Floats

What floats in saltwater and sinks in fresh water?

Me and some ppl in my class are doign a project. We need something that floats in saltwater and not in fresh water (and no, we can't use an egg)

Public Comments

1. How about a block of salt, soap, or a brick???
2. A small pill bottle containing just enough metal, or coins.
3. ummm....i am not 100% sure but does ice? You would need to check it out. Its been years since I went to school. It has to do with density and the object being lighter than water and heavier than the salt and water being mixed together. I guess it would need to be something thats sealed, has a liquid, almost gassy or airy inside. Like a grape??
4. A balloon full of fresh water. The guy who suggested a bottle with the right number of coins in it also has the right idea. Its called a hydrometer, but a balloon full of fresh water will be simpler. Depends on what you have on hand. http://en.wikipedia.org/wiki/Hydrometer
5. SALT WATER IS HAVING A SPECIFIC GRAVITY MORE THAN ONE WHICH DEPENDS ON HOW MUCH SALT CONCENTRATION YOU HAVE. PLACE A SMALL PIECE OF ALUMINUM --IT SHOULD SINK IN FRESH WATER BUT WOULD FLOAT IN 10-15WT % SALT WATER. GOOD LUCK.
6. almost anything, most people would teach kids to learn how to swin in saltwater because saltwater has a higher density than freshwater.
7. Here's an idea: Take a small jar with a cover, fill it partially with water, and cover it tightly. Then put it in a larger basin of water. Depending on how much air is in it, it will either float or sink. Try to get the air/water mix to the point whereit just barely sinks in fresh water. Then add salt and see if it floats.
8. find something that is less dense than saltwater and more dense than fresh water