The particles moving exist parallel to the direction they are being moved in.
Longitudinal
The peak of the wave.
Crest
The part of the longitudinal wave where the particles are farther apart from each other.
Rarefaction
Waves that need a medium to travel.
Mechanical
The lowest point of the wave.
Trough
When a wave hits an object and bounces off it.
Reflection
Waves that don't need a medium to travel.
Electromagnetic
The time it takes to complete one cycle.
Period
The change in frequency or wavelength of a wave in relation to an observer moving relative to the wave source.
Doppler Effect
Waves that move at a perpendicular angle to the direction they are being moved.
Transverse
The measurement of 1 crest to the next crest.
Wavelength
The part of the longitudinal wave where the particles are closer together.
Compression
The type of interference where waves are subtracted from each other when overlapping.
Destructive
The measure between resting and the maximum displacement of a wave from equilibrium.
Amplitude
The number of crests passed by in a second.
Frequency