Safe Science Crafts for Children by Ashley Hardway

Electromagnets are quite easy to build at home. All you would need in order to build one is: a “D” sized battery, copper wire, and an iron nail.
By connecting the copper wire to the positive terminal, wrapping it around the nail three-quarters of the way down and connecting the end to the negative terminal, the iron nail becomes an electromagnet. This is caused by the electrons arranging the molecular structure in the nail to become attracted to other objects that are also made of iron such as thumb tacks. Some of the world’s most powerful locks are electromagnetic. Here is a diagram to help with your efforts.

This is one of the most popular of projects with children that love to make a mess. Using the candy “Mentos,” you can force a geyser-like eruption that can reach a great distance. The popular theory behind how Mentos cause this eruption involves the tiny pores along the surface of the candy. These pores help separate dissolved carbon dioxide molecules from the Diet Coke at a rapid pace allowing the bubbles to expand at a great velocity. Others believe it must have to do with a component in Diet Coke interacting with a chemical within the candy itself – since not all carbon dioxide-laden sodas have the same effect. Start with a two-liter bottle of Diet Coke at room temperature. Quickly add a few Mentos and stand back. This is best done outside. If you want to see some wild versions of this experiment search “Diet Coke Mentos” on YouTube.