Experimenting with Magnets: Magnetic Slime

 In Magnets and Science

Magnets have lots of practical purposes in the world. They hold things together and hold things up. They are used to make tight seals on fridge and freezer doors, and power speakers in stereos and televisions. They store data in computers and are even used in MRIs to scan pictures of people’s bodies. But they are also mysterious and lots of fun.

Let’s take a look at the lighter side of magnets and put a twist on the classic fun science experiment of making slime by adding magnets.

How To Make Magnetic Slime*

The slippery fun not quite a solid, but not a liquid substance know as slime is loads of fun on its own. But let’s take it a step further and make magnetic slime.

Materials Needed To Make Magnetic Slime

For this experiment you will need:

  • Washable White School Glue
  • Liquid Starch
  • Water
  • Black Iron Oxide Powder
  • Neodymium Magnets
  • Measuring Cups, Mixing Bowl, Spoon or Craft Sticks for Stirring

Step by Step Magnetic Slime Making Instructions

  1. Measure 1/2 cup of glue and pour it into your mixing bowl.
  2. Add 1/2 cup of water to the glue and stir.
  3. Add 1/2 cup of iron oxide powder to the bowl and stir.
  4. Slowly pour in 1/2 cup of the liquid starch while stirring.
  5. Keep stirring and knead. Once the slime starts to pull away from the sides of the bowl, knead it with your hands until no longer sticky.
  6. Transfer slime to a clean dry container and allow it to set up for a few minutes. There will be liquid leftover in the mixing bowl. Your slime may still look a bit grey at this point, but it should darken.
  7. Grab your neodymium magnets and see what happens.

The Science Behind Magnetic Slime


Glue is a polymer made up of long chain molecules that repeat and able to easily slide past each other allowing glue to flow. When the protein molecules of the glue mix with the borate ions in the liquid starch they form into larger molecules through a process called cross-linking. These larger molecules are no longer able to slide past each other, resulting in a new stretchy, goo like substance we call slime.


A magnet is a material that produces a magnetic field, a strange force around it that attracts other materials that contain iron. The iron oxide powder in your slime contains iron and when you put a magnet to it, the little bits of iron in the slime are pulled towards it by its magnetic force. If you place the magnet in the slime, the iron bits will slowly creep around the magnet appearing to swallow it up. A regular magnet is not strong enough, however. For this experiment to work you do need to use a special neodymium magnet. These magnets are extremely powerful and known as rare earth magnets.


When iron encounters water, a chemical reaction occurs. The water molecules weakening the iron and produce a red flaky substance called rust. There is both water and iron in your magnet slime which will eventually react and turn your slime brown. When this happens, it will be time to throw your slime away.

Buy Magnets Online

US Magnetix offers a large variety of industrial strength magnets and has several different neodymium magnets available for purchase from our online shop. If you have any questions about what magnet you need for this experiment or any other magnetic projects you are working on, we’d be happy to help you. Give us a call at 800-330-1432 or send us a message.



*Iron Oxide Handling Warning: Iron Oxide Dust is irritating to the respiratory tract. Inhalation of fumes may cause metal fume fever, which is characterized by flu-like symptoms with metallic taste, fever, chills, cough, weakness, chest pain, muscle pain and increased white blood cell count.

May cause eye and skin irritation.

May cause severe and permanent damage to the digestive tract. May cause liver damage. Causes severe pain, nausea, vomiting, diarrhea, and shock. May cause hemorrhaging of the digestive tract.


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