Absorption Spectra Note that the absorption spectrum is

Absorption Spectra

Note that the absorption spectrum is like a negative of the emission spectrum for each element Emission Spectra Absorption Spectra

Fraunhofer Lines (Solar Spectrum) The chemical composition of the Sun can be determined By analysing the Sun’s Absorption Spectrum. The lines were discovered by Joseph Fraunhofer in 1814

Doppler Effect for Light Since light is a wave like sound, the frequency will shift if the source and observer move relative to each other. If the source is moving away, the light is shifted towards the low frequency end of the spectrum i. e. Red-Shifted If the source is moving towards, the light is shifted towards the high frequency i. e. Blue-Shifted

Big Bang Theory In 1924, Edwin Hubble discovers a galaxy outside Milky Way Also noted that light from distant galaxy was Red-Shifted which means that galaxy is moving away. Further discoveries, showed that more distant galaxies are even more Red-Shifted i. e. they are moving faster. http: //video. google. com/videosearch? q=Doppler% 20 effect&rls=com. microsoft: en-us&oe=UTF 8&start. Index=&start. Page=1&um=1&ie=UTF 8&sa=N&hl=en&tab=wv#

The further away the galaxy is the further back in time we are looking The Big Bang is the results of these observations. In 1927 George Le. Maitre proposed that the Universe expanded from a single point. Current estimates have the Universe at 13. 7 Billion years

Polarization To force to vibrate in one plane All E-M waves are transverse waves, including Light For any given light source the plane of vibration is in virtually every plane. Special materials have molecules that have a definite alignment like a picket fence When light passes through a polarizer it only allow the vibrations to pass through that are aligned with the molecules.