A class uses a shallow ripple tank or a calibrated wave simulation to investigate a wave model. Available equipment and procedure options: Rotate the straight boundary relative to incoming plane crests and trace normals on a photograph. Design an investigation of how the angle of incidence on a shallow-water boundary affects the angle between transmitted wave direction and the normal. 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 angle of incidence on a shallow-water boundary; measure the angle between transmitted wave direction and the normal. Predict The transmitted direction should bend towards the normal when waves slow down. Keep depths on each side, source frequency and camera geometry constant, repeat each setting, and use the evidence to test the prediction. State a testable research question linking the angle of incidence on a shallow-water boundary to the angle between transmitted wave direction and the normal, rather than asking vaguely which arrangement is best. A suitable prediction is: The transmitted direction should bend towards the normal when waves slow down. Justify that prediction scientifically: The part of a crest entering shallower water first slows first, rotating the wavefront. This is a hypothesis to test, not a result that the experiment must produce. Use 0°, 15°, 30°, 45° and 60° as the planned independent-variable settings. Measure the response using the supplied equipment: Rotate the straight boundary relative to incoming plane crests and trace normals on a photograph. Record quantities with units before calculating any derived result. Keep depths on each side, source frequency and camera geometry 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: Angles measured to the boundary instead of the normal reverse the intended comparison. 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.

Turning waves at a depth boundary

What a complete response should do

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