# Suggested practical

## Measure the frequency, wavelength and speed of waves in a solid

Jonny Nelson explains waves in a solid with a GCSE Physics practical experiment

There are many different ways that the speed of waves in a solid can be measured. One method involves the use of a vibration generator.

### Aim of the experiment

To measure the frequency, wavelength and speed of waves in a string.

### Method

1. Attach a string or cord to a vibration generator and use a 200 gram (g) hanging mass and pulley to pull the string taut as shown in the diagram. Place a wooden bridge under the string near the pulley.
2. Switch on the vibration generator and adjust the wooden bridge until stationary waves can be clearly observed.
3. Measure the length of as many half wavelengths (loops) as possible, divide by the number of half wavelengths (loops). This is half the wavelength, doubling this gives the wavelength.
4. The frequency is the frequency of the power supply.
5. Calculate the speed of the waves using wave speed = frequency × wavelength

### Example results table

Number of half wavelengthsLength of x half wavelengths (cm)Wavelength (cm)Frequency (Hz)Wave speed (cm/s)
...............

### Risks/hazards

HazardConsequenceControl measures
Cord snappingDamage to eyesEye protection / safety screen
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