Emission Spectrum-Bunsen
Studied spectra of vaporized substances to discover a unique bright line spectrum for each. Bright line or emission spectra used to identify substances.
E.g., study spectrum of star, gas cloud, etc. to determine composition.
Kirchhoff's Laws
1) Solid, liquid, gas at high pressure - continuous spectrum
2) Glowing gas at low pressure - emission spectrum (bright line)
3) Low pressure gas absorbs certain wavelengths of light passing through it, then reradiates at same wavelengths in all directions - absorption spectrum
For a detailed discussion of the Doppler Effect, see the Earth's Revolution exercise under "Laboratory Exercises." A password is required.