Doppler Effect

The change in frequency due to motion The source or the receiver can be moving

Since both objects are at rest (v=0 m/s), there is no change in frequency.

Since both objects are at rest (v=0 m/s), there is no change in frequency. For Sound, Pitch is same at any point.

Object is moving towards the right, so the frequency changes. Frequency Decreases, Wavelength longer Speed of the wave stays constant Frequency Increases, Wavelength Shorter

Lower Pitch Higher Pitch Object is moving towards the right, so the frequency changes. Frequency Decreases, Wavelength longer Speed of the wave stays constant Frequency Increases, Wavelength Shorter Higher Pitch

Remember, it can be either the sound source (previous ex) or the listener moving

1 Fish, 2 Fish, Red Fish, Blue Fish Blue shift Increase in Frequency Red shift Decrease in Frequency

Blue Shift Red Shift

I see the Light Red/Blue shift comes from Astronomy This shows light frequency (color) which is Red Shifted

Which way is the object sound source moving? Where is the higher frequency? Where is the lower frequency?

The Many Uses of Doppler Radar (RAdio Detection And Ranging) -speeding, air traffic control, weather SONAR (SOund NAvigation and Ranging) Medical -Echocardiogram – velocity of blood flow -Doppler Ultrasound – detects fetal heart tones