Magnetic Levitation with Pyrolytic Graphite
Materials: ★★★ Requires materials not commonly found in school laboratories
Difficulty: ★★★ Requires a more experienced teacher
Safety: ★★☆ Some safety precautions required to perform safely
Categories: Magnetism
Alternative titles: Diamagnetism of Pyrolytic Graphite
Summary
Pyrolytic graphite is a strongly diamagnetic material that can levitate above neodymium magnets. It also conducts heat efficiently, allowing it to melt through ice easily by transferring heat from your hand.
Procedure
- Place several small neodymium magnets (e.g., 1×1 cm) side by side to create a magnetic base.
- Gently place a thin piece of pyrolytic graphite on top of the magnets. Observe as it levitates slightly above them due to diamagnetism.
- Push the graphite lightly with a wooden stick. Notice that it resists being forced into the magnetic field, maintaining its hovering position.
- For the heat conduction demonstration, hold the piece of pyrolytic graphite in your hand and press it against an ice cube.
- Observe that the graphite cuts through the ice easily, as it rapidly conducts heat from your hand into the ice.
- Compare this with an iron sheet pressed against ice to see how much slower it melts.
Links
Diamagnetic Levitation with Pyrolytic Graphite - $20 How-To - Kevin Patterson:
Levitate a Piece of Graphite on Magnets - $10 Project - Forrest Trenaman:
📄 Pyrolytic graphite - MEL Science: https://melscience.com/US-en/articles/pyrolytic-graphite/?srsltid=AfmBOooxjIRyp9DlevmnfBUOo2WYaT3bI0Q9U4PPwqvpfUJvaGbEBZhX
Variations
- Arrange magnets in different orientations to see how the levitation stability changes.
- Try different thicknesses of pyrolytic graphite to compare levitation height and stability.
- Use a thermal camera to visualize heat transfer when the graphite melts ice.
Safety Precautions
- Handle neodymium magnets carefully; they are strong and can pinch fingers or shatter if snapped together.
- Keep magnets away from electronics, magnetic storage media, and medical implants.
- Do not attempt to ingest or inhale graphite flakes.
- Avoid dropping magnets on hard surfaces, as they can chip or break.
- Wash hands after handling graphite.
Questions to Consider
- Why does pyrolytic graphite levitate above magnets while most materials do not? (It is strongly diamagnetic, creating a repelling magnetic field.)
- How does this compare to superconductors that also levitate? (Superconductors show perfect diamagnetism via the Meissner effect, while graphite shows weaker but noticeable diamagnetism.)
- Why does graphite melt ice so quickly compared to iron? (It is an excellent thermal conductor, transferring heat from your hand efficiently into the ice.)
- What practical applications exist for diamagnetic levitation? (Examples include magnetic levitation for frictionless bearings, stable positioning systems, and demonstrations of fundamental physics.)