Reflection • The bouncing back of a wave when it meets a surface or boundary.
Diffraction • The bending of a wave as it passes an edge or an opening. • This is why you can hear sound around a corner.
Refraction • The bending of waves as they pass from one medium to another. • “Broken pencil” trick
Interference • Waves that exist in the same place at the same time experience interference.
Interference • Constructive: Two crests or two troughs will add together to make a larger crest or trough. They do not average out. • Destructive: Crest meets trough; amplitude is smaller or completely cancels out.
Interference • Of light: creates rainbows in oil or soap bubbles. • Of sound: creates beats in music.
The Doppler Effect • The apparent change in frequency of a moving object to the observer. • Ex: NASCAR, ambulance