By Darby Stevenson
Updated Mar 24, 2022
Electromagnets are the workhorses of modern technology, from MRI machines to electric motors. Unlike static magnets, they can be turned on and off with an electrical current, giving engineers precise control over their magnetic field. By carefully arranging the polarity of two small electromagnets, you can make them repel each other—an effect that’s both fascinating and useful for hands‑on demonstrations.
Below is a straightforward, safety‑first method to construct two repelling electromagnets using everyday items. The process illustrates fundamental physics principles while remaining accessible to beginners.
Wrap the insulated copper wire tightly around one nail, leaving about 3–4 inches of free wire at each end. Use a steady, even spacing so the coil is uniform. Once finished, cut the wire with wire cutters.
Bend the free ends of the wire to form hooks and attach them to the positive and negative terminals of the first battery. Note which end of the nail is connected to which terminal; this determines the nail’s polarity.
Repeat the winding and connection process for the second nail, using the same battery polarity (positive to the same side of the nail as before, negative to the opposite). This ensures the two electromagnets share the same orientation of magnetic poles.
Place the two nails on a non‑metallic surface so that their tips point toward each other. When both batteries are live, the nails’ like poles will face each other, causing a clear repulsive force. The effect is subtle but unmistakable, demonstrating the fundamentals of magnetic fields.
Safety Tips
With this simple experiment, you can explore electromagnetism, test your understanding of polarity, and gain confidence in building basic electronic devices.
