In an experiment to determine the acceleration due to gravity, one student holds a pencil at arm’s length and drops it. Another student starts a timer when the first student lets go and stops the timer when the pencil hits the ground. They repeat this several times and take an average. Is this a valid experiment, why or why not?

The correct answer is - No, it is not valid because the short distance means there will be a lot of error due to the student's reaction time.

Explanation:

In this experiment to determine the acceleration due to gravity, there may be errors because of the student’s reaction time. The reaction can be late or early than prior reactions.

The other error can be caused by the distance was only at arm’s length throughout the experiment, which means that there was no independent variable that is the difference or change in the distance. This also makes the experiment invalid.