What is a wave?

28 January 2015

How many types of wave have you

heard of in everyday use?

Do they have anything in common?

Aims

• Describe the origin of a wave

• Explain the properties of a wave

Key terms

• Displacement: how far the wave is disturbed from its rest position

• Oscillation: a complete to and fro movement; this could be going up and down or sideways

What is a wave?

A wave is a disturbance

moving through a material

What causes a wave?

• The source of a wave is always something that vibrates

• The material that the wave travels through is called the medium

Amplitude, A

• The maximum distance that each point in the medium moves from its normal position as the wave passes

• Measured in metres, m

Frequency, f

• This is the number of waves that pass any point in the medium every second, so it is the same as the number of vibrations per second

• Frequency is measured in per seconds or hertz, 1/s, s-1 or Hz

Wave speed, v

• This is the speed at which each wave crest moves through the medium.

• Measured in metres per second, m/s or ms-1

Wavelength, λ

• This is the length of a complete wave measured from any point to the next identical point – the distance is always the same no matter which point you choose

• It is measured in metres, m

Wavelength, λ

• This is the length of a complete wave measured from any point to the next identical point – the distance is always the same no matter which point you choose

• It is measured in metres, m

fv Where:v = speed of wave / m/sf = frequency of wave / Hz (1/s)λ = wavelength of wave / m

How can we prove this?

1

1

330

330

msf

msv

fv

What would happen if we increased the wavelength of a wave?What would happen if we decreased the wavelength of a wave?

Assessment activity 2.6

• Discuss how you could model the movement of a wave (P3)

• Construct your model or role play it to another group

• REMEMBER: the longer the wavelength, the smaller the frequency. When calculating speed, make sure you change the prefixes