Skill & Curiosity

DIY electromagnet experiments

CostFree to Low

Includes: Enamelled wire, iron nails and bolts, 9V batteries, a galvanometer. Example: Enamelled wire costs €5-10; a galvanometer €15-30.

What it is

Wrap wire around an iron nail, pass a current through it, and the nail becomes a magnet. Cut the current and the magnetism vanishes instantly. That on-off relationship between electricity and magnetism is one of the four fundamental forces of nature, and you can hold it in your hand for the price of some wire and a battery.

DIY electromagnet experiments are hands-on investigations of electromagnetism, the force governing motors, generators, speakers, hard drives, and much of modern technology, using coils of wire, batteries, iron cores, and basic components to explore how current creates magnetic fields and how magnetic fields create current. Electromagnetism is the least intuitively understood of the fundamental forces, which is exactly why feeling a coil warm as current flows, watching iron filings snap into field patterns, and feeling the force between electromagnets change with current builds genuine understanding of something otherwise entirely abstract.

The experiments scale steadily. The core build is a nail wrapped in 50 to 100 turns of enamelled copper wire connected to a 9V battery, strong enough to pick up small iron objects, and varying the turns, current, and core material lets you measure how each affects the strength. From there it extends to an electromagnetic relay, an electromagnet that switches another circuit and the basis of every pre-transistor computer, to induction, pushing a magnet through a coil to generate a measurable current, and to a simple spinning motor. The one material tip that matters most is to use enamelled magnet wire rather than ordinary insulated wire, because the thin enamel lets you wind hundreds of turns tightly without short circuits, which dramatically boosts the field for the same current.

How it works

The wire you choose changes everything, and using the wrong type is why a first electromagnet barely works. Use enamelled copper wire, often sold as magnet wire, not ordinary insulated hookup wire, because the thin enamel coating lets you wind hundreds of turns tightly against each other without the windings shorting. More turns packed close means a far stronger field for the same current, which is the whole principle.

The core experiment is straightforward. Wind 50 to 100 turns of enamelled wire neatly around an iron nail, sand the enamel off the last few millimetres of each end so you can make electrical contact, and connect those ends to a 9V battery. The nail becomes a magnet strong enough to pick up paperclips and small iron objects. Then vary one thing at a time, more turns, higher current, a different core material, and observe how each changes the lifting strength, which turns a demonstration into a real investigation. From there the experiments extend in revealing directions. An electromagnetic relay uses the field to switch a second circuit, the basis of every pre-transistor computer. Pushing a permanent magnet through a coil generates a measurable current on a galvanometer, demonstrating induction, the reverse effect. The coil will get warm in use, which is itself a lesson: resistance turns some electrical energy into heat, exactly why computer chips and electric heaters get hot.

Benefits

Electromagnetism Understanding Physics Investigation Skills Foundation for Electronics Motor and Generator Principles Understanding of Modern Technology Invisible Force Made Tangible

What you need

Here's what to gather before you start. The essentials are marked.

Some links below are affiliate links. As an Amazon Associate, trylii.com earns from qualifying purchases, at no extra cost to you.

Enamelled copper wire

Iron nails and bolts

9V batteries

SuggestedAffiliate

9v battery

View on Amazon

Galvanometer or multimeter

SuggestedAffiliate

Multimeter

View on Amazon

Permanent magnets

Iron filings for field visualisation

FAQs

How do I make a basic electromagnet?

Wrap insulated wire around an iron core and pass current through it. A nail wound with enamelled copper wire, connected to a battery, becomes a working electromagnet in minutes. The current creates a magnetic field, and the iron nail concentrates it. More turns of wire and more current both strengthen the magnet. It is one of the most satisfying first experiments because the result is immediate and genuinely useful to understand.

Why does my electromagnet get so hot?

You are running too much current through too little wire resistance. Connecting a coil directly across a battery with low resistance draws a large current that heats the wire fast, which is normal but can become dangerous. Adding more turns of thinner wire increases resistance and reduces the current, or you add a resistor in the circuit. Never leave a hot coil connected, and never short a battery directly through a tiny coil.

What makes one electromagnet stronger than another?

Three things: number of wire turns, amount of current, and the core material. More turns and more current both increase the magnetic field directly. A soft iron core concentrates the field far better than air or aluminium, which is why the nail matters. Doubling the turns roughly doubles the strength at the same current, so neat, tight, numerous windings beat a few loose ones every time.

Can I make one strong enough to lift real weight?

Yes, within limits and with proper care. A well-wound electromagnet on a good iron core, driven by a suitable supply, lifts surprising amounts, but reaching real strength means more current and more heat, which is where it gets risky. Bigger electromagnets need a current-limited power supply rather than a raw battery, and they demand respect because the wire heats quickly and the magnetic forces become genuinely strong.

What's the difference between this and a permanent magnet?

An electromagnet only works while current flows, and that is its superpower. Switch off the current and the magnetism vanishes, which lets you turn the force on and off, control its strength, and reverse its poles by reversing the current. A permanent magnet is always on. That switchability is exactly why electromagnets run motors, relays, and lifting magnets where a permanent magnet simply could not do the job.

Is it safe, and what should I watch for?

Generally safe with low-voltage batteries, but watch heat and current. The main hazards are the wire overheating, the battery overheating if shorted, and at higher powers the magnetic field affecting nearby electronics or magnetic media. Use sensible currents, disconnect when not observing, and never build a high-power version without a proper current-limited supply. Keep it away from phones, cards, and anything with a magnetic stripe or sensitive electronics.

⚠️ Coils can overheat quickly and shorting a battery through one is a burn and fire risk. Use low voltages, never leave a coil connected unattended, and use a current-limited supply for anything powerful.