Science in Sweatpants: Magnetic Slime

Let’s make some magnetic slime! This experiment is really fun and simple but definitely requires adult supervision.

Typically, Science in Sweatpants features ingredients that are easily found at home. This demonstration is a little different, featuring things you might not have on-hand but are easily found online, at craft stores, or home improvement stores.

Here’s what we need:

  • 1/8 tsp. Borax powder
  • 1/4 cup white glue
  • 1/2 cup warm water
  • 3 tbsp. black iron oxide powder (found online)
  • Neodymium magnets (found at local craft store or home improvement store)
  • A bowl and a cup for mixing
  • Popsicle sticks or gloves for mixing
  • Optional: An apron or an old shirt, just in case you splatter any of the substance while mixing

Safety first:

No part of this slime should be ingested. Neodymium magnets are rare earth magnets that are VERY strong. If you are doing this experiment with a child that tends to put things in their mouths or swallow things, this might not be a good experiment. If swallowed, neodymium magnets can be dangerous or deadly. Also, make sure you’re don’t inhale any of the iron oxide powder while you’re mixing everything together.

RELATED: Science in Sweatpants: Baking soda and vinegar

Let’s get started!

In a glass, mix 1/8 tsp. of Borax powder with ¼ cup warm water. Set aside.

In a bowl, mix your glue, the remaining warm water (1/4 cup), and the iron oxide powder. You can use the popsicle sticks or the gloves to mix the solution. With bare hands, you may notice some staining on your hands but this should come off with soap and water.

Once mixed, slowly add the Borax solution. Notice the mixture begins to take on a slimy consistency. If you don’t get all the liquid in the bowl incorporated, that’s okay.

If your slime is rigid or begins breaking, add more water or soak it in water for a bit. I experienced this and let it sit in a cup of water for about 10 minutes. It did the trick!

After the slime is made, it shouldn’t stain your hands anymore.

With your slime in one hand, slowly bring the magnet over to it. Notice how the slime tries to swallow the magnet!

With a little practice, you can eventually make your slime dance!


The Science Behind It:

Glue is what’s known as a PVA (polyvinyl acetate), which is a polymer. A polymer is basically a chain of repeating molecules that are connected like a strand of pearls. On their own, these strands will slide past each other without connecting.

When you add the Borax solution, the sodium tetraborate molecules act as a bridge between the molecule chains in the glue. These bridges can break and reform, helping to give slime its slimy texture.


The iron oxide powder makes the slime magnetic but it won’t really respond to a regular kitchen magnet. We need something much stronger, like a neodymium magnet.

By placing the magnet near the slime, you can see the magnet attraction as the slime crawls toward the magnet or the slime swallows it up completely!