Tuesday, June 28, 2005


We just did one quick experiment from the Book 2 Sciencewise from Critical Thinking Books. My girls loved it. It had a little accompanying story that the king's egg had sunk, and the servant had to bring it to the top of the water, but no one is allowed to touch the king's food.

Here are the basics:
Put an egg in a container (we used a Pyrex 2 cup measuring cup) filled with water. The egg will sink. Without touching the egg directly with their fingers, the experimenters must think of as many ways as they can to bring the egg back up to the surface. Directions say to accept all reasonable solutions. Anna suggested using air bubbled in or a spoon. She tried, unsuccessfully, the addition of pepper, oil, a small amount of salt and dishwashing detergent. She is as I type, trying one last experiment - baking soda and vinegar - knowing from another experiment that the result of mixing the two cause gas to be formed. She's just called from the kitchen - it didn't work.

The "teacher" solution is to add salt slowly while stirring. It will take quite a bit of salt (1/2 a container), but eventually, you'll change the density of the water and the egg will float. Lauren immediately asked was that why it was easier to swim in the ocean than the pool? We discussed natural salt bodies of water (Dead Sea, Salt Lake) and what happens to a cargo ship that goes from salt water to fresh water.

Didn't take much time, but made a lasting impression. I think we'll like this book.

In the back of the book are "projects" that can be done in groups. I am thinking of forming a club of local hs'ers that would come together once in awhile to test their designs. One example is the design of an egg catcher with the egg dropped from a window or ladder.

No comments:


Related Posts Plugin for WordPress, Blogger...

Popular Posts