Electromagnet Experiment for Kids: Wrap a Nail, Lift Metal

A magnet with a switch. That is the thing worth noticing, and children usually notice it before you point it out: this electromagnet experiment for kids makes a magnet that stops being a magnet when you let go of the wire. Fridge magnets cannot do that. The build takes fifteen minutes, works on the first attempt if you have the right wire, and turns into a real experiment the moment you start counting turns and paperclips instead of just picking things up. The surprise at the end is that the nail matters more than the coil.

Key Takeaways

• You’ll wind enamelled copper wire round an iron nail, power it from one D cell, and lift paperclips.
• It teaches that moving charge makes magnetism, and that an iron core multiplies the effect enormously.
• Best from about age 7 for the build, from 10 for the turns-versus-clips graph.
• What usually goes wrong: using bare or badly stripped wire. Each turn shorts to its neighbour and you get almost no magnet.
• Everything here runs on one 1.5-volt cell. Never a wall socket, never a mains adapter, never a car battery.

What You’ll Need

Item	How much	Where to get it	If you don’t have it
Large iron nail	1–2, 100 mm, plain steel	Hardware store	A long bolt. Not stainless, not aluminium, not brass
Enamelled copper wire	5 m, 26–28 AWG (0.3–0.4 mm)	Hardware or electronics shop; motor rewinding shops sell it by weight	Salvage from a dead transformer, loudspeaker or motor
D cell, 1.5 V	1–2	Supermarket	AA works, more weakly. Avoid a 9 V block: it overheats and dies fast
Battery holder with leads	One	Electronics shop	Tape the wires to the terminals, firmly
Paperclips	50, all the same size	Stationery drawer	Steel pins, or small nails
Sandpaper	A scrap	Toolbox	A nail file, to remove enamel from the ends
Masking tape	A little	Drawer	—
Pencil or plastic straw	One	Pencil case	Needed for the no-core comparison

Time: prep 10 min, experiment 30 min, cleanup 5 min Cost: around 8 dollars if you need wire and a holder Mess level: low

Do the Experiment: An Electromagnet Experiment for Kids, Step by Step

Step 1 — Sand the enamel off both ends of the wire

Enamelled wire looks like bare copper but carries a clear varnish. Sand the last 2 cm of each end until it is bright pink all the way round. Skipping this gives you a coil that does nothing and no clue why.

Step 2 — Wind 50 turns, counting out loud

Start 2 cm from the nail’s point, wind tightly and neatly in one direction, keeping turns touching but not overlapping. Count aloud so the number is real. Tape the start and finish so nothing unwinds.

Step 3 — Predict, then connect and dip

Ask how many paperclips 50 turns will hold. Write the guess down. Then connect the wire ends to the cell and dip the nail’s point into the pile.

What you should see: clips jump onto the point and hang in a chain. With 50 turns on a 100 mm nail and a fresh D cell, expect somewhere between 3 and 8 clips. Disconnect one wire and almost all of them drop.

Step 4 — Rewind to 100 turns and then 200, measuring each time

Lift the clips three times at each turn count and record the best result. Disconnect between tests and give the coil twenty seconds. The wire and cell get warm, and heat changes the answer.

What you should see: roughly double the clips going from 50 to 100 turns, and noticeably less than double going from 100 to 200. The returns diminish, which is a result worth having rather than a problem.

Step 5 — Do the control everybody skips

Unwind 100 turns from the nail and wind the same wire onto a pencil or a plastic straw instead. Same cell, same turns, same current.

What you should see: almost nothing. One clip at a push, usually none. The coil alone is a feeble magnet, and the iron nail is doing most of the work. This single comparison is the most important two minutes of the afternoon.

Step 6 — Test whether the nail stays magnetic

Put the coil back on the nail, power it up, lift a clip, then disconnect the cell and watch.

What you should see: the chain drops but the nail will usually still pick up one clip, weakly. That leftover is residual magnetism, and a hardened steel nail keeps more of it than a soft iron one. Tap the nail hard on the table and test again: the remnant mostly disappears.

What’s Actually Going On

An electric current produces a magnetic field around itself, circling the wire (HyperPhysics on the magnetic field of a current). The link between current and magnetic force is so fundamental that it was used to define the ampere itself for most of the twentieth century, before the 2019 redefinition of the SI units (NIST). Wind the wire into a coil and the contributions from each turn add together inside it, giving a field along the axis whose strength is proportional to the current and to the number of turns per unit length (HyperPhysics on solenoids). That is why turns matter: 100 turns packed into the same length as 50 gives twice the field. It is also why packing them tightly and in one direction matters, because a turn wound backwards subtracts from its neighbours rather than adding.

Then the iron. Iron is ferromagnetic, which means its atoms carry magnetic moments that line up with an applied field and reinforce it, so the field inside the nail becomes far larger than the coil alone would produce. That is the whole content of step 5, and the factor involved is large enough that a coil on a pencil struggles to hold a single clip while the same coil on a nail holds eight. The nail is not a passive former. It is an amplifier.

Two honest complications. First, the relationship between turns and paperclips is not a straight line. Field rises with turns, but the force on a clip rises faster than the field, and meanwhile the iron starts to saturate as more of its internal moments are already aligned, and the longer coil has more resistance so the current falls. Three effects pulling in different directions produce a curve that bends over. If your data looks untidy, your data is right.

Second, the circuit. A coil of 200 turns of 28-gauge wire is only a few ohms, so a fresh D cell pushes a substantial fraction of an amp through it and the whole thing is close to a short circuit. That is why the wire warms up and why the cell’s voltage sags after a minute of continuous use. Thirty-second bursts with the cell disconnected in between keep the comparison fair and keep the cell alive. This also explains why a 9-volt block is a bad choice despite the bigger number: its internal resistance is high and its capacity tiny, so it heats up and fades within a couple of minutes.

How to Explain It to Your Kid

Ages 5–8: Electricity makes magnets

Electricity running through a wire makes a magnet around it, and the more times you wrap the wire round, the more magnet you get. The best part is the switch: real magnets are always on, and this one is only a magnet while you hold the wire. Have them do the holding and the letting go themselves, several times. Then do the pencil test with them and ask which bit they think is doing the magic, the wire or the nail. Most children guess the wire, and being wrong about that out loud is better than being told.

Ages 9–12: Turns, current, and a graph

Field strength depends on how many turns there are per centimetre and on how much current flows. Have them make a table with turns in one column and clips in the other, three trials per row, and plot it. Then ask why the line bends instead of staying straight. Three candidate answers are available to them: the iron runs out of alignment to give, the longer wire has more resistance, and the battery sags. All three are true, and deciding how to test them separately is the real exercise.

Ages 13+: Permeability, saturation and a fair test

Introduce the solenoid field as proportional to turns per unit length and current, and the role of the core’s relative permeability in multiplying it. Then attack the experimental design. Current is the variable they are not controlling: have them put a multimeter in series and record current alongside clips for every turn count. Once they can see current falling as turns rise, the bending curve stops being mysterious and becomes arithmetic.

The question to ask: “If I wind 200 turns but half of them in the opposite direction, how many paperclips do I get?”

Why Teaching This Early Pays Off

Electromagnetism is the link between two things children experience as separate: electricity, which comes out of batteries, and magnetism, which lives in fridge magnets. Welding those together early makes motors, speakers, generators, hard drives, induction hobs and maglev trains variations on one idea rather than six separate mysteries.

The control experiment in step 5 is worth as much as the physics. Swapping the nail for a pencil while keeping everything else identical is a genuinely fair test, and fair testing is one of the named science and engineering practices in the Framework for K-12 Science Education (National Research Council, 2012). The prediction-before-measurement habit this article keeps insisting on is the Predict-Observe-Explain structure described by White and Gunstone, and it only works if the prediction is spoken before the lid comes off. A single afternoon will not transform anybody’s school performance. What it can do is make “change one thing at a time” a reflex rather than a rule from a worksheet.

Before You Start: What Parents Should Know

Best age	7 with an adult winding; 10 and up for the measurements and the graph
Supervision	Adult handles the nail, the connections and the timing. Children wind and count
Real hazards	Heat: the coil and cell get warm in under a minute and hot if left connected. Sharp nail point. Small paperclips are a choking hazard for children under three, so keep the pile out of reach
Don’t	Never connect a coil to a wall socket, a mains adapter, a phone charger or a car battery. A coil is a near short circuit, and a mains source will deliver enough current to start a fire within seconds. One 1.5-volt cell is the entire power supply for this experiment, and that is not a limitation to work around

When It Doesn’t Work

• Nothing happens at all. Check the ends. Enamelled wire’s varnish is invisible, and unsanded ends mean no circuit. Sand until bright, then check continuity by touching the ends to the cell and feeling for warmth after ten seconds.
• It lifts one clip and no more. Either the core is wrong or the winding is. Confirm the nail is plain steel by checking that an ordinary fridge magnet sticks to it; stainless, brass and aluminium will not work. Then check your winding for a section that reverses direction.
• It worked and then faded. The cell is sagging under a near-short load, and the coil is warm. Disconnect, wait a minute, retest. If performance does not recover, the cell is spent.
• More turns made it worse. Possible and interesting. Extra turns add resistance, which cuts current, and if your wire is thin the loss can outweigh the gain. Measure the current with a multimeter and the puzzle resolves.
• The nail stays magnetic afterwards. That is residual magnetism, stronger in hardened steel than in soft iron. It is not a fault. Tapping the nail or heating it gently disrupts the alignment, which is a small bonus experiment.

Take It Further

Turns versus current, separated: add a multimeter in series and a 1-ohm or 2-ohm power resistor you can switch in. Now you can hold turns constant and vary current, or hold current constant and vary turns. Two graphs instead of one, and the shapes differ.

Core shoot-out: wind a fixed 100 turns and swap the core, keeping everything else identical: steel nail, bolt, bundle of thin iron wires, aluminium rod, pencil, glass rod. Rank them by clips held. The bundle of thin wires often beats the solid nail, which is a result that leads straight into why transformer cores are laminated.

Where This Electromagnet Experiment for Kids Fits in a Sequence

Do magnetism before electromagnetism. A child who has already mapped a bar magnet’s field with iron filings has a picture of what the coil is producing, and our first electromagnet walkthrough is the gentler version if your child is at the younger end. Afterwards, two routes open up. Towards machines: how electric motors work uses this exact coil to produce rotation. Towards communication: building a telegraph uses the switchable part, which is the feature that made electromagnets historically important in the first place.

What to Watch For Over the Next 3 Months

• Week 4: they point out that a speaker, a doorbell or a scrapyard crane must have a coil in it.
• Month 2: they propose a fair test for something unrelated, with the phrase “keep everything else the same”.
• Month 3: they ask why some magnets can be switched off and others cannot, which is the doorway to permanent magnetism and domains.

Frequently Asked Questions

Can I use ordinary insulated hookup wire?

Yes, but you will fit far fewer turns because the plastic insulation is thick, so the magnet will be weaker. It is a reasonable fallback. What you cannot use is bare wire, because adjacent turns touch and most of the current takes a shortcut instead of going round the coil.

Why not use a 9-volt battery for a stronger magnet?

A 9-volt block looks better on paper and performs worse in practice. Its internal resistance is high and its capacity is small, so under a coil’s near-short load the voltage collapses, the battery gets hot and it is flat within minutes. A D cell delivers more current for longer.

Does the nail become a permanent magnet?

Slightly, and temporarily. Some alignment of the iron’s internal magnetic domains survives after the current stops, which is called residual magnetism. Hardened steel keeps more of it than soft iron. Tapping the nail firmly disrupts the alignment and most of the effect goes away.

Is it safe for the wire to get warm?

Warm is normal and expected for a coil on a cell. Hot is a signal to disconnect. The real rule is that nothing here is ever connected to anything other than a 1.5-volt cell, because the same coil on a mains supply would be a fire, not a magnet.

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About the author

Ricky Flores is the founder of HiWave Makers and an electrical engineer with 15+ years of experience building consumer technology at Apple, Samsung, and Texas Instruments. He writes about how kids learn to build, think, and create in a tech-saturated world. Read more at hiwavemakers.com.

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Sources

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2. Nave, R. “Magnetic Field of a Current.” HyperPhysics, Georgia State University. http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magcur.html
3. National Institute of Standards and Technology. “The Ampere.” SI Redefinition. https://www.nist.gov/si-redefinition/ampere-introduction
4. National Research Council. (2012). A Framework for K-12 Science Education. National Academies Press. https://doi.org/10.17226/13165
5. White, R. T., & Gunstone, R. F. (1992). Probing Understanding. Falmer Press.
6. Alfieri, L., Brooks, P. J., Aldrich, N. J., & Tenenbaum, H. R. (2011). “Does discovery-based instruction enhance learning?” Journal of Educational Psychology, 103(1), 1–18. https://doi.org/10.1037/a0021017