Question

A student is measuring the effects of an electric circuit on a compass, and he is testing to see if increasing the current will cause the compass needle to change its direction faster. He does one trial using a 9-volt battery and another trial using a 1.5-volt battery. He takes accurate data. Based on good experimental design, which would improve his experiment?

He should repeat the test with three additional batteries of varying voltages to demonstrate the reproducibility of results.

He should use batteries of the same voltage but from different manufacturers, to show he has used different variables.

He should add a nonworking compass to act as a control.

He should use only one battery but do several trials, using different circuit designs to ensure he has appropriate test groups.

Answer 1

he should repeat the test with three additional batteries varying voltages to demonstrate the reproducibility of results

Answer 2

Option A

Step-by-step explanation:

A good experimental design include several trial in order to reach at an accurate and precise result.

Here the experiment is conducted only two times where once a battery of 9-V is used and then a battery of 1.5 V is used.

It would be good to conduct the same experiment with the same set up by using batteries of varying voltage in order to determine the effect produced on a compass if it is placed near an electric circuit.

Hence, option A is correct