4. varying impact velocity

The problem of this experiment will be something like “I want to find out if high velocity impacts produce bigger craters than low velocity ones.”

Again, think carefully before you set up your experiment. For instance, will doubling the impact velocity produce a two times bigger crater? What is big: diameter, area, or volume of the crater? Then think of a clever hypothesis.

Materials:

1-8

9.  2-metre graduated ruler, tape measure, or other height-measuring device (can be longer if you wish). You will need this to measure the height from which you drop the projectiles. You can build something similar to the diagram from bits of wood lying around. The platform is important since it ensures that you launch your projectile with zero starting speed every time. See illustration.

Repeat the experiment three times for different drop heights, doubled each time, e.g. 25, 50, 100 and 200 cm. Use the same projectile throughout. Measure diameters and depths of the craters as well as number and length of ejecta rays and be alert for changes in shape.

Record your observations in a table as usual and construct graphs (crater diameter and depth against drop height).

Does doubling your drop height also double the impact speed? Is there a way to measure the speed, or calculate it from the drop height?