A 9-volt battery is an ideal battery for magnetising a small screwdriver. It's small and easy to move around; you can even tape the battery to the handle of the screwdriver. Importantly, no other battery, that's relatively inexpensive, produces nine volts. Magnetising a small screwdriver is a great way to introduce magnetism and basic physics to your children while providing entertainment and at the same time making a useful magnetic device.
Wind uninsulated AWG 18-gauge wire tightly around the shaft of the screwdriver. Start about one-half inch from the handle. Leave three inches of wire free at the end where you start winding.
Stop winding the wire when you get one-half inch from the tip of the screwdriver. Cut the wire with wire cutters, leaving enough wire to reach back up to the handle.
Place a 9-volt battery next to the screwdriver handle, ensuring the battery terminals face toward the shaft of the screwdriver. Wrap electrical insulating tape around the screwdriver handle and the battery to hold the battery firmly on the handle. Use scissors to cut the tape.
Wrap the end of one wire near the handle around one of the 9-volt battery terminals. Wrap the end of the other wire around the other battery terminal. Use electrical insulating tape to hold the wires in place. Your screwdriver will be magnetised.
Disconnect one of the wires from one of the 9-volt battery terminals to stop the flow of electricity. You will find that your screwdriver still remains magnetic for a few days. The longer you leave your battery connected to the wires, the more magnetic your screwdriver gets.