Question

a student observes that the craters on the moon are different sizes. the student designs an experiment to study the formation of craters. the materials for the experiment are marbles and a pan of flour. the student makes a hypothesis that the size of the craters made on the surface of the flour will depend on the height from which the marble is dropped. some of the steps in the student’s experiment are described below.

1. fill a round pan with flour
2. smooth out the flour in the pan

3.

1. for each trial, measure the size of the crater formed and then smooth out the flour again

which of these is most likely step 3 in the student’s experiment?
a drop the same marble from different heights into the pan of flour
b drop marbles of different masses from the same height into the pan of flour
c drop marbles of different sizes from different heights into the pan of flour
d drop a single marble one time into the pan of flour

Explanation:

The experiment tests how drop height affects crater size, so only the height should change (independent variable), while the marble (size, mass) stays constant. Step 3 must be the test action that manipulates height while controlling other variables.

Answer:

A. Drop the same marble from different heights into the pan of flour