speed gun

Principle of Speed Gun

Doppler effect Electromagnetic waves (or sound waves) come into contact with another object while traveling; part of the wave is absorbed or reflected. A moving ball likewise absorbs or reflects some of the incoming waves. If … more

Doppler Effect

Doppler Effect

Doppler Effect We have heard an ambulance siren and felt that the ambulance is getting closer. When the ambulance approaches, the sirens sound higher, and when they move away, the sirens sound lower. That is, when … more

Doppler Effect and RedShift

Doppler Effect and RedShift

Doppler Effect By listening to the ambulance’s siren, we can tell if the ambulance is coming or going. When an ambulance approaches with a siren, the sound wave’s wavelength becomes shorter (higher note), and when it … more