# 4.6.1.2

4.6.1.2 Properties of waves

# 4.6.1.2 Properties of waves

## Content

Students should be able to describe wave motion in terms of their amplitude, wavelength, frequency and period.

The amplitude of a wave is the maximum displacement of a point on a wave away from its undisturbed position.

The wavelength of a wave is the distance from a point on one wave to the equivalent point on the adjacent wave.

The frequency of a wave is the number of waves passing a point each second.

period = 1frequency

T = 1f

period, T, in seconds, s

frequency, f, in hertz, Hz

The wave speed is the speed at which the energy is transferred (or

the wave moves) through the medium.

All waves obey the wave equation:wave speed = frequency × wavelength

v=

wave speed, v, in metres per second, m/s frequency, f, in hertz, Hz

wavelength, λ, in metres, m

Students should be able to:

• identify amplitude and wavelength from given diagrams
• describe a method to measure the speed of sound waves in air
• describe a method to measure the speed of ripples on a water surface.
• (Physics only) Students should be able to show how changes in velocity, frequency and wavelength, in transmission of sound waves from one medium to another, are inter-related.

MS 1c Use ratios, fractions and percentages

MS 3b Change the subject of an equation

MS 3c Substitute numerical values into algebraic equations using appropriate units for physical quantities

AT1 Use of appropriate apparatus to make and record a range of measurements accurately, including length, area, mass, time, volume and temperature. Use of such measurements to determine densities of solid and liquid objects (links to A-level AT a and b).

AT4 Making observations of waves in fluids and solids to identify the suitability of apparatus to measure speed/frequency/wavelength. Making observations of the effects of the interaction of electromagnetic waves with matter (links to A-level AT i and j).

Resources

Video

Practicals

Demo:

### Safety

Asthma attack risk for selected student?