1. Ch. 12
Waves
pgs

2. Properties of Waves A wave is the motion of a disturbance
A mechanical wave needs a medium through which the wave can travel
Medium = solid, liquid, or gas
Waves travel fastest through solids, then liquids, slowest through gases

3. Two types of mechanical waves
1. Transverse waves (also called sine waves) – vibrations of the wave are perpendicular to the wave motion
2. Longitudinal waves (also called density or pressure waves) – vibrations of the wave are parallel to the wave motion.

4. Parts of a Wave Crest – highest part of a wave
Trough – lowest part of a wave
Wavelength – the distance from crest to crest or trough to trough
Amplitude – maximum displacement from equilibrium

5. Parts of a Transverse Wave

6. Parts of a Longitudinal Wave
Compressions – regions in which the spring is compressed
Rarefactions – regions in which the spring is stretched
Wavelengths are measured from compression to compression or rarefaction to rarefaction

7. Wavespeed equals frequency times wavelength
Wavelength (λ) has units of meters.

8. A piano string vibrates with a frequency of 264 Hz
A piano string vibrates with a frequency of 264 Hz. Assuming the speed of sound in air is 343 m/s, what is the wavelength?