A class uses a shallow ripple tank or a calibrated wave simulation to investigate a wave model. Available equipment and procedure options: Use a side-view scale or calibrated video contrast to compare amplitudes at the same marked point. Design an investigation of how the width of a solid barrier affects the wave amplitude in the centre of the shadow at a fixed distance. Include a reasoned hypothesis, an appropriate range, controls, repeat measurements, a results table or graph, and one specific limitation and safety measure. Do not invent experimental results.

Question

Accepted Answer

Vary the width of a solid barrier; measure the wave amplitude in the centre of the shadow at a fixed distance. Predict A narrow barrier relative to wavelength may give a less pronounced central shadow. Keep wavelength, depth, barrier position and incoming amplitude constant, repeat each setting, and use the evidence to test the prediction. State a testable research question linking the width of a solid barrier to the wave amplitude in the centre of the shadow at a fixed distance, rather than asking vaguely which arrangement is best. A suitable prediction is: A narrow barrier relative to wavelength may give a less pronounced central shadow. Justify that prediction scientifically: Waves bend around barrier edges and can overlap in the region behind it. This is a hypothesis to test, not a result that the experiment must produce. Use 1, 2, 3, 4 and 5 cm as the planned independent-variable settings. Measure the response using the supplied equipment: Use a side-view scale or calibrated video contrast to compare amplitudes at the same marked point. Record quantities with units before calculating any derived result. Keep wavelength, depth, barrier position and incoming amplitude constant. This isolates the proposed cause; changing these conditions at the same time would allow competing explanations for any difference. Take at least three independent trials at each setting, resetting the apparatus each time. Tabulate the setting, individual responses and mean; plot the mean response against the changed quantity and show the range of repeated values. Evaluate this specific limitation: Brightness alone is not automatically wave amplitude; calibrate the chosen optical measure or use direct height readings. More repeats alone do not necessarily correct a biased method. Protect participants and equipment by this precaution: Keep water away from power supplies and use only teacher-approved low-voltage apparatus.

Waves behind a model breakwater

What a complete response should do

How did this one feel?