Question 4
Make an electromagnet with insulated copper wire wrapped tightly around an iron nail, leaving a few centimetres free at each end and stripping the insulation from both ends. Connect the wire ends to the two terminals of a 9 V cell; an optional switch can turn the circuit on and off. Disconnect promptly after each test: the wire can get hot. Once the circuit is connected, your electromagnet should be ready to use. Test it by bringing it close to some small metal objects. What happens?
