A fixed marker is raised slightly above a horizontal ruler. A camera can be moved around the marker without moving the ruler. Available equipment and procedure options: Use a ruler, raised marker, protractor and camera; compare every reading with the overhead reference. Design an investigation of how the viewing angle from directly above affects the difference from the overhead scale reading. 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 viewing angle from directly above; measure the difference from the overhead scale reading. Predict Larger viewing angles should produce larger apparent position errors. Keep marker location, marker height above the ruler, ruler and camera focus constant, repeat each setting, and use the evidence to test the prediction. State a testable research question linking the viewing angle from directly above to the difference from the overhead scale reading, rather than asking vaguely which arrangement is best. A suitable prediction is: Larger viewing angles should produce larger apparent position errors. Justify that prediction scientifically: The marker and scale are in different planes, so an oblique line of sight intersects a different scale position. 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: Use a ruler, raised marker, protractor and camera; compare every reading with the overhead reference. Record quantities with units before calculating any derived result. Keep marker location, marker height above the ruler, ruler and camera focus 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: Angle and camera distance can change together; use a marked arc centred on the marker. More repeats alone do not necessarily correct a biased method. Protect participants and equipment by this precaution: Secure the camera stand and keep its feet out of walkways.

A ruler viewed from the side

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