Making Craters

In this experiment you get to look at how craters form on the moon or other celestial bodies. You drop or throw rocks at a pan of flour and cocoa powder to see what kind of impact is left by what kind of rock from what velocity and angle. Your “craters” can then be compared to those on the moon.

It is important to be aware of everyone around you and of breakable objects when doing this experiment. Use care, because throwing rocks could hurt or damage people or objects. You might consider doing this experiment outside.

• Pan or tray (ideally about two inches deep)
• Rocks or balls

• Flour and cocoa powder (sand or dirt could easily replace either or both of these)

1. Fill your tray with about two inches of one material, for example flour.
2. Cover the tray with your second material (coca powder)
3. Drop a rock onto the tray. Remove it and se what kind of crater it formed. Is there an indentation? A rim? Did flour or cocoa powder splash out of the hole?
4. Try again, using a different rock (or ball).

1. Now toss the rock at the tray at an angle, and see if/how the crater is different.

You might need to relay cocoa powder on top if the two layers get mixed up. The cocoa powder gives you more information about the very top level.

You can look at images of comets on wikipedia or other websites.

(Image from Wikipedia)

Q: When comparing this experiment to craters that result when an asteroid hits a planet or moon… What did the flour and coca powder symbolize? What were the rocks?

A: The surface (dirt/rock) of the planet. The rocks were the asteroids.

Q: There is a hole now. Where did the material that used to be in that hole go?

A: Some material got spit out and flung a distance – you can probably see this from the coca powder that spread around. Most of the material was pushed down, out and up, and formed an elevated rim around the hole.

Q: Are planets really made out of flour?

A: Not the ones we know!

Q: What do you think would change if we used dirt or sand or rocks instead of flour to model the surface of our planet?

A: Because these have more density than flour and are often stuck together more, it would require more force to make craters. You should note that when asteroids hit planets, they probably hit with much more force than you could throw a rock with.

You could also discuss how craters look similar to, and different from, ripples in water if you drop a rock in.

See discussion (above) and Wikipedia for more information on craters.

You can throw away the kitchen powders in normal trash, while rocks, sand and soil can go in your yard or back where you found them.

Wikipedia Crater Image

None.