May 1 Elements in the Universe

Read the following text and work through the sections and questions. Movement of objects in the universeWe perceive waves at different frequencies depending on our movements. The change in perceived frequency of a wave is called the Doppler Effect.The Doppler Effect is what happens when an ambulance is driving toward you. The siren sounds higher pitched coming toward you and then lower as it is driving away. The change in sound is caused by a change in frequency of the sound waves hitting your ears.Sound is not the only thing that travels in waves. Light does also. Scientists us the Doppler Effect of light waves to determine whether the stars and galaxies are moving toward or away from us. Instead of listening they look. If the star is moving toward us, then it gives off slightly blue light. And if it’s moving away – as most objects in the universe are- it appears redder.Edwin Hubble discovered an electromagnetic property called "Red Shift" which helped determine that galaxies moving away from us had lower frequency wavelengths than galaxies moving toward us.Light from galaxies outside our local group appears to be toward the red end of the spectrum (the Red Shift). Which means that it supports the theory that the entire universe is expanding! Siren Sound Red Shift The Doppler Effect 1. What do you notice about the waves in front of the truck?2. What about the waves behind the truck?3. Think of a car driving by as you walk down a street or a NASCAR race. When do you hear the highest pitch sound? Before or after the car passes you? Record observations about the Doppler Effect picture in the space below. Electromagnetic SpectrumFacts:- Light is emitted from galaxies and stars at different wavelengths.- Each color of light has a different wavelength.- Light behaves like sound. Fill in the blanks with the correct word. If a galaxy is moving away from us the light waves stretch out and makes it appear red in color. If a galaxy is moving towards us, the galaxy appears blue in color. Red Shift on EM SpectrumThe patterns of the black lines tell us what elements are found in a star. Each element has a unique set of absorption lines. Red Shift Conclusion Main Idea: The shift in absorption lines is the basis of Hubble's conclusion that the galaxies are moving apart from each other. As a galaxy moves farther from Earth, the wavelengths of light increase in size and appear more red than it really is. 1.Explain Red Shift and Blue Shift in your own words.2.What does CMB stand for?3.Why do we think the universe is expanding? Number your answers to match each question being answered.