Video: Watch this demo
Description: Cool a superconductor with liquid nitrogen and a small magnet floats on it due to magnet repulsion.
- Meissner effect apparatus
- Small neodymium magnet
- Small container for LN2
- Safety gloves and tongs
- (Optional) Video Camera
- Poor some LN2 into the smaller container.
- If a video camera is requested, connect it to the AV equipment.
- Poor some LN2 into the meissner effect apparatus up to the top of the Styrofoam.
- Place the magnet above the superconductor.
- Note that it will levitate. It will levitate for several minutes until the superconductor warms up.
Concept: The Meissner effect is the expulsion of a magnetic field from a superconductor during its transition to the superconducting state. When a superconductor is cooled below superconducting temperature, it prevents any magnetic flux from going through its surface. Since magnetic flux is conserved, the exterior magnetic flux increases to balance the canceling effect within the conductor. The increase in magnetic flux outside of the conductor is what makes the magnet float in this demonstration.
Use caution when working with liquid nitrogen, as it is very cold.