Activity/Demo Overview
This demo demonstrates superconducting phenomena in a tabletop setup by freezing a metal alloy with liquid nitrogen until it reaches a superconducting state.
This activity involves a dewar of liquid nitrogen, a metal puck made with a superconducting alloy, safety gloves and goggles, a magnetic rail, tongs, and a plastic container.
Activity/Demonstrator Notes
How to set it up:
- Put on PPE and pour liquid nitrogen from the metal dewar into the plastic container.
- Place the metal puck inside the plastic container with some tongs.
- Place the frozen puck above the magnetic rail.
What to say to the audience:
- Introduce what liquid nitrogen is. Explain some of its properties such as boiling point and how it’s made.
- As the puck is cooling, describe what superconductivity is and the basics of phase transitions.
- Ask the audience what they think will happen when you place the puck on the magnetic rail.
Additional Demos:
- The magnetic puck takes some time to freeze. Bring along some disposable safe objects such as marshmallows or flowers to freeze in the liquid nitrogen and then break to get the crowd excited about liquid nitrogen.
- Bring an empty pringles can to fill with a small amount of liquid nitrogen and then place the cap on. The pringles can should operate as a cannon and be aimed away from people.
- Bring a balloon and ask small children what they think will happen when you freeze the balloon. This keeps children engaged while the puck is cooling in liquid nitrogen.