release the marbles at different heights. repeat the experiment several times. tilt the plane at different angles. use two marbles that are the same size.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: A student compared the speeds at which a large and a small marble rolled down an inclined plane. In order to make the findings more reliable, the student should
Possibilities:
- release the marbles at different heights.
- repeat the experiment several times.
- tilt the plane at different angles.
- use two marbles that are the same size.

repeat the experiment several times.