The frequency of periodic motion is the number of cycles that are completed in one second.

Frequency is measured in Hertz (abbreviated Hz).

1 Hertz = one complete cycle / second

Example: if a pendulum returns a point of maximum displacement 450 times in one second, it

has a frequency of 450 Hz

Amplitude is a measure of the amount of displacement relative to the equilibrium point.

In the example below, the set of waves on the left have a higher amplitude (A) than the waves on the right.

The highest energy part of the wave (the top) is called the crest.

The lowest energy part of the wave (the bottom) is called the trough.

Waves with higher amplitude carry more energy than similar waves with lower amplitude.

High amplitude light waves are brighter than low amplitude light waves.

High amplitude sound waves are louder than low amplitude sound waves.

High amplitude ocean waves are better for riding dude than low amplitude ocean waves.

Wavelength is the distance between two similar parts of adjacent waves (crest to crest or trough to trough). The abbreviation for wavelength is l

In the example below, the set of waves on the left have a longer wavelength (l) than the waves on the right.

Wavelength also affects the energy carried by a wave.

Waves with shorter wavelengths carry more energy than those with longer wavelengths.

Changing the wavelength of light waves changes the color of the light, short wavelength = blue light, long wavelength = red light

Changing the wavelength of sound waves changes the pitch of the sound,

shorter wavelength = higher pitch