1. The Doppler Effect

2. Shown by all types of waves

3. Properties of Waves Waves are characterized by two numbers: Wavelength,  (size of the wave) Frequency, ν (number of waves/second) For sound waves, frequency more commonly called pitch For light waves, these are all related by: c =  ν Where c is the speed of light Longer means Smaller ν

4. Electromagnetic Wave Magnetic Field Electric Field

5. The Doppler Effect Shift in the observed wavelength when the source is moving relative to the observer. Examples: Sound Waves (Siren or Train Horn) Light Waves Amount of the shift and its sign depends on relative speed of the source & observer direction (towards or away)

6. Stationary Source Same Pitch

7. Doppler Effect in Sound High Pitch (short waves) Low Pitch (long waves)

8. The Doppler Effect in Light Works same as it does for sound Light moving away from the observer Wavelength gets longer: REDSHIFT Light moving towards the observer Wavelength gets shorter: BLUESHIFT

9. Way to Measure Speeds Observe the wavelength ( obs ) of a source with a known emitted wavelength ( em ) The difference is directly proportional to the speed of the source, v: obs em v c - = em

10. Use on Earth