Making Ferrofluids
Materials: ★★☆ Available in most school laboratories or specialist stores
Difficulty: ★★☆ Can be done by science teachers
Safety: ★☆☆ Minimal safety procedures required
Categories: Magnetism
Alternative titles: DIY Ferrofluid
Summary
Ferrofluids are liquids that behave like magnets when exposed to a magnetic field. By mixing iron filings with oil, you can create your own ferrofluid and watch it switch between liquid and solid-like states depending on whether a magnet is nearby.
Procedure
- Pour a thin layer of vegetable oil into a shallow dish.
- Add iron filings and mix until it becomes a thick sludge.
- Dab away excess oil with a napkin; placing a magnet against the dish can help solidify the ferrofluid so cleanup is easier.
- Hold a magnet near the dish: the ferrofluid will solidify into spiky patterns that trace the magnetic field.
- Remove the magnet: the ferrofluid relaxes and flows like a liquid again.
An alternative method using toner is given in the links below.
Links
Making ferrofluid from scratch - NileRed:
How to make Magnetic Fluid (ferro fluid) - Household Hacker:
📄 Making Ferrofluids - National Maglab: https://nationalmaglab.org/magnet-academy/try-this-at-home/making-ferrofluids/
Variations
- Try using different magnet strengths and shapes to see how the ferrofluid patterns change.
- Use different container shapes (flat, convex, concave) and compare results.
- Experiment with the ratio of filings to oil to make the fluid thinner or thicker.
Safety Precautions
- Do not pour ferrofluid down the drain; dispose of it in the trash to avoid clogs.
- Iron filings can be messy - work over newspaper or a tray.
- Magnets can pinch fingers or damage electronics; handle with care.
- Wash hands thoroughly after handling iron filings and oil.
Questions to Consider
- What happens to each iron particle when exposed to a magnetic field?
- Why do spiky cone-like patterns form in the ferrofluid?
- How does the strength of the magnet affect the behavior of the ferrofluid?
- Where are ferrofluids used in real-world applications (e.g., aerospace, electronics, art)?