Build an Electromagnet

Wind insulated copper wire around an iron nail, connect it to a 9V battery, and watch a plain steel spike start pulling paper clips off the table. Oersted's 1820 discovery, recreated in your kitchen with a spool of magnet wire. This experiment explores electromagnetism and Ampere's Law, the same physics behind electric motors, MRI machines, speakers, maglev trains, and every hard drive read head ever made. Students wind and test coils at 20, 40, and 60 turns to see whether lifting strength scales linearly with turns, swap in a steel nail and a wooden dowel to isolate the core's contribution from the coil's, and time how long residual magnetism lingers after the battery disconnects. Every trial produces an immediate, countable result — clips lifted and every result traces back to a clean, testable equation. This is hands-on electromagnetism that connects circuits, materials science, and engineering design in a single hour-long build.

What's Included

• Iron nail, 3–4 inch — the ferromagnetic core
• Steel nail, same size — for core material comparison
• Magnet wire, 26 AWG, ~1.5m — enamel-coated for tight, consistent coils
• 9V battery — for safe, repeatable connections
• 2x alligator clips
• Paper clips × 25 — test objects for measuring lift strength
• Sandpaper — for stripping enamel from wire ends
• Printed worksheet

You Provide

• Ruler or tape measure
• Scissors or wire strippers
• Stopwatch or phone timer
• Wooden dowel or pencil (for air-core comparison)

♻ Waste Disposal
Rating: Easy
Nail, wire, and paper clips are fully reusable. Unwind the coil and store it for future builds. Copper wire and steel/iron nails can go to metal recycling if discarded. The one exception is the 9V battery: don't toss it in regular trash, since it contains heavy metals. Most hardware and electronics stores take batteries back for free recycling.

Curriculum Connections

• NGSS HS-PS2-5 / MS-PS2-3 — Evidence that fields exist between objects without contact
• NGSS HS-ETS1-2 / HS-ETS1-4 — Design optimization through systematic variable testing
• AP Physics C, Unit 11 — Ampere's Law, solenoid fields, ferromagnetism, back-EMF
• IB Physics Topic 5 / Topic 12 — Magnetic fields from currents, hysteresis at HL
• Common Core HSA-CED / HSF-LE — Testing and graphing a linear relationship (B ∝ N)