Spectrum • The pattern light produces when passed through a prism or spectrograph • Prism – 3 dimensional object that refracts light. • Spectrograph– device that allows us to see the spectrum
Visible LightRemembering the Order • ROY G. BIV • red • orange • yellow • green • blue • indigo • violet
Electromagnetic Waves • Transverse • Electric and Magnetic • Can travel through empty space (able • Wavelengththe length of one wave • Frequency how often something happens • With waves, it's "how many waves per second“ • Brainpop; WAVES
Electromagnetic waves travel VERY FAST – around 300,000 kilometres per second (the speed of light). All electromagnetic waves travel at the same speed. (300,000,000 meters/second) in a vacuum. At this speed they can go around the world 8 times in one second.
Electromagnetic Spectrum • They all have different wavelengths and different frequencies. • Long wavelength-lowest frequency • Short wavelength highest frequency • The higher the frequency the higher the energy. • Brainpop: Electromagnetic Spectrum
Longer WavelengthLess energyLower frequency Shorter WavelengthMoreenergyHigher frequency ROY G BIV Cook SunlightSanitize Communicate Healthcare HeatRemote control Nuclear Power
Stars – Spectral Analysis Purpose: To determine the composition of stars using a spectral analyzer. Background:1. A spectrum photograph can be sorted across a plate to reveal spectral lines. 2. Lines represent the chemical composition of the star so each star has its own fingerprint. Procedure:1. Examine each star (A, B, C, D) for chemical composition 2. If lines match, the element is present. 3. Check the box if the element is present.
On Back of LAB SHEET:tally # of lines for each color Answer this question on the back: Why do astronomers need to know what elements are in stars? Turn in lab sheet