Making Ferrofluids

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.

1. Pour a thin layer of vegetable oil into a shallow dish.
2. Add iron filings and mix until it becomes a thick sludge.
3. Dab away excess oil with a napkin; placing a magnet against the dish can help solidify the ferrofluid so cleanup is easier.
4. Hold a magnet near the dish: the ferrofluid will solidify into spiky patterns that trace the magnetic field.
5. Remove the magnet: the ferrofluid relaxes and flows like a liquid again.

An alternative method using toner is given in the links below.

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/

• 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.

• 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.

• 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)?