Post on 19-Jun-2015
The Doppler Effect
May 20, 2013
Objectives
1. Identify the Doppler effect
2. Explain its cause and uses
3. Understand the terms and cause of Sonic Boom
Doppler Effect
Fire Engine Car Horn
Change in frequency due to the motion of the vibrating object
The Doppler Effect
Sound Waves
1. As an object moves toward you, frequency seems shorter – higher pitch
2. As an object moves away, frequency seems longer – lower pitch
3. Never the speed that changes, just the frequency
The Doppler Effect
Uses of the Doppler Effect
Doppler Radar Police Radar
Wave Barrier and Bow Waves When the source is moving as fast as
the waves it produces it reaches a wave barrier
Once it passes its wave speed is creates a V shaped pattern – Bow Wave
Shock Waves and Sonic Booms
Shock Waves – Form overlapping cones that Form a V
Sonic Boom – sharp crack heard when supersonic aircraft’s shock waves pass
The Sonic Boom
Doppler Demo's
Light Waves
1. Red shift – frequency is lower therefore red light is seen
2. Blue shift – frequency is higher therefore blue light is seen
The Stars
Scientists use this knowledge to measure the speed of rotation of the stars
And the distance of galaxies