Question

Use the table of criteria for an investigation to answer the question.

Effect of Object Mass and Drop Height on Gravitational Study
Object To Be Dropped Drop Height (meters)
10-gram ball 5
5-gram ball 8
18-gram ball 10
A student designs an investigation to study the effect of gravity on objects on Earth. He will use the criteria shown. How can the student improve the investigation?

(1 point)

by dropping the balls from the same height

by finding balls made from different materials

by measuring the circumference of the balls

by using balls that are the same mass

Answer 1

Answer: by dropping the balls from the same height.

Reason: to make it a fair test you must change only one variable at a time. The current plan varies both mass and drop height, which confounds the results. Keeping height constant isolates the effect of mass (or conversely, keep mass constant to test height).