces on the ball to remain in its place.
Materials: Ping-pong ball, hair dryer, tape and dental floss.
Procedure:
1. Attach 12 inch piece of dental floss to ping-pong ball with tape.
2. Point hair dryer straight up and turn it on.
3. Gently place ping-pong ball in the air stream of hair dryer.
4. What happens to the ball?
5. What happens to the dental floss?
6. Slowly tip the hair dryer to the side.
7. What happens to the ball?
8. What happens to the dental floss?
9. Return the hair dryer to its original position.
10. Reach into air stream and gently pull on dental floss attached to the ball. What do you feel?
11. Let go of the dental floss and allow the ball stop bobbing up and down.
12. Slowly tip the hair dryer again, this time keep tipping it until location of ball changes.
13. Where did the ball go?
14. Why do you this is called the Bernoulli Effect?

Scientific Explanation: The force of gravity is pulling downwards on the ball. This exerts pressure on the air moving underneath, making it flow more slowly. The air flowing over the top of the ball is flowing faster that the air underneath. Slow-moving air exerts more pressure than fast-moving air, so there is a pressure difference between the top and the bottom of the ball. If the ball is placed in the right position, the higher pressure underneath the ball pushes up enough to balance the force of gravity. In this position, the forces are in equilibrium.

See also: http://www.exploration.edu

Materials:  1 cup, two mid-sized straws, water

Instructions:  Fill the cup ¾ full of water.  Place one straw in the cup of water, so about an inch of the straw is above the water.  Blow over the opening of the straw in the cup of water with the other straw.  Water will spray out.

MATERIALS: white poster board, blue and red felt tip markers
PREPARATION: Draw a red square inside a blue rectangle as shown

Hello   We need this	Hello   We need this	Hello   We need this llo	PROCEDURE: 1. Stare at the blue and red squares for 30 seconds 2. Now stare at the flat white surface
Hello   We need this	Hello   We need this	Hello   We need this	3. What happened? What can you say about this?
Hello   We need this	Hello   We need this	Hello   Wello

EXPLANATION: When we stare at bright colors for a length of time, the cones in your eyes that see the bright colors get tired. When we look at a white surface, the tired cones rest and the other cones near the same place in the eye take over. We will still see the image we have been staring at but it will be in different colors.

Materials needed:
        -balloon(s)
        -wooden skewer
        -vaseline
Demonstration Procedure:   "I have a balloon.  I want everyone to watch carefully everything I do."
-OBSERVATIONS- [Blow up balloon-only * to * of the way]
"Now what do you think will happen when I take the wooden skewer (dipped in Vaseline) and poke it slowly through the balloon?"
[model what you will do before you actually do it].
-HYPOTHESIS- [Get some hypotheses from the class or have them keep their hypothesis silent in their head.]
"Watch carefully.  I'm not sure what is going to happen."
-EXPERIMENT- [Poke the skewer slowly, through the balloon.  Most of the time it doesn't pop because of the elastic properties of the balloon-polymer]
-RESULTS- "What happened?  Why?  How could we test these ideas?"
Take ideas from the class.  Try the trick again with a variation (examples: A skewer without Vaseline, blowing up the balloon all the way, poking the skewer on the thin part of the balloon, etc.  Let the students decide/brainstorm)
Take home: Students learn about the 4 steps of the Scientific Method and properties of polymers.  They also learn about variation in science experiments.  You can take the demo as far as you want.

Conclusions : The first balloon blows out when the flame touches it. The second balloon doesn't blow out when the flame touches it. The flame heats the rubber of both balloons. The rubber of the balloon without water becomes so hot, that it becomes too weak to resist the pressure of the air inside the balloon. When water inside the balloon is placed in the flame, the water absorbs most of the heat from the flame. Then the balloon does not become very hot; it does not weaken, and does not blow out.

This experiment uses household items to create a chemical reaction that generates carbon dioxide gas that is used to blow up a balloon.

WEAR SAFETY GLASSES

Supplies
½ cup (4oz) vinegar
2 teaspoons baking soda
12 oz empty bottle with narrow mouth
balloon
funnel
spoon

Procedure
Pour vinegar in empty bottle.
Insert funnel in balloon opening.
Spoon the baking soda into the balloon
Tap or shake the baking soda into the body of the balloon.
Remove the funnel.
Stretch the balloon lip over the mouth of the bottle and hold both securely.
Lift and shake the body of the balloon so that the baking soda falls into the vinegar.
The rapid reaction will cause the balloon to inflate.
The amount of inflation will vary depending on the amounts of chemicals used.

What’s going on?
The acetic acid (vinegar) reacts with the sodium bicarbonate (baking soda) to form aqueous sodium and acetate ions, water, and carbon dioxide gas.

CH3COOH (s) + NaHCO3 (s) ? Na+(aq) + CH3COO- + H20 (aq) + CO2 (g)
     acetic acid             sodium bicarbonate        sodium ion         acetate ion           water           carbon dioxide

Cut a long length of string, the longer the better to observe the balloon moving (I used 15 ft).
Tape one end of string to a permanent and stable object, such as a wall, door or tv.  Push the thread through the straw on the other end.  Once thread is in straw, keep it there.  Then tape this straw to an already blown up balloon with two pieces of tape.  When ready, straighten your string so it is tight enough to have no friction.  Let go!!

Basics of Rocket Propulsion
Background: Gases exert pressure on any surface with which they come into contact. In the case of an inflated balloon, gas molecules collide with the interior surface.

If you tie a knot on the end of an inflated balloon creating a closed system, these gas molecule collusions create equal forces on all walls of the balloon, each force has an equal opposing force on the opposite wall, and the balanced equal opposing forces create a pressure of zero within the balloon.

If you inflate a balloon and leave the end open, the pressure at the top of the balloon, opposite the open end, is still pressing against the interior wall of the balloon but the open end does not have a wall for the gas molecules to collide against and there is not an equal opposing pressure and the forces become unbalanced. The balloon will move in the direction of the top of the balloon due to the interior gases pressing towards this direction, as there is no opposing force at the open end of the balloon to counteract this pressure and resulting movement.

Force ¹ zero

Unbalanced Forces = Acceleration = Thrust

Materials Needed: Balloon (longer balloons work better than rounder balloons).Tape (two pieces of approximately ¾ inch, 6 to 8 inches long). One drinking straw. Approximately 25 feet of yarn, string, fishing line, or heavy thread. Optional: one plastic bag.
Insert straw through string and slide to one end. Have 2 students stand at opposite ends of the room holding string taunt. Place two pieces of tape over straw. Inflate balloon. Connect inflated balloon to tape on underside of straw, with top facing furthest distance of string. (Option: tape plastic bag to straw and insert inflated balloon into bag for ease of assembly). Let go of inflated end of balloon to view it travel across the room in the direction of the top of the balloon.
Summary: This demonstration indicates the generation of thrust in a rocket motor or engine creating propulsion. Propulsion: The act of imparting motion to a body that is initially at rest or of changing the motion of a body that is already in motion. Further studies suggested: · Newton's laws of motion. · Gas laws. · The launch height variable of a 2-liter soda bottle rocket due to varying amounts of water and pressure indicating the effect of thrust by jet propulsion.
Jet Propulsion: A means of imparting motion to or changing the motion of a body by using the momentum of ejected matter. As opposed to Rocket Propulsion: a type of jet propulsion in which the ejected matter, called the propellant, is stored within the vehicle.

The set up is: a cup with a cut rubber band attached to the bottom of the inside.  The two ends of the rubber band are tied to large metal nuts. The nuts are pulled over the edge of the cup so that they dangle. When the cup is held with the nuts dangling over the edge from the rubber bands, all forces are balanced.  The weight of the nuts is balanced with the pull of the rubber bands.  The weight of the cup is balanced by my hand holding it up.
Once I release the cup, the cup is experiencing an unbalanced force: gravity.  As gravity pulls the cup down, the nuts want to stay where they were: objects at rest tend to stay at rest.  As the cup drops out from beneath the nuts, they are no longer dangling from its lip.  So the rubber bands are free to pull the nuts into the cup.

SUBJECT AREAS: Chemistry & Physics (a little biology could also be thrown in).
CONCEPTS: Solubility and solutions.

MATERIALS:
1. One can of soda pop.
2. A glass container (cafeteria glass, beaker, or Erlenmeyer flask).
3. Table salt.
4. Teaspoon
5. Basin (to catch the overflow)

PROCEDURE:
1. Pour the soda into the glass. Try to tip the glass and pour along the side so that the pop doesn't fizz too much.
2. Pour about one teaspoon (or more, if you like) of salt into the spoon.
3. Dump the salt into the soda.
4. Watch the fizz rise!

QUESTIONS:
1. How soluble is salt in water?
2. How soluble is gas in water?
3. What happens to the salt when you dump it in the sodapop?
4. What happens to the gas when you dump the salt in the soda pop?
5. Why does the gas dissolve out of the sodapop?
6. How can you apply what you just learned about the solubility of gas in water to aquatic and marine animals? What happens to a fish (or a SCUBA diver) if it moves from a deep area to the surface too quickly?

RATIONALE:
Salt is very soluble in water. Air dissolves in water, but not very well, especially compared to salt. In a solution, the solvent (the water in this case) can only hold so much solute (stuff like salt, sugar, air, etc.) . When the salt is added to the water, the water can't hold as much dissolved air in it, so the air escapes and we see the fizz.

Another way to say this is that the solubility of the gas is decreased. The things that affect the solubility of gas in water include temperature, pressure, and the amount of stuff already dissolved in the solution. A cod fish (or a SCUBA diver) swimming deep in the ocean is under a lot of pressure. If a fisher catches the fish and pulls it up quickly, the pressure that the fish is under decreases. Then not as much air can be dissolved in the blood of the fish. The gas in the blood dissolves out, and the fish has a bloated swim bladder and its tummy will be puffed up. Quick changes like this can kill a fish or a diver.

APPLICATION: SCUBA gear, physiology of marine and aquatic animals, storing sodapop.

http://scied.unl.edu/pages/mamres/pages/demos/denver/coke_joke.html

Mix ahead of time water and blue food coloring until light blue.

Procedure:
1. Poor the colored water into beaker and then the cooking oil on top of the water. The oil and water will not mix because the oil is insoluble in water. The two layers can be stirred but they will eventually separate again.
2. Using the dropper, carefully lower 3-4 drops of red food coloring into the oil. The red food coloring will sit in tiny balls because it is
insoluble with oil.
3. Let the red balls fall down into the water or push them through the oil with a spoon. The red balls will hit the water and mix. This is because food coloring is soluble in water.

Materials: 20ml of vinegar 20ml of vegetable oil then
Mix together and wait about 3-5 minutes
T his is suspension

1)  Pour a little water into the beaker.  Then pour in the cooking oil on top.  (Oil and water are immiscible, so they stay in separate layers.  They can be stirred into a mixture of droplets but soon separate again if left to stand.)

2) Using a dropper carefully lower one or two drops of red food coloring into the oil.  If you are careful the water will sit in tiny balls because it is immiscible with oil.

3) Now, using the end of a spoon, push the balls of food color down through the oil into the water.  Once the balls hit the water, they burst in a cloud of color.  This is because the food color in soluble or miscible in water.

Materials:   1/4 -1 ml  Iodine tincture
  2-5 tsp Cornstarch
2 600ml beakers filled with 200 ml of water
1 zip lock sandwich bag

Purpose:   To explain diffusion across a semi-permeable membrane.

Procedure: 1.  Use a small amount of iodine and cornstarch to demonstrate that iodine is a starch indicator that turns purple in the presence of starch.
2. To one beaker, add the cornstarch and mix well.  Pour the mixture into the zip lock bag.
3. To the other beaker, add the iodine and mix well.
4. Place the bag filled with the cornstarch mixture into the beaker with the iodine mixture.
5. Allow 15-30 minutes
6. Remove the bag filled with cornstarch.
7. Compare the initial observations with the final observations

Results:   It may be helpful to have a "before" and "after" to drive home the changes.  The purple color change occurs inside the bag, suggesting that the bag allowed the iodine particles to move from an area of high concentration, outside the bag, to an area of low concentration, inside the bag.  The cornstarch molecules were also in an area of high concentration, but were not permitted to move outside of the bag due to their larger size.  The amount of time allowed for the demonstration will determine the amount of iodine used.  If less iodine is used, the initial color of the iodine mixture will be a lighter shade, but the student can witness the final color to be closer to that water.  This will allow them a better visual, thus making the connection that the iodine moved into the bag a clearer one.

Materials:
1. Iodine or povo-iodine solution
2. Flour
3. water
4. 2 pieces of plastic wrap
5. 2 clothespins
6. 1 plastic bag
7. 2 ~4 oz plastic, clear cups

Procedure:
1. Mix approximately 2-3 teaspoons of flour with water in the plastic bag.
2. Gently pour a small amount (approx. 1 tablespoon) of the solution onto the center of each piece of plastic wrap.
3. Gently fold the sides up and twist the plastic wrap, creating 2 small bags each resembling the cell.  Hold tight with the clothespins.
4. Add 2-3 eyedroppers full of iodine or povo-iodine solution to each of the plastic cups.
5. Add a few of drops of iodine to one of the bags to create a before and after affect.  Place that bag in the iodine solution.  The flour should have turned from white to dark purple.
6. The second bag is to show the staring point and to demonstrate the procedure.
Simply explain that the plastic is the membrane, and the iodine will cross the membrane as seen in cells when the chloride and sodium ions cross the cellular membranes. This can be easily seen as the flour turns from white to purple indicating that the iodine has penetrated the starch solution.

Procedure: Pour water into container, pour oil into container.  Let it separate.  Add drops of food coloring.  Watch how it falls from the oil to the water.
Why: As you can observe, the drops of food coloring falls from the oil to the water.  However, the water and oil just won't mix. Instead the oil and water form two separate layers.  This is because the oil is less dense and lays on the top.  While the water is more dense and lays on the bottom.  Food coloring is also more dense than oil, so the two won't mix.  When two liquids do not mix together, the scientific word is immiscible.  But the red food coloring and water do mix together, also known as miscibility.

Directions:   Pour the oil and water into separate beakers/cups to show the class. Add some food dye into the water. Get another beaker, and pour some oil into it, then add aome water, and show the class what happens. Then, get your sealable container, and add the water first followed by the oil, observe what happens. Close the container, and shake it vigorously, then set it down and wait to see what will happen. Then, add some dishwashing soap, mentioning that you are adding an emulsifying agent, and shake the container again. Set it down, and observe what happens.

Possible Questions:   Why did the oil keep rising to the top? Which is more dense (oil/water)? What does an emulsifying agent do to the oil?

Explanation:  Water is more dense than oil so it always sinks to the bottom, even if you reverse the order of addition to the container.  An emulsifying agent keeps the oil in very tiny droplets so that it can't flow back together and form a liquid layer on top of the water.

Instructions:
1. Fill a bottle 3/4 full with vegetable oil. A clear bottle will work best.
2. Fill a plastic cup with water and add a few drops of food coloring. Stir.
3. Add the colored water to the bottle with the oil, and screw the lid on tight.
4. Turn the bottle sideways, and watch as the color moves through the oil in funny shapes and blobs.

***Found on www.funology.com***

Pour oil into clear glass bowl; enough oil to easily cover the bottom of the bowl

Pour in a cup or more of water, and observe bubbles of oil coming to the surface.  Also notice any entrained air bubbles that are trapped underneath the oil, and any water bubbles that are floating on the water.  Also observe any plumes, or domes of oil adhering to the bottom of the glass bowl.  Over time, some of these domes may break off and rise as teardrop-shaped blobs.   In addition, the air bubbles trapped at the oil-water interface will begin to group together and form small ‘clouds’.

Select one of the oil domes still adhering to the bottom of the bowl, and place a toothpick or other narrow object down into the dome.  Watch as a portion of the oil dome breaks off and ‘rides’ along the toothpick up to the surface.

You might show how surface tension can keep a small drop of water floating on oil by dropping a small drop of water onto the oil with an eye dropper.

Now, using the food coloring, drop a small drop into the bowl.  Most or all of the food coloring should form small bubbles within the oil.  Now drop a larger portion of the food coloring in, enough for it to drop through the oil and disperse into the water below.  Observe the dispersion and diffusion of the food coloring as it dissolves into the water.

Observe the preference of the food coloring to travel and settle along the bottom of the bowl.  In addition, take note of the effect this food coloring has on the oil domes that are still adhering to the bottom of the bowl.  Apparently, the food coloring helps some of these oil domes to become detached from bottom of the bowl, allowing the oil droplets to rise up to the surface, leaving behind ‘streamers’ of food coloring in their wake.

Also, the dispersion of the food coloring throughout the water is not complete until the water is mechanically mixed.

Have fun!

Fill beakers with the same amount of water
Heat one beaker until water is almost boiling
Cool the other beaker so the water is ice cold
drop food coloring into beakers so that the kids can observe what happens to the dye in each beaker.

Importance - it is important to get to know your students name as well as a little something about them (whether it be what subject
in school they like, where they live, what their favorite song is, who their favorite artist is etc.)  Students tend to show an interest in
you, if you show an interest in them.

Demonstrate example 2.

Examples:
1. name and object
a. how to play:  arrange students into a large circle.  Include yourself (always try to participate in the activities you use).  In this
game, you say your first name and something else that begins with the first letter of your name.  Example: "Loony, Lori."  The
person sitting next to you in the circle will repeat your "intro," and then make up their intro.  Allow everyone to take a turn till the last
person in the circle has had a chance to introduce themselves.
b. Add on: incentive: for the last few people in the circle, offer them a bonus for being able to repeat everyone's name.  At the end,
offer the same bonus to anyone who'd like to try to repeat everyone's name again.  (keep track of time though)

2. ball throw
a. materials needed:  a ball
b. how to play:  arrange students into a large circle.  Next, have everyone introduce themselves (may be by using Name and Object
game).  Give one student the ball.  That person has to say their name, say the name of another student, and then throw the ball to
that person.  You must throw to a different person every single time until all student's names have been said.
c. Extras:  this allows students to 1.  learn the names of the other students, 2. allows for you to remember their names easier, 3. get
them involved in something physical (everyone learns differently and you'll capture the attention of those that like to learn by
DOING things), 4. you've just gotten everyone to participate in an activity, 5. you've just got everyone to say something aloud.
d. Add on:  for a test review, use a large beach ball and attach questions on the ball that the students pass around.  As they catch
it, they are to read out loud the question that their right thumb (or which ever finger you choose) is closest to.  They will then
attempt to answer, and the class may have small discussions following or help the student answer should they not be able to
answer correctly.

3. who am I?
a. Materials needed: paper, pencil, tape
b. How to play:  you are going to tape onto the back of each student, the name of a famous person.  Students are to stand up and walk around asking other students in the room, questions that can be answered by a "yes" or "no."  (i.e. "Am I living?  Do I playsports?") Students answering, may only answer with a "yes" or "no."  When a student feels they know who they are, have them write their name on the board along with the name they think is taped to their back.  They may then go around answering questions till everyone feels they know who they are.
c. Extras:  this allows students to 1.  get out of their chairs, 2. communicate with other students, 3. have a break from lectures and note taking, 4.  get used to asking questions.
d. Add on:  you may include that they introduce themselves to the person they're asking a question to, before they ask the
question.

4. Rhythm and concentration
a. How to play:  arrange students into a circle.  Each person says their name.  Everyone then learns to rhythm:  slap your thighs
twice, clap your hands twice, and snap your fingers, first one hand and then the other.  Once everyone has learned the rhythm, names are added on the finger snaps.  The leader will:  slap, slap, clap, clap, snap and state his or her name at the same time, andthen snap and say someone else's name.  That person becomes the leader and calls the names for the next cycle.
b. Extras:  this allows students to 1.  participate in something physical (slapping and clapping), 2.  develop their coordination, 3. participate vocally. c. Add on:  try using different rhythms or increasing the speed as they get better at the game.

5. Right and Left
a. How to play:  arrange students into a circle.  One player is "it" and stands inside the circle.  A player in the circle is approached and "it" call "right 1-2-3-4-5" or "left 1-2-3-4-5."  The player addressed must give the person's name to the left or right before "it" cancount to five.  If "it" wins, he or she takes a position in the circle, and is replaced by the player who could not give the correct nameby the count of five.  If the person in the circle gives the correct name.  Do not allow students to talk other than to answer to "it."
b. Add on:  periodically, have the class stand from their seats and change to a different seat so they have new people with different names on each side of them.  (gives the "it" person more of a chance.)

This experiment involves two parts. The first one takes a little bit longer than the second. Make sure you emphasize the second because the combination of the two experiments drive the main point of the demonstration.

In the first part, you have three cups filled with 50 ml each of water. In each you put a few drops of liquid soap and mix, creating a soapy solution. With the first cup and using a straw, draw up some of the solution by sucking, being careful not to bring the solution to your lips. This may take some practice. Next, blow out and what happens is bubbles.

In the second cup add, add a half teaspoon of sugar and do the same steps of trying to make bubbles. You’ll find that bubbles do form. In the last cup, add a half teaspon of salt and try to make bubbles. The result is no bubbles form and you get a watery solution.

Now, the next experiment in a separate cup, add a pinch a salt into a similar solution and ask if bubbles will be form. Follow as above and you should be able to from bubbles. This is an example of the hypothesis leading to an experiment and then returning to an alternate hypothesis with a corresponding experiment. You might also mention that it’s with a number of these similar type of experiments and supporting research that theories develop.

Supplies and equipment needed:
1 Erlenmyer flask or other clear beaker with narrow mouth
2-3 thumb-size chunks of dry ice
One latex glove
Optional : 2-3 Eppendorf microcentrifuge tubes
             tweezers
           small screwdriver

Optional: Tightly sealing an Eppendorf tube to which a pea-size chunk of dry ice has been added creates a mini CO2 bomb.  Sublimation will cause the cap to explode off the tube with a sharp pop, creating interest.  Be careful that flying caps or tubes do not jeopardize student safety by tossing the loaded Eppendorf on the floor immediately after loading it.

So how does this work?  The apparatus demonstrates that an object will maintain balance as long as the center of mass is directly under the pivot point.  In this demonstration the pivot point is the edge of the table, and the center of mass is in the head of the hammer.  By manipulating the position of the hammer head to be directly under the edge of the table, the apparatus stays suspended.  A key in this apparatus is that a wooden handle is used.  Otherwise, any more weight would cause the whole apparatus to fall due to the center of mass moving away from the pivot point.

This is a great experiment with children because the demonstration fools the eyes and doesn’t make sense unless physical laws are brought in to explain it.  By showing a "cool" demonstration children learn about pivot points and center of mass.

Pollution: Observe the outreaching effect of a small amount of pollution on a stream and its wildlife.

Materials: 1 gallon (4 L) glass jar
Measuring cup (250 mL)
Red food coloring

Procedure:
1. Pour one-half cup of water into gallon jar.
2. Add and stir 2 drops food coloring to jar.
3. Add 1 cup of water at a time to the jar until the red color disappears.

Results: It takes about 7 cups of clear water to make the red color disappear.

Why: The red is visible at first because the molecules of red color are close enough together to be seen.  As clean water is added, the color molecules continue to spread evenly throughout the water.  They finally get far enough apart to become invisible because of their small size.  This is what happens with some water pollutants.  The material may be visible where it is initially dumped, but as it flows downstream and becomes mixed with more water it is no longer seen with the naked eye.  This does not mean that it is gone.  Just like the red food coloring, it is still in the water and you would be ingesting small quantities if you drank the water.  Similarly, animal life in the stream is affected by pollutants many miles from the source.

Notes
Intro:
• Increase instances of pollution in the news; health risks to humans and wildlife associated with pollutants
• Show newspaper example
• Types of pollution:  Can see (trash) vs. Can’t see (chemicals, sewage spill)
• Soda 6-pack ring, picture of animal stuck in 6-pack ring, closed beach photo
• Lesson focus on those pollutants we can’t see in water

Story:
• Eugene, OR slaughter house on Willamette River – discharged water directly into water
• Stained river red at discharge point
• Easy to recognize water pollution (red color of water) at discharge point, but what about the water quality down river
• Would you swim in the water at the discharge point?
• Would you eat fish caught in waters near the discharge point?
• What about downriver where the water isn’t discolored?

Lesson:
• Water jar = water body (e.g., river)
• Red drops = industrial discharge, spill or dumping into the water body (pollution)

Materials 1 Orange

Procedure:
1. To represent the amount of usable soil on Earth, begin with an orange. The orange represents the Earth, and the orange peel represents the surface of the Earth. Most of us think of this as mostly dirt or soil, but that is not the case!
2. Put one of the oranges aside.
3. Remove three-quarters of the peel from the other orange. This represents the amount of water on Earth.
4. From the remaining peel, remove half of it. This represents areas where there is little or no usable soil (bogs, deserts, cities, mountains).
5. Carefully peel away three-quarters of the remaining orange peel. This represents areas that are too hot, too cold, or too wet for farming.
6. Look at how much peel is left on your orange. This is how much usable soil we have on Earth. It is only one thirty-second of the Earth's surface!

What's Going On?
People take soil for granted because it seems to be everywhere we go. However, as this experiment has shown, that is definitely not the case. We need the soil to survive because it supports the plant and animal life we eat. Soil takes hundreds of thousands of years to form, yet it can be lost and returned to the oceans through erosion in a matter of hours. It is important to appreciate our soil, and to take its conservation very seriously!

What Else To Do: Peel the remaining orange and share the fruit. While you are enjoying it, think about the wonderful soil that the orange trees grew in.

BE CAREFUL! Make sure you wash the oranges before eating them.

Pour about 2 T water in a flask (clear container). Add about 2 tsp of copper sulfate.  Stir the water to make a clear blue solution.

Drop a small piece of steel wool into the flask.  What is the result?

After dropping steel wool into the flas, the copper sulfate solution turns yellowish-green and red specks appear on the steel wool.  This happens because some iron atoms in the steel wool and copper atoms in the solution swap places.  The copper atoms cling to the steel wool, forming tiny specks of copper, a red metal.  The iron atoms take the place of the missing copper to form iron sulfate solution, a yellow substance.

Demonstration: 1. Sprinkle a pinch of baking soda on each sample.
2. From your experience with the foods:
Predict which combination would be the least reactive? - and which would be the most reactive?
3. What do you observe?
4. Is there any relationship between what you observe and which foods you know from experience have a sour taste?
5. Provide an explanation for what you observed.

Demo: Place phenolphthalein solution on the sheet of paper (e.g. fill in the balloon).  Spray windex on the part of the paper that contains
phenolphthalein.  Pink will appear where you have phenolphthalein.  Notice that the pink disappears after awhile.  Ask your students why this is
occurring.  Ask them what would happen if you sprayed the paper again. Spray the paper again and you will see the pink reappear.

Science behind the demo:  The phenolphthalein is a acid-base indicator.  In the presence of an acid or neutral solution, the indicator is colorless.
However, in the presence of a base the solution turns pink.  Windex contains ammonia, a base.  It is the ammonia in the windex that causes a
color change.  Overtime the ammonia will evaporate causing the phenolphthalein to go back to colorless since the indicator is no longer in
the presence of a base.  When you add more windex, you are adding more ammonia.

Procedure:  1)  Fill flask with approximately 75 ml of water
                   2)  Place pH meter inside flask along with piece of tubing
                   3)  Take initial pH reading until numbers slow down to a near halt
                   4)  Record reading
                   5)  Begin blowing into the flask continuously until lungs have expelled all air possible
                   6)  Take second reading

What happened to the pH of the water?
Conclusions:  pH of tap water was approximately 8.40.  After blowing into the flask for 45 seconds to 1 minute, the pH had decreased to about  7.60.  The percent hydrogen in the water is increasing, lowering the pH of the water and making a more acidic solution.

Materials:
A clear glass bottle, 2" X 2" X 8"
A cork top
1/4 cup white wine vinegar
2 tablespoons baking soda
One funnel
Small cup of water

Procedure:
Place glass bottle on a flat surface and do not let observers sit or stand within 5 feet of demonstration.  Remove cork top from bottle.  Place funnel into the glass bottle and then slowly pour the baking soda.  Moisten cork with water. Quickly pour vinegar into bottle and IMMEDIATELY cork it, but not too tightly.  The gas should build up and cause the cork to be popped out of the bottle.

Objective: To observe the chemical activity of mixing baking soda with vinegar.

Materials: Baking soda, cup of water, empty bottle, vinegar, and a balloon.

Procedure: Place 2 teaspoons of baking soda into the empty bottle and add an inch of water. Next, place a tablespoon of vinegar into the balloon and cover the top of the bottle with the mouth of the balloon. When the balloon is on correctly, lift the end of the balloon releasing the vinegar into the bottle where the baking soda and water waits.

Questions: What happens? Does the balloon expand? Does the balloon shrink? Why does it expand? Conclusion: When the vinegar reaches the baking soda, a chemical reaction takes place. During this reaction carbon dioxide is formed. The gas released from its liquid/solid state makes the balloon expand.

MATERIALS:
3 clear plastic cups
3 plain Alka Seltzer tablets
1 ice cube
cool and hot water

PROCEDURE:
1.  Prepare the three cups of water and arrange them from cold(ice cube plus tap water)to cool to hot
2.  Drop one Alka Seltzer tablet in each cup.

CONCLUSION: The hotter water produced more bubbles faster.  The experiment shows that more heat seems to speed up the reaction. One of the products of the reaction of Alka Seltzer with water is carbon dioxide gas.  The rate of production of carbon dioxide bubbles is an  indicator of the rate at which the reaction takes place.

Procedure:
-place candle and bucket next to each other on a sturdy surface
-light candle
-place one part of bi-metal directly into flame and watch as bi-metal bends
itself
-remove from flame and say that bi-metal is actually made of two kinds of
metal, and it bends because one of the metals expands faster than the other
metal upon heating
-place bi-metal in water to straighten it out
-place bi-metal in flame again to view bending
-place bi-metal in water to straighten it out
-extinguish candle

One of water’s important properties is surface tension.  Surface tension is how difficult it is to break the surface of a liquid.  Water has a greater surface tension than most other liquids.  Water molecules are polar, and between these polar molecules, hydrogen bonds form.  When water is in it’s liquid state, the bonds are constantly forming, breaking and reforming.  Collectively, these hydrogen bonds give water a cohesive property.  This cohesion causes the water to behave as though it is coated with an invisible film.  Examples of surface tension are: skipping rocks across a pond and slightly overfilling a glass of water.  Following is an experiment that will demonstrate this property.

1. Bend the end of a 4-inch length of wire into a single loop around a pencil.
2. Bend the loop so that the plane is perpendicular to the remaining length of wire.
3. Fill a glass with water.
4. Holding on to the straight part of the wire, gently press the flat part of the loop against the surface of the water.  What do you see?
5. Once you have broken through the surface, slowly pull the loop up through the surface.  Now what do you see?

Results that you should expect: When pushing the loop down, you should see the surface of the water indent with the loop before it breaks through.  Pulling up, the water around the loop should be pulled slightly above the level of the water in the glass.

Think It Over
Developing Hypotheses—How was each student’s distance from the teacher related to when he or she smelled the air freshener?  Develop a hypothesis about why this pattern occurred.

Teacher Notes:
Skills Focus developing hypotheses
Materials Air freshener spray
Teacher Tips When spraying the air freshener, spray up or down rather than in the direction of the students
Expected Outcome The spray should diffuse evenly throughout the classroom, reaching students at the same distance from the source at about the same time
Think It Over The farther each student was from the teacher, the longer it took for the student to smell the air freshener.  Students may hypothesize that particles in the spray moved from an area of lower concentration.

Procedure
1. Cut out bottom of the plastic bottle
2. Place handkerchief over the are that was cut out of the bottle
3. Fasten the handkerchief to the bottle using a rubber band
4. Light candle
5. Place plastic bottle at 1 foot distance from candle with the handkerchief side of the bottle facing away from the candle
6. Beat on the handkerchief with hand until the candle blows out.

What happened? When you hit the handkerchief, sound vibrations are created. These vibrations cause the air inside the bottle to be stimulated; the stimulated air knocks out the candle at the other end.

Interesting fact: It is completely silent in outer space because there is no air to carry the sound!

Materials and Chemicals:
- 10 mL of ethanol
- 10 mL of water
- two 10mL graduated cylinders
- one 25 mL graduated cylinder

Procedure:  Measure exactly 10 mL of ethanol in the first 10 mL cylinder and 10 mL of water in the second 10 mL cylinder. Pour two liquids into the third cylinder. Allow a couple minutes for the two liquids to mix, then read the volume of the mixture.

Results: The volume of final mixture is not 20 mL (18.7 mL exactly). This is one of examples showing that the volume is not conversed. In the case of mixing alcohol and water the total volume becomes smaller due to the strong interaction (hydrogen bonding) between alcohol molecules and water molecules.

Materials:
Large round balloon
About 20 red raffle tickets
About 4 blue raffle tickets of a different color
Pin
Round yellow stickers, _"
Transparent tape

Preparation: Set aside one of the 20 red raffle tickets.  Push all remaining raffle tickets (red and blue) into balloon.  Blow up balloon, tie off end.  Put a circle of tape on the back side of the set-aside raffle ticket.  Have remaining materials at hand.

Presentation:  Explain to class that many diseases are caused by viruses.  Viruses are much smaller than the cells in our bodies, and they cannot make copies of themselves.  They need to get our body cells to make copies for them.

If the balloon represents a body cell, the virus is much smaller, maybe the size of a raffle ticket (hold up balloon and ticket).  In order to make copies of itself, the virus attaches itself to the outside of the cell (stick ticket onto balloon).  Then the virus directs the cell to make copies of the virus (shake the balloon for dramatic effect, it is "making viruses.")  Eventually there will be so many virus copies inside the cell that the cell will burst (using pin, pop balloon with flourish!) and virus copies will spread all over the place (the tickets should have blown all over).

Our bodies fight this by attaching antibodies to the viruses so the white blood cells can wipe them out.  (Stick yellow round stickers onto the red raffle tickets to represent "antibodies".)  But once in a while, when the virus is reproducing, it doesn’t make an exact copy of itself (hold up one of the blue tickets).  Then the antibody for the original virus doesn’t recognize it, and it goes right past it, it lets the virus go.  The new virus can make us sick again.

Source:  Bill Nye the Science Guy, episode on "The Immune System."

Materials: Celery or carnations Food coloring Water Method: In a container mix food coloring and water. Obtain celery or carnation and expose terminal end in food coloration solution. Demonstration is ideal to start at the beginning of the day so the results are obtained later in the day or preparing the celery the night before so it may be compared in class. Explanation: The celery pulls water up its water conducting cells (xylem) that results in the red coloration at the leaves and the red tint through out the plant.  On a hot sunny day there is more water potential in the leaves than in the water. The leaves will lose water through evaporation that creates negative pressure in the leaves. Now in the soil, there is a higher potential in the soil than the roots, things tend to move from higher to lower concentration so the water will move into the roots, Through the hydrogen bonding between water molecules and the negative pressure in the leaves, the water will be pull up into the plant through its xylem.

Materials: 1 coin, 1 quart jar, adhesive bandage

Procedure:
1. Place the coin and jar on the table.
2. Use your fingers and thumb of one hand and pick up the coin and jar.
3. Hold thumb against the side of hand and secure it in this position with bandage.
4. With your thumb taped, repeat step 2.

Results: Easier to pick up coin and jar with thumb, but difficult without the use of thumb.

Literature Cited  VanCleaves, J. 2001. Teaching the fun of science. John Wiley & Son, Inc. New York, USA. pg: 133-134.

Provide hand out to each student.
Demonstration #1. Using a plastic coke bottle, and a balloon. Fill balloon half full with dxhaled air then connect over bottleneck.
Have students squeeze plastic coke bottles. Then repeat using helium. Have students use calipers to measure the diameter of the balloons for each setup. Record temperature of the room/lab. Record volume of the bottle.

Demonstration #2 using glass bottle, balloon, 2 bath containers, ice water, hot water. Fill balloon half full with exhaled air then connect over bottleneck. Place bottle in cold ice water when in hot water. Then repeat using helium. Have students record the temperatures in the ice and hot baths. Have students use calipers to measure the diameter of the balloons for each setup. Record temperature of the room/lab. Record volume of the bottle (should be the same size).

Handout questions Initial Speculation
What can best explain the differences seen between demo #1 and demo #2? What is the air doing in demo #1? Is the air in demo #2 doing the same? Where is the air coming from to blow up the balloon in demo? Where does the air go when the bottles are cold? Does this action take place in our atmosphere? If so, why not? If yes, then what does this cause? What would you expect to see if you used smaller bottles? Which bottles air is more condensed? Data collection and analysis Students should see conceptual differences between the two demonstrations. Data for demo #2 should provide insight into the properties of air with respect to expansion and contraction. Furthermore, students should see differences in data caused by helium vs. carbon dioxide/exhaled air). It should be expressed by charting the balloon measurements along one axis (say X) and temperature along the other (say Y). Make sure all labeling is properly placed and large enough to see.

Focused speculation vs. refined analysis
Have students combine the data to infer trends. Do they see Charles gas laws occurring? The goal is to get the students to observe gas expansion with hotter applied temperatures and contraction with cooler temperatures. Have the students write a description of what changes they see and what they can't see. Have the students describe too what extent the changes in temperatures affect the changes in balloon size. Does air expand without any changes in temperature? Could this be an experimental control? Explain controls and have them discuss their results by comparing them to this “control” or benchmark. Make the writing assignment one full page consisting of a summary and at least three paragraphs

Final speculation and Summarizing Next have the students share their ideas and summarize those ideas on the board. Let students challenge ideas presented. Never discount those ideas that sound irrational, since in science ideas are never absolute. Decision making The teachers’ role may be to accept or offer other evidence to the contrary to predictions. Gas properties Gas particles move around feely and very fast. As particles in a closed container become hotter gas particles move around faster and push harder on the inside of the container. This can be so great it can even cause cans to explode. This is why it is dangerous to leave spray-paint cans in a hot place. The push by these particles is called Pressure. Pressures are the push and shove between particles of gas within a closed container. Pressure increases linearly with Temperature according to “Charles Law” named after French physicist, Jacques Charles (1746-1823) who made the first solo hot air balloon flight. In a closed volume pressure increases with heat and vise versa. Moreover, if you have a balloon capping a bottle, like in this experiment, air will expand and escape out of the bottle to fill the balloon. Some gases even expand to a greater volume than other gases. This means particles will try to separate even further from one another than that for other gases.
Back to List of Demonstrations

With the tape, label the one cup vinegar and one cup baking soda.
Pour 3 tblsp vinegar and 3 tblsp of water into the vinegar cup.
Pour the vinegar and water solution into the bottle.  Add 5 teaspoon of dish detergent.
Swirl gently to mix. Do Not Shake.
Make a funnel out of a piece of paper and tape it so that it doesn't come apart or you can use a funnel.  Place 3 teaspoons of baking soda into the bottle and swirl.  Observe the reaction and see what you observe?

Procedure:
 Pour a small amount of water into the film case. (Approx. _ of the container)
 Insert one-quarter tablet of Alka Seltzer into the film case
 Cover the film case
 Place the canister top down, and stand back!

Modifications:
You can vary the experiment using different amounts of Alka-Seltzer and temperatures of water. (The hotter the water the faster the reaction- so beware).

Additionally, You can make a rocket launcher by cutting a toilet paper roll with four slits and attaching it to a paper plate with tape.  Place the film canister in the toilet paper roll, and the rocket will shoot straight up!

Procedure:
*Fill the balloon with the water so that the balloon is just larger than the mouth of the bottle.
*Light the tissue (or paper) while you are holding the tissue (or paper) with the tongs.
*Put the tissue (or paper) in the bottle and immediately put the water balloon on top of the opening of the bottle.
*When the fire goes out, the balloon will be sucked into the bottle.
*Remove the balloon from the bottle.
*If you're going to do this procedure numerous times in a row, be sure to allow oxygen to go back into the bottle after each run through.

Explanation:
With the fire inside the bottle, the air in the bottle gets heated up so that the air particles move around more quickly and some of the air even goes out through the opening of the bottle.  However, once the fire goes
out, the air particles cool and become closer together.  Since air left the bottle and no more air can get into the bottle the pressure within it drops.  With the drop in pressure, the balloon is sucked into the bottle, since things move from areas of high pressure to low pressure.

Procedure:  Have each group of students spin each egg like a top and ask them to note any differences between the two.  The raw egg will not spin as fast as the boiled egg and will not stand on end.  Then have the students spin the eggs, stop and quickly release them.  The cooked egg will remain motionless while the raw egg will resume spinning in the direction it was going before stopped.

The Science Behind The Experiment:  The boiled egg is solid, so when it is spun all the mass is rotating at the same rate.  The raw egg is fluid on the inside.  When it is spun the fluid remains almost static, giving the egg far less angular momentum.  When the solid egg is stopped all rotational motion ceases, so the egg remains still when released.  When the raw egg is stopped, the fluid continues to rotate inside the egg, therefore when it is released the egg resumes its rotation.

Procedure:
- Lubricate inner rim and mouth of bottle with oil using paper towel
- Fold paper into a fan so it will fit down bottle
- Light paper with match and drop into bottle
- Immediately place egg onto mouth of bottle
- As vacuum is created, the egg will be sucked into the bottle!

Instructions:
Wash and dry the juice bottle
1.  Peel the egg
2.  Cut or tear the newspaper into strips
3.  Place the strips into the juice bottle
4.  Light the strips on fire.  Adult supervision required.
5.  When the paper starts to burn, place the egg over the opening of the     bottle.
6.  Wait..keep waiting...
7.  The egg will be pressed inside the bottle witha loud pop!

Explanation:
The pressure in the bottle was reduced when the fire used up the oxygen inside.  The force of the air pressure outside of the bottle, pushed the egg inside.
Reference:
Egg in a Bottle by Belinda Mooney, http://www.lessontutor.com/belm14.html

Instructions:
Fill bowl with hot water and fill saucepan with cold water.  Slip the balloon over the mouth of the plastic bottle.  Set the bottle in the hot  water.  The balloon will puff up as the heat causes the air molecules to become faster and expand the air.  Place the bottle in the cold water and  watch the balloon deflate.  The air molecules are cooled and slow down.

Procedure:
Take the straw in hand and try to plunge it into the potato.  Do not cup your hand around the straw (you don't want the straw to have added strength due to your grip!).  The straw should just bend or crumple.
Now plug up the top of the straw with your thumb.  Keep your thumb in place!  Holding the straw firmly, plunge it into the potato again.  It should penetrate (go in) and now have a plug of potato in the straw.

Why?
Air takes up space!  When you put your finger over the top, you stop air from flowing in and out.  The trapped air adds pressure inside the straw, which exerts a force outward (on the inside walls of the straw).  This adds strength to the straw and allows it to penetrate the potato surface. When the plug of potato is inside the straw, the air is even further pressurized and tightly packed inside the straw.  With your thumb still in place, you may try snapping the part of the straw with the packed air with a flick of your finger (a student may assist with this part).

Materials: 1-balloon

Procedure:
1. Obtain a balloon and blow it up with several breaths.
2. Then release it from your fingers.
3. Ask for observations as to what happened to the balloon when it was released from the hands.

Materials: A slinky and a volunteer assistant.

Procedure: Stretch the slinky out between you and a second person.  Take up as much slack as possible without bending the coils.  A primary, or P-wave can be modeled by either rapidly moving your hand towards the other person, or by sharply hitting the back of your hand.  This will create a compressional motion through the slinky representing a wave that would displace material in the same direction that the wave is traveling.  A secondary, or S-wave is modeled by moving your hand in an up and down motion.  This produces a lateral motion through the slinky that represents a wave that would displace material in a direction perpendicular to that which the wave is traveling.

This proves that gravity is a constant force.

You will need:
a. a large glass test tube
b. a smaller glass test tube
c. water
d. a pan or bucket

Instructions:
Glass test tubes work best for this activity.  It des not matter what size  test tubes are used.  However, the smaller test must just fit into the larger  tube.  You may need to try different combinations of sizes to determine which
pair works best.

Make certain the test tubes are clean, especially free of soap or detergent. Fill each test tube full with water.  Holding both over the catch pan, lower and release the small test tube into the larger.  Invert the larger tube.
The smaller test tube does not fall out.  Instead, water drips out of both tubes and the smaller tube rises up into the larger tube, seeming to defy gravity!

To prevent breakage, you may want to place a sponge or some paper towels in the catch pan in case the small tube falls.
Presentation:
When presenting this activity, proceed at a moderate rate.  Allow plenty of time at each step of the activity to elicit questions and model analytical thought.
     Pour the established amount of water into each test tube.  Before lowering the smaller into the larger, elicit predictions from your students.  When they offer predictions, ascertain on what experiences they base their
prediction (lowering themselves into a bathtub.)
     Inform the students that you are going to invert the test tube system. Elicit predictions.
     Before inverting the tubes, allow students to make careful observation of the two tubes.  Some might notice a "bulge: of water around the lip of the larger tube.  Ask students if that bulge of water has any significance.  Might it
give a clue to what is going to happen when the tubes are inverted?  (It does.)
     Slowly, but without hesitation invert the tubes.  The smaller should rise up into the larger tube.  Ask students to explain the discrepant event.  Suggest that they use drawings to indicate all of the forces involved (gravity, adhesion, cohesion, air pressure, etc.)
     Reinforce to your students that experience, very careful observations, and analytical thinking provide a basis for good predictions.

Content:The polar nature of water molecules causes them to be attracted to each other.  That is why water forms beads, drops, and the skin on the surface of a pool of water called surface tension.  This type of intermolecular
attraction is called cohesion.

An attraction between dissimilar types of molecules, such as glass and water, is called adhesion.  Both forces are responsible for the bulge of water hanging out over the edge of the glass lip on the test tube.

The bulge is an indicator that there is an attraction between the water and the glass, and the water and itself.  In this case, the attractive forces are stronger than the pull of gravity.

Turbidity is indicative of sediments, or other particles, suspended in the water (seawater or freshwater).  Visibility, the distance one can see underwater, depends on the degree of turbidity, or how much sediment is suspended.  Areas with high water movement, such as the surf zone or a river mouth, will stir up sediments and diminish visibility.  This demo shows how turbid water has poor visibility compared to water with little or no sediments.  Place the two beakers or jars over words or messages on a piece of paper.  Observers will find that the message is difficult to read through the water with suspended sediments, indicating poor visibility.  With a large group, do this demo on an overhead projector using a transparency with 2 separate messages.

Materials:  12” wooden ruler, at least 12” of string (shoelace), hammer

Objective:  To balance a ruler over the edge of a table by hanging a hammer from the ruler and having only 1mm of the ruler in contact with the table.

Directions:  Start by tying one end of the string to the handle of the hammer, about 3” away from the head.  Then tie a loop, large enough to slide the ruler through, about 4” away from the point where it is tied to the hammer.  You may have to play around with the length of the string depending on the weight and length of the hammer you use.  Then hold one end of the ruler on the table and slide the open loop over the ruler until the loop is almost at the table.  Now, with the head of the hammer facing the table, let the base of the hammer rest on the suspended end of the ruler.  Let go and the ruler should stay suspended.  If the ruler is not level and is angled towards the ceiling, lengthen the string between the ruler and hammer.

Extra:  You can enhance the demonstration by first shortening the string to angle the ruler towards the ceiling and then placing objects on the suspended end to see how much weight the suspended ruler can hold.  Results will vary based on the initial angle of the ruler.

 In order to perform this experiment you will need the following materials:

• One ruler or stick or pencil
• A glass or large beaker (this should be at least half the height of the object to be placed inside)
• Water

What’s going?  When light travels from one medium (air) to another (water), it changes speed thus causing an object to look as though it is bent. This is what we call REFRACTION!!

Burn the candle long enough for the wax to melt around the wick. Blow out the candle (if use snuffer, the smoke will come up in a straight line.) Put the flame directly into the trail of the smoke and the candle should light up again.

Reason: the trail of smoke is vaporized wax.
Source: MadScience

Materials:Short Candle
A Fireplace Lighter
Wide-Mouthed Jar

Procedure:
1.Light the candle and put the jar over it.
2.Count how long it takes for the flame to go out.
3.Then, hold the jar over the lit lighter until the flame goes out, and quickly put the jar (open side down) on the table.
4.Re-light the candle and quickly put the jar over it. The candle will go out immediately because there is very little oxygen in the jar. The light used up the oxygen in the jar.

Safety Concerns: Only perform this experiment with adult supervision. Lighters are dangerous and should be used with caution.

Note: This experiment is from funology.com at http://www.funology.com/laboratory/lab016.cfm

Materials: 1 regular size trash plastic bag, and a hair dryer.

Procedure:  Turn on the hair dryer and wait till the air gets hot. Then fill up the plastic bag with the hot air. As soon as the bag is full of hot air, turn off the hair dryer and release the plastic bag.  The plastic bag should rise.

Explanations: Hot air rises due to having a lower density, causing the plastic bag to rise.

Safety Concerns: Be sure to turn off and unplug hair dryer at the end of the experiment. Keep plastic bag away from hot air dryer. Plastic bag will melt if kept in contact with hot air for too long.

Why does this work?
The melting point of alcohol is higher than that of water so the alcohol burns first.  The water has a lower melting point so the
water bonds do not break as fast.  If you keep the fire going, eventually the water will evaporate and burn the dollar bill.

When can I teach this?
This is good to teach during chemistry.  You could demo it to observe chemical reactions and/ or during bonding.  You could
also do it to demonstrate the scientific method or forming hypothesis.

For additional information, go to http://scifun.chem.wisc.edu/HOMEEXPTS/FIREBALLOON.html

Description:  Into the cup, pour just enough water to cover the it’s bottom.  Light the candle and place it over the stand.  Suspend the cup just over the candle flame. Allow enough time for the small amount of warm or hot water to heat to boiling.

Explanation: The candle heats the air beneath the cup.  Heating is an energy transfer that causes the molecules in the air to accelerate and collide with the molecules in the bottom of the paper cup (since the wax is removed).  The paper DOES NOT BURN because the molecules in the paper transfer their momentum to the water molecules in the cup.  Water has a large specific heat, which enables it to absorb the heat energy transferred by the paper from the flame. The water eventually boils.

Applications: May be used in discussions about the specific heat of water, life saving properties of water, heat energy transfer, transfer of momentum, liquid/gas phase changes (boiling)

Explanation
 Students often struggle to conceptually understand how much 1 gram, 1 Liter, and 1 meter each represent.  When discussing the measurements length, mass and volume, use the following objects.
1 meter is the length of your leg, from the floor to your hip. 1 meter is also the length of the fingertips of one arm to the armpit of the other.
1 liter is half a 2 liter bottle. 1 liter is also the volume of 3 cans of soda. Therefore, it takes 6 cans of soda to fill up a 2 liter bottle.
1 gram is the mass of 3 cornnuts, 1 large paperclip, or even 1 jellybean. Review these examples and have students create their own. This is an excellent way to create a personalized concept of each metric measurment.

Materials:  None, just brave students.

Procedure:
1.  Ask nine to twelve students to stand in a straight line facing forward shoulder to shoulder, all facing the same direction.  The students should not be bracing themselves against each other but their shoulders should be touching.
2.  Stand at one end of the line and give a gentle push toward the other end.  Have the rest of the class make observations.  Repeat as often as desired for students to get the full effect.
3.  Now ask the students to interlock or link their arms.  Pull the first student forward and backward until the entire line is moving.  Still have the class make observations and repeat as necessary.

Explanation:
These demonstrations represent two different types of waves.  The first is a longitudinal or compressional wave (sound, earthquakes) and the second is a transverse wave (light,water, earthquakes).  As the demonstrations show, a wave is simply energy moving through a medium (water, the earth, students), the medium itself does not generally move. You can also use slinkies and ropes to get the same effect.

Materials: Gather up 15-20 old credit cards, phone cards, supermarket cards or frequent flier cards.  Plastic strips of similar size, thickness and density will work also but you will usually find plenty of your old cards at home.  One card for every two students is recommended.

Demonstration: Pass the cards out to the students and simply instruct them to start bending the cards back and forth, first slowly then very rapidly.  Instruct them to continue bending the cards until they begin to break.  Note that what they are doing can be described as "work" as they are expending increasing energy to bend the cards.  The more rapidly they bend the cards back and forth, the more work they are doing and the more energy they are expending.

Observations: They will observe two things as the cards get close to their breaking points: 1) An odor; and 2) Significant heat.

Discussion/Conclusions: This is a simple, hands-on demonstration that might be used to introduce the concept of work as energy and energy transference.  It would be suitable for Middle School as well as High School but post demonstration discussion differ in both scope and detail (concepts versus problem solving).

Procedure: Hold the target high in the air.  Take few steps back away from the target and aim towards it at an angle, positioning the gun at the lower height than the target.  Then, simultaneously release the target and fire the dart gun.

Result and explanation:  The dart should hit the target because both object (the dart and the target) are experiencing the same acceleration only due to gravity, therefore the distance that the target will fall is the same as the dart.  This means if the experiment was done in zero gravity the target will remain at the height where it was released and the dart will hit the target following a straight path.  However, due to gravitational acceleration the two objects will fall at the same distance and collide with each other.  The velocity of the dart determines the distance of collision between the two objects.

 In this experiment, the students will test if weight or the length of the string has any effect on the number of swings during a certain period of time. The group will be formed of three students.
 First, the students will do the swinging using a short string with a one ounce of weight. They will hold the line at a thirty degrees angle and let it swing freely for one minute. They will count the number of swings and record it down. Then they will double the amount of weight and try to predict the result before conducting the experiment. After they perform the experiment, they will notice that doubling the weight causes the swing to take double the time.
 After they are done with the first part of the experiment, they will repeat the same procedure but using a longer string. By the end of this experiment, students will realize that having a longer string means that the swings will take longer time.
In conclusion, by conducting the scientific method, students will prove that weight and length of the string have an effect on the number of swings.

Objective: Demonstration of force measurement Materials: as shown in the picture  16 0.040” thick rubber band chained together 3 0.5 liter bottle water as standard weight 1 tape measure 1 8 feet tall stand for hanging rubber band Activity Description: 1. Hang the rubber band string vertically on the 8 feet stand and measure its free length (from hanging point to loading point) using a tape measure and record it as L0. 2. Hang one water bottle on the loading point of the rubber band string and measure the stretched length as L1. 3. Repeat step 2 with 2 water bottles and record the stretched length as L2.  4. Repeat step 2 with 3 water bottles and record the stretched length as L3. 5. Plot stretched length versus total water bottle weight, Finished plot shows a linear relationship. 6. Remove all the water bottles, ask any volunteer to stretch the rubber band string to the L2 length, the amount of force the volunteer feel is 10 Newton.

Materials:   Clay, object to hid in the clay and probes (toothpicks, bamboo skewers)

Procedure:  Hid the object in the clay before you are in front of the class. Then while holding the clay in front of you, take either the toothpicks or the bamboo skewers and probe the clay. While probing the clay to get information on what is inside, data points can be plotted. As the data points are plotted on paper or the chalk board students can visually see the results of the probing. They can then use this information to help them in their deductive reasoning to find out what is hidden in the clay.

Safety Concerns:    Kids can poke each other with the toothpicks or bamboo skewers.

Objective: To demonstrate that conservation of momentum also occurs in rotating objects, not just in a straight-line motion.
Materials:  Bicycle wheel, chair with ability to rotate, rope (about 1 metre long)
Demonstration: Have a student volunteer hold bicycle wheel at the axis. Have student simply move wheel about and tell class how easy it is. Now spin wheel for student and have them try to move wheel about again. Have the student tell the class what he notices different this time.
Now have student sit on the chair also holding the wheel at the axis. Make sure their feet are off the ground. With wheel not spinning, once again have student move wheel about, pointing out to the class that there is no rotational movement. Now spin wheel and have student move the wheel about. Ask class what they notice is happening to student's position. (should be gently rotating)

Next take wheel from student. Have student outstretch their arms (and legs as well if they can). Spin volunteer and have them bring their arms (and legs) inwards and then outwards. Have class notice the change in angular speed. Bring student to a gentle stop.

Next step, attach rope to one end of the axis of the wheel. Hold other end of rope vertical and with the other hand, support the other end of the axis. Ask class what they expect to happen if you let go of this support. Obviously it will fall and dangle by the rope. Return wheel to vertical position and support axis again. Now have volunteer spin the wheel for you. Ask class again what they expect when you let go of support again and only be holding the rope. The wheel will stay vertical while spinning, but will gently precess around the rope.

Explanation:    Conservation of Angular Momentum is where Kinetic Energy (before) = KE(after)
i.e.   KE = 0.5*I*w*w   where I(Inertia) = mrr
and w is angular velocity (rad/sec)
Therefore,              KE = 0.5*mrr*ww
So, if you decrease r(radius), the arms of the spinning student, w must increase to compensate, therefore student will spin faster. (and vice versa)When you move the spinning wheel, you apply a Torque(T) which in turn produces an angular acceleration(a), i.e.    T = Ia        hence the resistance the student feels.

The spinning wheel balancing on one end of it's axis by a rope is a fun demonstration of Precession, but it's explanation is reserved for college level Physics.

Supplies: Shoebox size clear box.... ideally small fishtank, clear tupperware, etc Water 1/4 cup milk flashlight

Procedure: 1. Fill fishtank with water 2. Shine flashlight through tank and observe the color of light from the other side (usually white) 3. Add 2-3 tablespoons of milk. Stir into water. Let settle. 4. Observe light from flashligh again (usually a yellow/orange color)

Reasoning... -This is similar to the sun shining it's light on our atmosphere -The light coming from the sun is white and contains all colors of light (ROYGBIV) -The light we see when we look at the sun appears yellow/orange because the particles in the atmosphere deflect light at different wavelengths and frequencies -That is why the sun appears yellow and the sky appears blue.

The objective of this demonstration was to illustrated the capacity of the  human lungs.

Materials: Two half gallon milk jugs, a tub of water large enough to fit the  jugs in, food coloring, and aquarium tubing.

Procedure: Fill the tub about half full and place it on a table top. Fill  the jug with water until they are full up to the brim. Add the food coloring. (This is just to make it easier to see.) Place the first bottle upside down in the tub and carefully take off the lid and place the lip of the jug against the bottom of the tub so that the water does not come out. Carefully place one end of the tubing into the jug and with a normal breath blow into the tube. The CO2 entering the jug wll displace the water and you can mark the side of the bottle with a marker to show the water level. Carefully remove the jug and place the cap back on. Repeat the same procedure with the other jug and this time take a deep breath and blow into the tube. There will be a significant difference in the volume of water
displced. Thus illustrating the capacity of the lungs.

 Now, add 0.7cc of whole milk to the water and stir well with the long handled spoon.  Shine the flashlight through the milky water onto the piece of cardboard.  You should immediately notice that the light is a pinkish orange and that the milky water appears to be a light blue.

What Happened?
 The light from the beam of the flashlight is white light - composed of many different colors of light.  If the light were shone through a prism, it would break up into its component colors.  When the white light is shone through the vase of water, no diffraction occurs and it continues to be white light.  However, when the light is shone through the milky water, it breaks up into blue light (on one end of the visual spectrum - the shortest wavelengths) and red light (on the other end of the visual spectrum - the longer wavelengths).

 The particles of fat in the milk are small and fairly uniform in size.  When the light hits the fat particles, they scatter the light rays.  The blue wavelengths of light are more easily absorbed by the fat particles than the red wavelengths.  The blue light is scattered in many directions making the milky water to appear blue-ish in color.  The red light is not absorbed and goes through the milky water to show up on the white cardboard.

 There are particles of dust and water vapor in the air.  During the daytime, the sky appears to be blue because the dust and water vapor scatter the blue light rays just as the fat particles scatter the blue light in the milky water.  This effect is called Raleigh Scattering after the late 19th century English scientist, Lord John Raleigh.  In the evening, the light of the setting sun has to travel through the atmosphere tangentially and through a long distance of air to get to our eyes.  The short, blue wavelengths are absorbed and the longer red wavelengths get through, just as they get through the milky water onto the white cardboard.  The more dust particles or water vapor in the air, the more brilliant the sunset.

        Each of these experiments illustrates the conservation of angular momentum and torque.  In the first case the torque that would normally cause the wheel to rotate downward and fall instead just causes a relative change in the angular momentum that is already there.  Seen another way the top of the wheel must move forward to fall, but by the time it has moved forward it has also moved to the side giving a net result of a turn.  (In some ways this is like orbital motion.)  In the case of turning the wheel over on the rotating chair, turning the wheel over reverses the direction of its angular momentum.  The universe compensates by making you turn in the direction the wheel was turning originally to make the total angular momentum the same as in the beginning.

Explanation:
The bottle was filled with air before covering it with the coin. The moisture on the opening of the bottle functions as a seal between the inside and outside of the bottle. When the bottle is placed in the hot water, the air inside the bottle is heated and this causes the air inside the bottle to expand. The only way it can escape from the bottle is through the opening, and thus it has to lift the coin. The coin falls back, more air expands and lifts up the coin again. When this sequence of events happens quickly, a vibration of the dime is caused.

Without the moisture on the opening of the bottle, the coin does not seal off the air, so that the escaping air from inside the bottle could just seep under the coin out into the open without lifting the coin. The coin would thus not vibrate.

To Do:
Balance a stack of coins on your elbow.  Snap your arm forward and catch the coins in midair!

The Science:
This trick is not as difficult as it appears. The students will expect all the coins to go flying.  However, inertia is the only trick up your sleeve that will allow you to easily catch all the coins in the
stack. Inertia is the resistance to change. All objects have inertia. Things in motion tend to stay in motion. Things at rest tend to stay at rest. As you snap your arm forward, the coins are left unsupported in midair. The inertia of the stack of coins kept them from dropping long enough to catch them all at once with your hand.

The more massive an object is, the more inertia it has. Therefore you might want to try this trick with five coins or less and see how easy it is to catch. Next try the trick with as many coins as you can gather and compare which amount of coins are less difficult to catch. Ask the students to predict, observe and discuss why they saw what they observed.

1. Bend glowsticks to get them glowing.
2. Turn off lights.
3. Put one glowstick in the hot water and another in cold water.
4. Observe what happens.

I have a whole write up for this that goes in to more detail if anyone is interested. This demonstrates how temperature effects rates of reactions.

Precautions:
 Potassium Superoxide is a strong oxidizer and reacts violently with water.
 - Gloves
 - Safety glasses
 - Perform in a ventilated area

Method:
 Sprinkle approximately two grams of Potassium Superoxide onto a Kimwipe. Roll up the Kimwipe and throw it in the beaker.  Sprinkle 3-5 drops water on the Kimwipe.  After 30-60 seconds the Kimwipe will flare with a bright light and catch on fire.

Explanation:
Potassium Superoxide is hygroscopic, meaning it absorbs water from the air. When the powder dissolves in water it forms a highly reactive Superoxide
molecule O2-.  The extra electron on the O2 attacks water, generating a great amount of heat.  This causes the Kimwipe to catch on fire.

PROCEDURE:
1. Place Ex-Lax tablet in the plastic bag. Using hammer, gently crush the tablet until you have a fine powder.
2. Transfer the powder to the beaker and add 15 ml. rubbing alcohol. Stir until fully dissolved.
3. Using a Q-tip, draw flowers on the paper "window".
4. When the paper is dry, spray one side with the multi-purpose cleaner ("Orange Clean"). Spray the other with Windex. Observe the results.

EXPLANATION:
Prior to being determined a cancer-causing agent, Ex-Lax was 95% phenolphthalein, an acid-base indicator. In the presence of an acidic or neutral solution, phenolphthalein remains colorless. When in the presence of a basic solution, though, it turns pink. On the basis of the findings, then, the multi-purpose cleaner is slightly acidic, while the Windex (w/ ammonia) is basic. Or, as I prefer to see it, the Windex is obviously a better window cleaner, therefore allowing the flowers to be seen.

• Table  sugar
• Concentrated Sulfuric acid
• Small beaker (100-150ml)

• Gloves
• Goggles
• Perform in ventilated area.

Procedure:
1. Place the candle on the plate and light it.
2. Measure 50 ml of vinegar and pour into the clear plastic bottle.
3. Fold the piece of paper in half and use as a funnel to measure 2 teaspoons of baking soda into the bottle.
4. Place the bottle above the flame being careful that no liquid drops from the mouth of the bottle.
5. Observe what happens.

Questions:
1. What does the flame need to burn?
2. Where does the flame get oxygen?
3. What do you think will happen when the vinegar and baking soda mix together?
4. What did you observe when the vinegar and baking soda mixed together?
5. What happened when the bottle was placed on its side above the flame?
6. Why do you think the flame went out?

Explanation:
The vinegar and baking soda react to form carbon dioxide gas.  Carbon dioxide gas is heavier than air.  As the carbon dioxide gas exits the bottle it pushes air away from the candle.  Without air, the candle has no source of oxygen and the flame is extinguished.

Materials:
Toy beads that can be inter-linked in a long chain.

Explanation:
The beads can be used as a visual representation for a chain of amino acids.  The beads strung in a long chain can show primary
structure of a protein.  The beads can also be twisted to show alpha helix structures and secondary structure.  Two chains
twisted-up can show quaternary structure and a final protein made up of different polypeptides.

Slime is easy to make.  Both kids and adults love this stuff!!!  I do!
Ingredients in my demo:
1 cup Elmer’s white glue
1 cup Water
1 tsp Boraxo hand soap in 1 cup water
Few drops of your favorite food coloring

Mix the glue and water and pour into a sip lock bag.  Next add food coloring and mix.  Add 2 tsp of Boraxo solution and close the bag.  Mix the ingredients by squeezing the bag well.  Open the bag and pull out the clumpy material.  Knead this in your hand until the desired slime consistency is reached.

There are several recipes for making slime here are some web sites to check out:
 http://familyinternet.about.com/library/kidrecipes/blslime.htm This site is a cornstarch recipe that requires cooking.
http://www.ericjorgensen.com/html/slime.htmThis site offers a recipe using Polyvinyl Alcohol (acid-free art glue)

There are tons of sites out there.

Explanation:  Prepare string cheese by making it appear like a candle.  Place a small sliver of almond in the top of the string cheese.  Tell students to write down observations about what they see.  Bring out the string cheese, set it on the front table and light the almond.  Ask students to share their observations.  Most likely students will have written about a candle.  Take a bite out of the string cheese and discuss the differences between an assumption and a scientific observation.

On the cards place an X on one side of the card and a (.) on the other side of the card.  (see below)

X                                   •

Give the instructions:
1) Cover your left eye
2) Hold the 3*5 card about 1 foot from your nose
3) Focus on the X with your right eye
4) Slowly bring the card to your nose while focusing on the X . What happens???????????????
5) If students have not observed the dot disapearing then clue them in to focus on the X but observe what happens to the dot.

This expiremnet is a demonstration of the blind spot that exists because of the optic nerve insertion in the retina which lines
the back of the eye. Your brain tends to fill in the detail and this blind spot is not usually noticed.

(1)  Put spinach (or whatever) in blender.  Add just enough water so that after 10 seconds of blending, the mush is about the consistency of thin pea soup.  The blender separates the pea cells from each other.

(2)  Strain the "soup" into another container.  Save the soup!

(3)  How much soup do you have?  Add about 1/4 that amount of liquid detergent (any kind) and start stirring.  The detergent lyses the cell membrane and the nuclear membrane.

(4)  Add about 1 spoonful of enzymes (meat tenderizer) (it doesn't specify for how much soup) and stir GENTLY for at least 5 minutes.  The enzymes break off most of the protein from the DNA strands.

(5).  Fill a *small*  (large container didn't work well) glass container half full with your clean and tenderized cell scum.

(6).  Tilt the jar and slowly pour an equal amount of rubbing alcohol down the side of the jar so that it forms a layer on top of the cell scum. Pretty soon you will see white stringy, snotty stuff rising up from the cell scum.  That is the DNA.  Use a stirring rod to collect the DNA.

I didn't realize it until I had already bought my spinach, but they recommend using green split peas instead, but any living thing is supposed to work.  Probably because they are easier to blend.

Materials Needed:
 all 5 mls:
1)  water
2)  soda
3)  egg white
4)  apple juice
5)  gelatin

Biurets solution
test tubes, eyedroppers or pipettes

Method:
1)  Place 5 ml of each material in a separate clean test tube.
2)  Add 10 drops of Biurets solution to each test tube.
3)  Observe color change.

Conclusions:
1)  The presence of protein in a material causes Biurets solution (blue) to change color to pink-purple.
2)  Protein is present in several of the food items tested.

Step 1.  Make a runny yeast mixture by adding 2 teaspoons of dried yeast and 2 Tablespoons of water.
Step 2.  Add 1 teaspoon of sugar to the yeast mixture and stir.
Step 3.  Pour mixture into glass bottle and put balloon over the opening of the bottle.
Step 4.  Put bottle into a bowl that contains warm water.  Let bottle sit for 15 minutes.

What Happens?
 As the yeast starts to "feed" on the sugar, it produces Carbon dioxide gas.  The gas moves up the bottle and blows the balloon up.

Procedure
1. Put the starch into the container.
2. Add 1-2 drops of the food coloring. (optional step)
3. Add water slowly to the starch while stirring. Make sure not to add so much water that you "drown" the starch.
4. Now play with the mystery goo in front of the class. By slanting the container and moving the goo with your hands, show that the substance exhibits characteristics of a solid and a liquid.
5. Throw away the goo when finished.

Explanation
The viscous mystery goo can be used within a lesson that explores scientific analysis. Students can formulate a hypothesis as to the nature of the mystery goo and then draw conclusions based upon their observations made while handling the goo.

Explore the slime/goop’s properties through touch, kneading, stretching, pouring, bouncing.  Record your observations.

Flinn Scientific
Catalog Nos.: G0038, G0039, G0040                                           Publication No.: 377. 10

Curiosity overwhelms those who see an unrecognizable substance, "What is it?", they wonder, "What can it be?". Capture your students' attention with the "goop" that Ghostbuster Bill Murray made famous...Slime!  Whether used to instigate creative writing from elementary students or to discuss polymer chemistry with advanced secondary chemistry students, slime contributes excitement to every level of classroom learning. Bring a smile to your students' faces...Slime them!

Materials Needed:
Guar gum                                                         Water
Sodium borate solution, 4% (4g/100ml)                Small plastic cups
Stirring rods                                                    Graduated cylinders, 10ml
Graduated cylinders, 100ml                                  Food coloring (optional)
Balance, 0.1 accuracy

Safety Precautions:
Although these substances are not considered hazardous, students should wash their hands thoroughly after handling.
As is always good practice, students should be warned not to ingest the material and to use it only in the manner for which it is intended.
Do not allow Slime to remain on clothing, upholstery, or wood surfaces. The Slime will stain the surface. Clean up any spilled Slime as soon as possible.

Make Your Own Guar Gum Slime
Using a l00 ml-A graduated cylinder, measure 100 ml of water into a 5 ounce plastic cup. If desired, add two or three drops of food color to the water.
Weigh out one half gram (0.5g) of guar gum. Add it to the water and stir until dissolved. The mixture will thicken slightly within one to two minutes.
Add 5 ml of saturated borax solution (4% solution) and stir. The mixture should gel in one to two minutes. You will obtain your best results by making measurements as precisely as possible.

The slime may be stored in an air-tight container (like a zip-loc baggie) to keep it from drying out.
Feel free to play around with the amount of guar gum vs. Borax solution, it’s a great way to change the consistency of the slime.

Displaying the correct way to setup a safe 3-point and 2-point anchoring system.  Though climbers hope that their climb will be accident free,
climbers take precautions to safely get them to the top (or bottom) by using techniques and equipment made to withstand "accidents".  Good
climbers will always have back-up systems to prevent failure from the main system.

Equipment Demonstrated:
Slings
Carabiners

Showed what would happen if there was a failure on a correctly constructed 3-way and 2-way anchor system.  The climber may fall a few inches but
would survive the fall.  However, in an incorrectly constructed system, the climber may fall a few feet (more potential to hit things on the way down) or
may die because the climber has been removed from the system entirely because of a faulty setup.

The last chemical phenomenon you will observe today involves waterlock, a very useful polymer in diapers. Diapers contain sodium polyacrylate, a polymer that can absorb up to 800 times its own weight in distilled water (ACS Operation Chemistry Module, 22). When using tap water, the sodium polyacrylate absorbs about 300 times its weight in water. The amount of water absorbed depends on osmosis. Osmosis is the movement of water, across a membrane, from an area of high concentration to an area of low concentration. When the sodium polyacrylate is immersed in water, there is a higher concentration of water outside the polymer. The sodium polyacrylate absorbs water until there is an equal concentration of water inside and outside. Tap water (and urine) contains ions like Na+, Ca2+, and Mg2+, which lessen the water concentration outside the membrane. In tap water, the sodium polyacrylate reaches equilibrium with less water than when it is in distilled water.

Step 1: You and a partner are going to work with sodium polyacrylate to determine what types of solutions it absorbs readily. Obtain a clean 500-mL beaker. Place 0.5g of sodium polyacrylate into the beaker.

Step 2:  Obtain a clean 150-mL beaker and place 100 mL distilled water in it.

Step 3: Now, to test the water absorbance, transfer the 100 mL of distilled water using 10-mL increments to the beaker containing the sodium polyacrylate. Record your observations after every 10 mL.

Step 4: After properly disposing of the samples and cleaning your glassware, repeat steps 1 through 3 for two more experiments.  First use tap water and then the 0.9% NaCl solution provided.  Be sure to note the difference in the amount of solution absorbed for each trial and the behavior of the sodium polyacrylate.

Materials:
2 Large beakers
Several small beakers
Food dye
Water
stuffing inside a disposable diaper

Demonstration Procedure:  Place a small handful of stuffinting into a large beaker.  Fill several small beakers with colored water.
Pour a small beaker of water into the large beaker filled with beads.  Continue to add a small beaker of water until the beads no
longer absorb the water added.

Instructions
1. Remove cap to soda
2. Blow up balloon to loosen it
3.Stretch opening of balloon over mouth of soda
4.Secure balloon to soda with duct tape
5.Holding thumb over the mouth of the bottle, gently shake the bottle
6.Observe the balloon

The purpose of this experiment is to show the release of a gas from a solution.  In this experiment the carbon dioxode is dissolved in the solvent by applying pressure.  Once the bottle is opened the pressure is released and gas can escape.  By shaking the bottle more of the gas is released and the balloon inflates.

Results:
Bubbles form inside of the bottle and the ballon inflates.  When solids or gases are dissolved in liquids, the solid/gas is said to be the solute and the liquid the solvent.   In soda, solutes such as sugar and carbon dioxide are dissolved in the solvent, water.    Carbon dioxide is dissolved in the solvent by applying pressure.  When the bottle is opened this releases the pressure and undissolved gas at the top escapes .  Shaking the bottle causes more gas to leave the liquid, to the surface.  The escaping carbon  dioxide applies enough pressure on the inside of the ballon to inflate it.

I will take one large potato and cut it into two cubes. One cube will be 1 cm3, and the other will be 3 cm3. I will soak both cubes in an iodine solution for 4-6 minutes. The iodine will react with the starch to form a dark blue color on the potato. As the potato cubes absorb the solution, the dark blue coloring will travel from the surface to the center. When the potato cubes are removed from the solution, I will cut both cubes in half. The smaller cube should be completely blue inside, while the larger cube will have a small white center. This demonstration shows how a smaller cell (with a larger surface-area-to-volume ratio) allows nutrients to enter the cell at a greater efficiency than larger cells.

Set-up:
Cut the stem of the flower so it is about four inches long.
With scissors, start from the bottom of the stem and cut upward dividing the lower two inches of the stem in to right and left halves.  (see figure)
Fill each of the small cups with water and a different food coloring.
Then, place the right side of the stem in one cup and the left in the other.
Leave for approximately 24 hours (depending on stem length) then observe the color changes in the petals of the flower.

Explanation:   Place grains of salt on an overhead projector approximately 10 feet away from the screen.  Ask students what shape the grains are.  Most likely students will say round.  Push the overhead projector further away by about 5 feet and focus the projector.  Again ask the students what the shape of the salt grains are.  As you move the projector back the projected image becomes larger, making the shape of the crystals appear more defined.  Move the projector in increments until students say that the shape of the grains is square or cubic.  After all students have seen that the grains of salt are indeed square in shape, place a piece of rock salt on the projector and point out the cubic shape.  Use this demonstration to launch a lesson about the crystal shapes created as a result of ionic bonding of atoms.

Why It Works:  Pure water and some aqueous solutions are not electrical conductors.  However, some aqueous solutions conduct current efficiently.  The ability of electrical conductivity depends directly on the number of ions present in the solution because ions serve as electricity carriers.  Some materials, such as Sodium Chloride, readily produce ions Na+(aq) and Cl-(aq)  in water, and the bulb shines very brightly.  Thus, NaCl(soln)  contains strong electrolytes.  Other substances, such as acetic acid, produce relatively few ions of  H+(aq) and CH3COO-(aq)  when dissolved in water and conduct only a small current, and the bulb glows dimly.   Acetic acid belongs to the weak electrolyte family.  A third class of materials, such as sugar, forms no ions when dissolved in water and are non-electrolytes.  Non-electrolytes permit no current to flow, and the bulb remains unlit.