How to Make Magnetic Slime

Put a twist on the classic slime science project by making magnetic slime. This is slime that reacts to a strong magnetic field, like a ferrofluid, but it's easier to control. It's easy to make, too. Here is what you do:

Magnetic Slime Materials 

• white school glue (e.g., Elmer's glue)
• liquid starch
• iron oxide powder 
• rare earth magnets

Ordinary magnets are not strong enough to have much of an effect on magnetic slime. Try a stack of neodymium magnets for the best effect. Liquid starch is sold with laundry aids. Iron oxide is sold with scientific supplies and is available online. Magnetic iron oxide powder is also called powdered magnetite.

Make Magnetic Slime

You could simply mix the ingredients together at once, but once the slime polymerizes, it difficult to get the iron oxide to mix in evenly. The project works better if you mix the iron oxide powder with either the liquid starch or glue first.

1. Stir 2 tablespoons of iron oxide powder into 1/4 cup of liquid starch. Continue stirring until the mixture is smooth.
2. Add 1/4 cup of glue. You can mix the slime together with your hands or you can wear disposable gloves if you don't want to get any black iron oxide dust on your hands.
3. You can play with magnetic slime just like you would with regular slime, plus it is attracted to magnets and is viscous enough to blow bubbles

Safety and Clean Up

• If you wrap the magnets with plastic wrap, you can keep the slime from sticking to them.
• Clean up slime using warm, soapy water.
• Do not eat the slime, since too much iron is not good for you.
• Do not eat magnets. There is a recommended age listed on magnets for this reason.
• This project is not suitable for young children since they might eat slime or magnets.

Ferrofluid is more liquid than magnetic slime, so it forms better-defined shapes when exposed to a magnetic field, while the silly putty is stiffer than the slime and can crawl slowly toward a magnet. All of these projects work best with rare earth magnets rather than iron magnets. For a strong magnetic field, use an electromagnet, which can be made by running an electric current through a coil of wire.