Wednesday, October 9, 2013

Chocolate Rock Cycle

Now, to put all this information together in the Rock Cycle! There are lots of ideas online about how to simulate the rock cycle. You can use crayon shavings, but we used three types of baking chips---chocolate chips, peanut butter chips, and white chocolate chips.
You can start the cycle at any point. We started by "weathering" various rocks and minerals (the baking chips) into smaller sediment. We used graters, paring knives, and a microplane grater to do the weathering. You want some very small pieces, and some larger pieces, of each type of baking chip.
Sprinkle a little bit of each type of sediment onto a piece of foil. Wrap it up tight and then add some pressure. You can squeeze it tightly between your hands (this adds a bit of heat) and then stand on it. Put a book on top to distribute your weight evenly.
Unwrap the foil to see your sedimentary rock! Each person's "rock" will be a bit different, based on the rocks and minerals that it is composed of. Be careful when handling these rocks because they are quite fragile.
Now add more heat and pressure to make a metamorphic rock. We re-wrapped our rocks tightly in the foil and then floated them on some hot water for 10 seconds or so. (You don't want to melt the chocolate completely.) Press the foil between your hands again to add more pressure. Then put the rock (in its foil packet) into the refrigerator to harden for several eons (10 minutes or so). :)  Unwrap it to see your metamorphic rock! You can observe, at this point, that some of the "minerals" making up the rock are more melted and disfigured than others. This is true to nature, as different minerals have different melting points and will also re-crystallize at different temperatures.

Igneous rocks are next. Take your metamorphic rock, re-wrap it in foil, and float it for a longer time on some hot (even boiling) water.
Sometimes a little bit of water leaked into our foil "boats." It's okay.
Unwrap, take a toothpick, and stir the melted rock and minerals around. This is "magma," and you are creating convection currents in it.
Refrigerate the rock again until it's hard. Now you have an igneous rock! The minerals are still present, but you can no longer see them as individual components because they all melted together in the magma.

We LOVED this activity. It is simple and yet it models the process so well!
Sebastian's illustration of the rock cycle

No comments:

Post a Comment

Related Posts Plugin for WordPress, Blogger...