5K20.35 • Eddy Currents: Acceleration Down a Ramp
Location: Cabinet 3
Concepts Conveyed:
- The following demonstration portrays Faraday’s Law where the rolling neodymium steel ball causes a change in magnetic field and this change in magnetic flux induces eddy currents in the ball and copper track.
- Additionally, Lenz’ Law is obeyed where the induced eddy currents create a magnetic field that opposes the change that created them. Both the copper track and neodymium steel ball are inducing eddy currents with the constant change in magnetic field and thus resistive forces are present as the steel ball rolls downhill.
Instructions / Notes:
- Place and release the regular ball at the top of the copper ramp. The ball should accelerate downwards and oscillate back and forth across the ramp before stopping due to friction.
- Next, place and release the neodymium magnetic ball at the top of the copper ramp. The ball should decelerate and come to a stop at the bottom of the ramp due to the copper track inducing an opposing magnetic field and therefore providing a resisting force onto the ball.
Demo Staff:
- Provide a neodymium magnetic ball and a regular ball with the demo.
Last updated on February 6, 2026