Magnetism

1. I use floating magnets to demonstrate the forces (attraction = opposite poles & repulsion = like poles) of magnetism. I take two of the same magnets and put them on the top of the overhead projector to cast a shadow on the screen to show what happens to the magnetic field as the distance increases and decreases. I pass the magnets around the class so that the students can experience the magnetic forces of attraction and repulsion.

2. We also make magnets by magnetic induction by laying a screwdriver next to a magnet in order to align the magnetic domains, and stroking the screwdriver in one direction witha permanent magnet. Then we randomize the magnetic domains by heating and banging the temporary magnets. Students are able to see how the magnet loses its magnetism when we randomize the domains.

3. Another temporary magnet that we make is an electromagnet. The students are made aware that a current carrying wire has a magnetic field that surrounds it. (We can show that by using a compass to detect the magnetic field.) We use a source of voltage, like a battery, a wire, and an iron nail. We are able to pick up paperclips and my car keys, and then drop them off in a different area when we open the circuit. In order to increase the strength of the magnetic field we put more coils around the nail, we add more nails, and we increase the voltage in order to increase the current.

Students absolutely love seeing how these scientific concepts can be applied. This makes something that is abstract, concrete and helps them to understand, and enjoy coming to class.