Concepts

Lorentz force

Overview

When conducting, a ribbon of aluminum foil "jumps" up or down in a magnetic field.

Details

Equipment

• [1] Aluminum foil ribbon
• [4] Horseshoe magnet
• [1] 6 V battery
• [1] Telegraph switch
• [3] Banana cable
• [1] Insulated alligator clip
• [1] Alligator clip
• [2] Brass weight

Classroom Assembly

1. Lay out aluminum foil ribbon with brass weights on the ends. Keep some slack in the foil.
2. Connect the battery, switch, and foil in series using the cables and clips.
3. Place the magnets in the desired configuration.

Important Notes

• Red means a north pole and blue means a south pole.
• If the demo does not work well, try adjusting the amount of slack in the foil.
• When packing up this demo, make sure not to short the battery.
• The aluminum foil becomes hot over time and the battery loses power quickly. Do not leave connected for longer than necessary.
• The aluminum foil is delicate. Handle with care.

Script

1. Ask students to predict which way the foil will shift under each magnet.
2. Close the switch. The foil should "jump" in the local magnetic field.

Additional Resources