Measuring water waves in a ripple tank
Lesson details
Learning outcome
I can accurately measure the wavelength, frequency and wave speed of water waves in a ripple tank.
Key learning points
- Frequency of a wave can be measured indirectly from its speed and wavelength.
- Wavelength of a wave can be measured by using a freeze frame of a wave moving along the length of a ruler.
- It is more accurate to measure the length of, e.g. ten waves and dividing by ten, than measuring one wavelength.
- Speed of a wave can be measured by recording the wave moving along a ruler with a timer in the frame.
- Accurate distance and time are measured by freezing the film, played back in slow motion, to track one wave crest.
Keywords
Ripple tank - A vibrating beam in a ripple tank creates water waves in a clear bottomed container that makes the waves easier to observe.
Slow motion - A film played back in slow motion shows everything happening slowly, including the speed of a timer shown in the film.
Wave equation - The wave equation is: wave speed = frequency × wavelength, v = f × λ.
Uncertainty - The uncertainty in a measurement can be expressed as the range of values within which the true value must lie.
Significant figures - The number of significant figures of a measurement depends on how accurately the measurement is made.
Common misconception
In the equation for the speed of a wave, v = f x λ, speed is dependent on frequency and/or wavelength.
Emphasise that the speed of a wave depends only on the wave medium and not on frequency or wavelength.
Teacher tip
The investigation could alternatively be carried out as a demonstration, perhaps using a visualiser.
Content guidance
Risk assessment required - equipment
Supervision
Adult supervision required
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.In which of the following directions does the water move in a water wave?
Q2.Which of the following accurately describes a water wave?
Q3.In which of the following directions should a wooden beam move in a trough of water to create water waves?
Q4.Which of the following type of results do repeat measurements help to identify?
Q5.A result is if it is very different from other measurements of the same variable.
Q6.Which of the following measurements are needed to find the frequency of a water wave?
Assessment exit quiz
6 Questions
Q1.Which of the following pieces of equipment can be used to observe the behaviour of water waves in the classroom?
Q2.The frequency of a water wave equals the number of waves second.
Q3.Which of the following happens if the motor controlling the wooden beam on a ripple tank is made to spin faster?
Q4.The wave speed of a water wave equals the multiplied by the wavelength.
Q5.The frequency of a water wave equals the wave speed divided by the ...
Q6.Starting with the most accurate, sort these methods of measuring the wavelength of a water wave into order of decreasing accuracy.
To help you plan your 10 combined science lesson on: Measuring water waves in a ripple tank, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 10 combined science lesson on: Measuring water waves in a ripple tank, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 4 combined science lessons from the Measuring waves unit, dive into the full secondary combined science curriculum, or learn more about lesson planning.