Crazy Craters

The original write-up for this activity was on the Thursday's Classroom website (http://www.thursdaysclassroom.com), which has now gone offline. The activity can be used as a demonstration, a hands-on activity or an in-class lab, and has that "messy factor" which will be sure to get students of all ages involved!

Equipment needed:

• Large aluminum roasting pan
• Cocoa or hot chocolate powder
• Large bag of white flour
• Sifter
• Projectiles of various sizes and densities (balls, rocks, marbles, etc.)
• Rulers
• Garbage bags
• Broom

Note: For a student lab, you will need one set of the
above per group of 4 students.

Method:

1. Cut open a garbage bag and spread on the floor. place the roasting pan on top.
2. Fill the roasting pan about 3/4 full with white flour.
3. Using the sifter, sprinkle a thin, even layer of cocoa/hot chocolate powder on top of the flour.
4. Drop projectiles into the roasting pan and observe the craters, as well as the rims of mountains around the edges of the craters, and the streaks or rays that can fan out from larger craters!
5. This can be repeated as often as you like - just flatten out the flour and add a new top layer of cocoa.

Lab Skills:

• Have the students predict what will happen
• Have the students draw their observations of what happens
• Knowledge of lab variables and controls

Possible labs:

• Vary the height of the dropped objects, and measure the ejecta.
• Vary the diameter of the dropped objects, and measure the ejecta.
• Vary the density of the dropped objects and measure the ejecta.
• Feeling adventurous? Build mountains and hills/valleys, and then bombard them with projectiles!

Things to watch out for:

• Flour can be very slippery on a tiled floor - be sure to clean up well afterward.
• Students are sometimes tempted to throw their projectiles at the pan, increasing the risk of injury in the classroom. Be careful!

Other Classroom Resources

• General Teaching Resources
• Summative Project Ideas
• Canadian Junior Astronomer Program

Originally from http://www.thursdaysclassroom.com
Adapted by the CASCA education Webteam, (2009)