1. The Doppler Effect

2. Doppler Effect & Sound Christian Doppler Observing the Doppler Effect Christian Doppler Observing the Doppler Effect Christian Doppler Observing the Doppler Effect Christian Doppler Observing the Doppler Effect Discuss what you hear with your partner Discuss what you hear with your partner

4. The Doppler Effect Applies to anything that produces waves Applies to anything that produces waves –Sound –Light

5. Stationary Source the sound waves are spread out evenly the sound waves are spread out evenly everyone everyoneexperiences the same waves

6. Source in Motion Waves will be Waves will be –compressed in front of the source (shorter wavelengths) –spread out behind the source (longer wavelengths)

8. Breaking the Sound Barrier Mach 1 Object moves just barely faster than the speed of sound Object moves just barely faster than the speed of sound Supersonic Source is moving faster than the sound waves it creates Source is moving faster than the sound waves it creates The sound source will pass by a stationary observer before the observer actually hears the sound it creates The sound source will pass by a stationary observer before the observer actually hears the sound it creates

10. Doppler Effect & Light Waves What happens to light waves when a star moves? What happens to light waves when a star moves? What happens to light waves when a star moves? What happens to light waves when a star moves?

11. Doppler Effect & Light Waves In front of source (star) In front of source (star) –Light waves are compressed –Wavelengths are made shorter as the spectral lines are shifted toward blue end of the spectrum –Called Blue shift

12. Blue Shift

13. Doppler Effect & Light Waves Behind the source (star) Behind the source (star) –Light waves are spread out –Wavelengths are made longer as the spectral lines are shifted toward red end of the spectrum –Called Red shift

14. Red Shift Moving away from you