By Chris Deziel – Updated March 24, 2022

Wittayayut/iStock/GettyImages

What Is Magnetism?

Magnetism and electricity are two sides of the same coin, a discovery that dates back to the pioneering work of Joseph Henry and Michael Faraday. Electrons possess intrinsic spin, giving each atom a tiny magnetic field. In certain metals, such as iron and steel, the spins of many electrons can be aligned, endowing the material with permanent magnetic properties.

How to Make a Permanent Magnet

Henry’s notebook lists several practical ways to magnetize an ordinary iron or steel rod:

• Rub the rod with a magnet‑charged piece of metal.
• Pass the rod between two magnets, aligning the north pole of one and the south pole of the other along opposite ends.
• Hang the bar vertically and hammer it repeatedly—heat the rod to enhance the effect.
• Use an electric current to induce a magnetic field.

While each method aligns electron spins, the electrical approach is the most efficient and scalable.

Step‑by‑Step: Magnetizing a Steel Nail

What you’ll need:

• A steel or iron rod – a 10‑dimen­sion (10d) or larger nail works great.
• Foot‑to‑two feet of insulated copper wire.
• A power source: a D‑cell battery or a low‑voltage transformer with accessible terminals.

Procedure:

1. Wrap the copper wire tightly around the nail, creating as many turns as possible. Overlap the wire; the stronger the coil, the stronger the induced field.
2. Leave the wire ends free and strip about an inch of insulation from each end for connections.
3. Connect the wire to your power source and power it on for roughly one minute.
4. Turn off the current and test the nail with iron filings. It should attract the filings even after the power is removed, confirming it has become a permanent magnet.

Enhancing Magnet Strength

To boost the magnet’s power, increase the number of coils. Doubling the turns roughly doubles the field strength, but also raises electrical resistance and reduces current. Counteract this by raising the voltage—adjust the transformer setting or use a higher‑capacity battery.

Safety Precautions

Keep the voltage within safe limits to avoid electrical shock. Avoid creating a magnet so strong it sticks to your refrigerator or poses a danger to nearby metal objects.