To illustrate why boats made of metals float despite their weight, have the student construct a boat out of aluminum foil or use an empty soda can with the opening taped over. Take a large bowl and place a strip of tape about halfway to the top. Fill the bowl to the tape. Place a heavy metal object like a piece of silverware or a nail into the bowl and watch how the object sinks. Remove the object. Next, place the boat or can in the bowl. The weight of the boat/can will cause the original water line (that was level with the tape) to rise. Place another strip of tape at the new water line. Ask the student why the boat floated even though it was made of metal and the other metal object sank. Explain how the curved bottom of the boat displaces a certain amount of water and that the water weighs more than the boat does. Add dried beans to the boat a few at a time to see how long it takes the boat to sink.
Explain about the magnetic properties of the Earth and how most metals are magnetic. Explain how magnets have poles that attract and repel and about protons, neutrons and electrons. Gather common metals such pushpins and paper clips. Using a strong-poled magnet, demonstrate the properties of magnets. Next, gather some non-metal items and show how they are not magnetic.
Explain about how metals can conduct electricity and how electricity is both helpful and dangerous. Wrap a piece of wire around a penny, leaving a tail of about an inch, do the same with a nail. Stick the edge of the penny into a lemon that has been cut in half. Do the same with the nail, ensuring it is close to the penny but not touching. Attach a voltmeter to the nail and penny, using the nail as the negative and the penny as the positive. The voltmeter should produce a reading. Alternatively, the lemon battery can be used to power a clock, as well.
Explain how metals are beneficial to our body, focusing on iron and how it is in some of our foods. Place two different kinds of cereal in Ziploc bags, one containing extra iron, and crush into a powder. Add an equal amount of water. Tape a magnet to a spoon. Use the spoon to stir the cereal for at least five minutes, wiping the spoon with a white coffee or tea filter. Only pieces of iron should be on the coffee filter when you are finished and should be viewable with a magnifying glass.