The Doppler Effect

Frequency and Pitch

• Pitch is the characteristic of a sound that depends on the frequency the ear receives. Pitch is associated principally with the fundamental frequency of the sound wave.

The Doppler Effect

• Named for Christian Johann Doppler who lived from 1803 to 1853

• In general, a Doppler Effect is experienced whenever there is relative motion between the source and the observer.

• When the source and observer are moving toward each other, the frequency heard by the observer is higher than the frequency of the source.

• When the source and observer are moving away from each other, the frequency heard by the observer is lower than the frequency of the source.

Nice Websites

• http://www.kettering.edu/~drussell/Demos/doppler/doppler.html

• http://library.thinkquest.org/19537/

http://physics.gac.edu/~chuck/PRENHALL/Chapter%2014/AABXTCP0.html?I1.x=29&I1.y=28

Define the following

• Define the following with appropriate diagrams:

• Sonic boom

• Shock waves

Red Shift

• A red shift is a shift in the frequency of a photon toward lower energy, or longer wavelength.

• The Doppler Red shift results from the relative motion of the light emitting object and the observer. If the source of light is moving away from you then the wavelength of the light is stretched out, i.e., the light is shifted towards the red.