Waves and Sound

Def: Sound is a form of energy.

In order to produce a sound something must vibrate.

Def: A wave is a means of transferring energy from one place to another.

Def: The amplitude is the greatest displacement from rest.

Def: The wavelength is the distance from one crest to the next (in metres)

Def: The frequency is the number of vibrations per second (hertz)

One hertz = one vibration per second

Def: Velocity = frequency x wavelength

Alexander Graham Bell invented the telephone.

The loudness of a sound depends on the amplitude of the sound wave.

The pitch of a sound depends on the frequency of the sound wave.

Def: An echo means that a sound is reflected off a surface and is heard a short time after the original sound.

Because in a liquid particles are closer together than in a gas so vibrations are transmitted more quickly.

Speed of sound in air = about 340m/s-1

Distance = speed x time

An Echo sounder sends bursts of sound waves called sonar.

	Alexander Graham Bell invented the telephone.
	The loudness of a sound depends on the amplitude of the sound wave.
	The pitch of a sound depends on the frequency of the sound wave.

	Because in a liquid particles are closer together than in a gas so vibrations are transmitted more quickly.
	Speed of sound in air = about 340m/s-1
	Distance = speed x time
	An Echo sounder sends bursts of sound waves called sonar.