Wave Formula

What determines the speed of a wave?A. The source

B. The medium

C. The energy/amplitude

D. The frequency

v = f

Wave Speed

Doppler Effect

• The apparent change in frequency due to the motion of the source (or receiver)

• The Doppler effect is applied to ALL waves– Sound– Water– Light– etc

No Motion - No frequency change

Motion = apparent frequency change

Smaller frequency

Lower pitch

Larger frequency

Higher pitch

Point Source – MovingDraw this picture

How has changed in the direction of motion? is smaller

v = fv does not change

f is larger

Point Source – Moving

How has changed opposite the direction of motion? is bigger

v = fv does not change

f is smaller

• Complete worksheet

What happens when source moves faster that the wave?

Condensation cloud as an F/A-18 Hornet flys at or near the speed of sound.Photo by John Gay.

F/A-18 breaking the sound barrier

B-2 Spirit Stealth Bomber. Photo by Bobbi Garcia.Posted here with permission of the AFFTC.

F/A 9-Lives ……. super sonic kitty