Question

students design an investigation to study the effect of different surfaces on the speed of a ball rolling down a ramp. which of these is the independent variable?

time to roll down the ramp

mass of the ball

diameter of the ball

kind of surface on the ramp

Explanation:

The independent variable is the factor that is deliberately changed in an experiment to observe its effect on the dependent variable. Here, students are changing the surface of the ramp to study its effect on the ball's speed. So the surface of the ramp is what is being manipulated.

Answer:

kind of surface on the ramp