Science question: How do magnets interact with a semi-liquid state of metal?
Supplies needed:
• Face mask
• ¼ cup (60ml) vegetable oil
• Disposable bowl
• 3 tablespoons (45g) iron oxide (rust) powder
• Disposable spoon
• Clear test tube or tall plastic bottle with lid
• Water
• Glue
• Large magnet
The Experiment:
First put on the face mask. Pour the oil into the bowl and add the iron oxide powder – one tablespoon at a time. Stir the powder with the spoon until it is smooth with no clumps. It should have a thick consistency – similar to mud. Once the iron is mixed into the oil, you can remove the face mask. Fill the test tube or bottle with water. Add the iron-oil mixture to the water, one teaspoon at a time. Because oil and water do not mix, the iron fluid will remain separated from the water. If possible, glue the lid shut to keep the ferrofluid inside. Use the large magnet on the edge of the test tube or bottle to draw the magnetic mud around the jar.
The Outcome:
The magnet will attract and move the ferrofluid.
Why it worked:
Iron responds to magnets, and we made ferrofluid from particles of rust. Ferrofluid looks and acts like a liquid, but because it contains little bits of magnetic-responsive metal, it responds to magnets.
Variation:
Try mixing sugar into your water first to make it denser before dropping your ferrofuid into the tube. Are you able to get your globs of ferrofluid suspended in the water without the help of a magnet?
Source: The 101 Coolest Simple Science Experiments by Rachel Miller, Holly Homer & Jamie Harrington.