October 7, 2009

Science Lab

Our current science lab is finding out how ice can weather rocks. You put some water into a balloon (about the size of a tennis ball) and tie it off. You then coat the outside of the balloon with plaster of paris (store bought or homemade - flour & water mixture) and let it dry completely to make a rock. Then you place your "rock" in a bowl and into the freezer overnight. The following morning you check on your "rock" and see what happened to it when the water inside froze. This is what happens to rocks when water seeps into the cracks & holes and then freezes when the temperature drops.

Here is Morgan covering her balloon.
Here is Alex covering his balloon.
We started this experiment on Monday. Unfortunately, our homemade plaster mixture was too thin and would not stay on our balloons long enough to dry. So this morning we tried again. We made the mixture thicker and it seems to be doing much better.

Here is Morgan's balloon.

Here is Alex's balloon.
Once they dry (we put them in the sunny, kitchen window) we will put them in the freezer and check on them tomorrow. What do you think will happen?


At 8:55 PM, Anonymous Ruby said...

Love it! How simple yet what a great learning experience. Where do u get your plaster from? Could you buy it in the craft section at Wal-Mart?

At 9:14 PM, Blogger Kelly said...

Ruby, we made our's at home with flour & water. The first day we made it too thin and it slid off the balloons. Today we made it thicker and it did much better. The "rocks" are in the freezer. I believe the craft section of Wal-Mart or some place like Hobby Lobby should have it.


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