Look closely at the moon and you’ll see it’s covered with craters — some of them billions of years old. Ever wonder what caused these depressions in the moon’s surface?
The moon’s very thin atmosphere allows objects like meteorites to strike the surface, making impressions called impact craters. Craters vary depending on a striking object’s size, shape, and speed. Try this experiment at home to see how the moon got its signature look.
- 13×9-inch or larger plastic tub (use any shallow pan or tray; a small kiddie pool works, too)
- 5-pound bag of flour
- 8 ounces cocoa powder
- 3-5 balls in various sizes (golf balls, marbles, tennis balls, ping pong balls, etc.)
- 1-inch angular or odd-shaped rocks (at least two)
- Take your materials outside or to an easy clean-up location and fill your tub with about 3 inches of flour.
- Sprinkle a thin layer of cocoa powder onto the surface.
- Now go make craters! Choose any ball to start. Stand so that your ball is about 3 feet (1 meter) above the container, and drop it into the cocoa/flour.
- What do you observe?
- Make a prediction about what will happen with the other balls, and drop them the same way.
- What happened this time? Is it what you expected?
- Now try dropping the angular rocks. Did anything change? Does it look different?
- Remove your objects from the flour with the tongs. If you want to try more craters, just dust off your objects, sprinkle more cocoa on top of the flour, and start again!
Here, we are experimenting with objects of different sizes and shapes to see what their impact craters look like. Everything from the shape and depth of the crater to the “splatter” of materials is affected by the characteristics of the impacting object. For a challenge, try dropping your objects from different heights or different angles. You may also want to try adding a third layer of material (like cookie or bread crumbs) to see how your results change.
Did you know?
The Earth’s dense atmosphere typically causes meteorites and other objects to burn or break up before they can strike the surface. Occasionally, a few objects make it through. One of the best-known impact craters on Earth, Meteor Crater, is located near Flagstaff!
Your family can learn more about space, our solar system and the universe at the Arizona Science Center’s new “Cosmic Playground” exhibit through Sunday, Jan. 13, 2019.
Sari Custer is a lifelong science junkie, Chief Curiosity Officer at Arizona Science Center, and mom to daughter Carson (4). Follow her on Twitter and Instagram @SariOnScience.