DIY Micro-Galvanometer Electromagnetic Detector
A challenging, hands-on discovery and STEM project designed for curious young minds aged 10 to 14.
Materials Needed
- • Pocket magnetic compass (clear housing) (1 unit)
- • Enameled copper magnet wire (28–32 gauge) (10 meters)
- • 1.5V AA battery (and lemon battery setup from prior lab) (1 unit)
- • Fine sandpaper (1 square)
Pro Tips
- → Wind 50 neat turns of fine magnet wire directly around the compass body, leaving the needle face visible between turns.
- → Align the compass needle parallel to the coiled wire loops before applying electrical current.
- → When electric current flows through the coil, it creates an internal magnetic field that rotates the compass needle perpendicular to the wire.
Safety First
Disconnect battery test connections promptly; small wires heat up if shorted.
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Step-by-Step Instructions
Step 1
Wind 50 tight, neat turns of enameled copper wire around a standard pocket compass, leaving 20 cm of lead wire at both ends.
Step 2
Sand the protective enamel coating completely off the last 2 cm of both copper lead wire ends using fine sandpaper.
Step 3
Rotate the compass on the table until the magnetic needle points North, parallel with the loops of your wire coil.
Step 4
Touch the stripped leads across a 1.5V battery and observe the instantaneous needle deflection; reverse lead polarity to reverse the deflection direction.