On March 11, staff members from the Discovery Centre were on Discovery Channel’s Daily Planet show, demonstrating just what a crater looks like and how it works – the best part is that this is also an experiment you can try at home! All you need is space for a mess (as always), corn starch, cocoa and some “asteroids” and “comets.”
The simple setup can be done in the kitchen: create a thick layer of cornstarch and cover it with a thin layer of cocoa (or any dark, finely ground powder). The following embellishments add to the experiment, but the crater really only requires a layer of cornstarch covered with enough cocoa to darken the surface. You can hold the mixture in a container or on a cookie sheet – this will help with cleanup, and even allow you to try deeper layers of starch. You can also use other top coats: cocoa is common in kitchens, but powdered tempera paint comes in vibrant colours and works just as well (and is still washable). Packing the starch down changes the shapes it forms. You can even add a layer of salt at the bottom for even better craters.
In the real world, impact craters are formed when something falls to the Earth (or the Moon, or other big things in space) with a lot of momentum – meaning it is going really fast, is really heavy, or both. This makes a big dent in the ground, and also throws lots of dirt and rock out from the impact site – this is called “ejecta.” For our craters, the starch forms a dent just like the Earth does, and the cocoa gives a colour to contrast with the ejecta, and sometimes even cracks in the surface of your starch “planet” – all just like real craters.
The experimentation comes from trying different angles and speeds of impact and different objects. Try varying the thickness of your starch layer too; we recommend somewhere from half to the full thickness of the objects you plan on using, but that’s just a starting point.
The TV segment aired on Monday’s Daily Planet, but the winning science centre will be announced from the International Space Station on Friday, March 16th by Canadian astronaut Chris Hadfield. Check out our clip on their website, try some craters at home and don’t forget to come wish us luck over March Break!