Parabola Experiment


The hypothesis was that the ball would fall in a parabola such as the ones that Galileo described. If that was indeed the case, then we would be able to assume that Galileo had indeed performed these experiments.


Inclined Plane

Camera Stand

Steel Ball Bearing

Butcher paper

Carbon Paper

Tape Measure



1. Build inclined plane. (See inclined plane experiment.)

2. Find the angle of the plane.

3. Set up the paper on which the ball will fall.

4. Measure the distances that the ball would roll along the plane and the height the ball would fall after leaving the inclined plane.

5. Roll the ball five times from each distance, using the carbon paper to mark the impact location.

6. For trial two, we used a different angle, and otherwise did everything else the same.

7. For the parabola tracing, we collected boxes and stacked them up. We let the ball roll five times for each height, marking the distances on the same sheet of paper.

8. We measured the distances on the papers and analyzed the data.


We attempted to build a deflector made of Play Doh at the bottom of the inclined plane. However, trial runs showed that the ball did not roll along the deflector, but instead jumped over it. We hypothesize that this is because Galileo used angles of no less than 30 degrees, while our greatest angle was 13.4 degrees. At a larger angle, the downward component of motion of the ball is sufficient to keep it in place along the deflector. At our angle, the downward component of the motion was not sufficient to do so.


Last Revised April 17, 1995.
Martha Turner, Sharmaine Jennings