science experiments

Juma's been demonstrating a keen interest in science lately, especially outer space and dinosaurs, so we got him a little science experiments kit for Christmas. These are some of the experiments we've tried:

Soak a raw egg (in the shell) in vinegar for at least 15 hours. Then drop it in the sink and watch it bounce, not break. The shell will become rubbery, due to some chemical change I can't recall off the top of my head.

In a very dark room, smash with pliers (or bite) wintergreen candies and see a spark. Alternatively, rub two sugar cubes together and watch them glow.

Gather several small items (paper clips, penny, wood chip, etc) and see which ones you can pick up with a magnet.

Dissolve lots of salt in a 1/2 cup of water in a quart jar. Place a strip of dark construction paper in the jar, and over the next 3 weeks, watch the salt crystals form up the paper.

Fill a plastic water bottle with very warm water. Replace the cap, and let it stand for 1.5 minutes. Remove the cap, pour out the water, then quickly replace the cap. The bottle will "magically" collapse without you touching it. (There's an air pressure change when the air inside the bottle cools.)