Magnetic Slime

Welcome to Science Sunday Season 3! We are so excited to share another round of science experiments with you. We are kicking off season 3 with Magnetic Slime! Pretty sure you have already made slime, who hasn’t? I am also pretty sure you have already played with magnets. Today we combine these two worlds into one awesome science experiment.

What you will need:

8 oz of white school glue
1 teaspoon of Borax
Large mixing bowl
Plastic Cup
Measuring Cups and Spoons
Iron Fillings
Neodymium Magnet
Water
Food Coloring (optional)
Spoon/Spatula

What to do:

First, pour 8 oz of glue into your large mixing bowl.
Add water to your glue bottle and shake and pour it into the large mixing bowl.
Stir your glue and water together
Add a generous amount of iron filings
Mix your iron filings and glue mixture together
Add a teaspoon of Borax to a 1/2 cup of Hot water
Mix it together and add food coloring (optional) Be sure the Borax dissolves completely.
Mix Borax mixture to glue mixture
Stir and then knead with clean hands.
Next, lay your slime flat, and use your Neodymium Magnet to pull up the slime!

Tip!

You can save your Magnetic Slime in an airtight container in the fridge.

How does it work?

The iron filings cause this slime to be magnetic. Iron is one of three elements (cobalt, iron, and nickel) that are magnetic at room temperature.

Steel Chain

The solution of school glue with borax and water produces slime which flows slowly. The glue is actually made of a polymer material. A polymer is simply a long chain of identical, repeating molecules. You can use the image of tiny steel chains to understand why this polymer behaves the way it does.

Each link in a chain is a molecule in the polymer and one link is identical to another. When the chains are in a pile and you reach in to grab one, that’s what you get. If you dump them on the floor, they’re not connected to each other so they spread out everywhere like water. The strands flow over each other like the liquid glue in the bowl. Something caused a change, however.

Understanding the Change

If you toss a trillion tiny, round magnets into the pile of steel chains, when you reach in to grab a strand, you will grab hundreds instead. This is because the magnets have linked the strands together. If the molecules stick together at a few places along the strand, then the strands are connected to each other and the substance behaves more like a solid. Sodium tetraborate is the chemical in Borax that hooked the polymers in the glue together to form the gooey slime. This process is called cross-linking.

The magnet is super strong. What prevents the iron filings from leaving the slime and attaching the magnet?

The slime holds onto the iron filings by adhesion. Adhesion is a force that holds molecules of different substances together. In addition to adhesion, the slime polymer is bonded by cohesion. That’s a force that holds molecules of the same substance together. It’s the combination of magnetism pulling one way and adhesion and cohesion pulling the other. Isn’t that neat?