Measuring Waves

This lesson covers the core practical and experimental methods for measuring wave properties — including using a ripple tank, measuring the speed of sound, and measuring wave speed on a string — as required by the Edexcel GCSE Physics specification (1PH0), Topic 4: Waves. You need to be able to describe these methods, calculate wave speed from measurements, and evaluate sources of error.

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Core Practical: Investigating Waves Using a Ripple Tank

A ripple tank is a shallow tray of water with a lamp above it and a white screen below. A vibrating dipper creates waves on the water surface, and the lamp projects the wave pattern onto the screen so it can be observed and measured.

Equipment

• Ripple tank (shallow tray of water)
• Motor with an attached dipper (to generate waves)
• Power supply with variable frequency control
• Lamp positioned above the tank
• White screen or paper below the tank
• Ruler (for measuring wavelength)
• Stopwatch (for measuring frequency)
• Stroboscope (optional — to "freeze" the wave pattern)

Method