Wednesday 10-2-13

1. Wednesday 10-2-13 • WU: Compare a radio wave to a microwave. a) Which has a higher frequency? b) Which has a longer wavelength? • Check Starlight Starbright worksheet • Spectrum Analysis

2. Color in the above spectrum on your sheet • What color has the largest wavelength? • Smallest wavelength? • What color has the highest frequency? • Lowest frequency? • What color would you expect to see if its wavelength were: • 600 nanometers? • 450 nanometers? • 650 nanometers? Red Violet Violet Red Orange Blue Red

3. Skip to part 3 (we’ll come back to part 2)

4. Below are the bright line spectra of four elements and the spectrum of an unknown gas. • Which elements are in the unknown? Explain. b) Why are you able to exclude the presence of the other elements? c) Young stars are mostly hydrogen with a small abundance of helium and other elements. Is the unknown a likely spectrum for a young star? Explain your answer. 700 400 Hydrogen and Helium. The unknown has all of the hydrogen and helium lines. The unknown does not contain all of the lines for lithium or sodium Yes this is likely to be a young star because it contains hydrogen and helium

5. -Spectrums A, B, and C are from identical stars. -A represents a spectrum from an unmoving star.-B and C show stars in motion with respect to us • What is the approximate range in nanometers that the black lines fall in for each spectrum. • Which spectrum is that of a star moving toward Earth? Explain. • Moving away from Earth? • In comparison to A, which is moving faster. B or C? Justify your answer. A = 550-570 B= 600-650 C= 430-470 C – Blue shifted (smaller wavelength) B – Red shifted (longer wavelength) C, it is shifted farther from original