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Science Projects for Kids on Electromagnets

An electromagnetic science fair project can demonstrate how a metal object's magnetic field increases when an electric current runs through it. An increased magnetic field around a nail, for example, can enable it to pick up objects that would ordinarily be too heavy for it to lift. Such an electromagnetic device, known as a solenoid, generates a powerful magnetic field by aligning smaller magnetic fields within the nail in one direction.

Building an Electromagnet
- Wrap a long strand of thin copper wire around a long nail. The tighter the coils and the more concentrated you make them around the nail, the stronger the nail's magnetic attraction will be. Don't wrap either end of the wire within this coil, and leave plenty of wire to attach to the other elements of this circuit. Tape the end of the wire that leads from the point of the nail to the negative end of a D battery.
Adding the Charge
- Tape a small piece of wire to lead from the top of the D battery to the negative end of a second D battery. Tape another small piece of wire to the positive end of the second battery and connect the other end to a terminal on the bottom of a DC-current-specific switch, preferably a "knife" type switch. Connect the end of the wire that leads from the head of the coiled nail to the other terminal of the switch. The switch demonstrates how the circuit and electromagnet function when powered on versus how they work when the switch is in the off position. With the switch turned on, you have a closed-circuit electromagnet.
Testing the Electromagnet
- To test the electromagnet, tun the switch on and touch the pointed end of the coiled nail to a pile of paperclips. If the circuit is connected correctly, then the paper clips will be instantly attracted by the powerful magnetic field generated by the circuit. This is a result of the magnetic fields in the nail being aligned in one direction, making one strong field. With a number of variables involved in creating this electromagnetic field, you can experiment with the components of the circuit to demonstrate how it works..
Independant/Dependant Variables of the Experiment
- The battery strength of the circuit is an independent variable. What happens if you add a third battery to the circuit? Hypothesize what effect manipulating this variable will have on the number of paper clips the electromagnet can pick up, which is a dependent variable. There should be a proportional relationship between the strength of the electromagnet (the strength of battery power) and how many paper clips it can pick up. Experiment with picking up other metal objects and see how you need to modify the circuit for each. You also can see what results from varying the concentration of the coil around the nail.

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