Jump to main content

Make Magnetic Slime

20 reviews


Active Time
20-30 minutes
Total Project Time
20-30 minutes
Key Concepts
Ben Finio, PhD, Science Buddies
How to Make Magnetic Slime


What happens when you add iron filings to regular slime? You get magnetic slime! Make your own magnetic blob that will swallow up a magnet in this fun experiment.

This activity is not recommended for use as a science fair project. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you, browse our library of over 1,200 Science Fair Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.


Prep Work

Make sure you have a clean work surface, like a kitchen countertop, that can get a little messy.


Safety Notes about Neodymium Magnets:

Neodymium magnets are very strong. Adult supervision is recommended when using them. Do not let the magnets slam together. They may pinch your fingers or crack. Keep them away from small children, pets, credit cards, and pacemakers.

  1. In the mixing bowl, thoroughly mix 1/2 C water and 1/2 C glue. Optionally, add a drop of food coloring.
  2. Add 1/2 tsp baking soda and mix completely.
  3. Add 2 tbsp contact lens solution and stir vigorously until the mixture starts pulling away from the edges of the bowl.
  4. Use your hands to knead the slime for several minutes. Do not worry if the slime is sticky at first; it will thicken as you knead it. If you do not want to get your hands messy, wear disposable gloves.
  5. Sprinkle about 1 tbsp of iron filings onto your slime. Knead the iron filings into the slime until they are evenly distributed and your slime has a uniform color.
  6. Slowly bring a neodymium magnet near the slime.
    Think about:
    What happens as you bring the magnet near the slime?

    A blob of gray slime. Fingers hold a magnet near the slime, and a small arm of the slime reaches up toward the magnet.
  7. Pull your magnet out of the slime. Tip: You may find it difficult to remove bits of slime and iron filings from the magnet. Use a damp paper towel to help wipe them off.
  8. Keep trying to use your magnet to manipulate the slime.
    Think about:
    How close can you get the magnet to the slime without the slime grabbing the magnet? Can you "steer" the slime in a certain direction with the magnet?
  9. Try dropping your magnet into the slime.
    Think about:
    Watch the magnet for a few minutes. What happens?


You can store your slime in a sealed container for a short period of time. However, eventually the iron filings will rust, and your slime will turn brown and sticky. If this happens, dispose of your slime in the trash and make a new batch.

What Happened?

When you add iron filings to your slime, the slime becomes magnetic! The slime is attracted to permanent magnets and will move toward them, even jumping up to "grab" them if you get too close.

Digging Deeper

Your neodymium magnet is a permanent magnet. It is always surrounded by an invisible magnetic field that pushes and pulls on any other magnets nearby.

The iron filings you added to your slime are ferromagnetic. They are not permanent magnets, but they can be temporarily magnetized by a nearby magnetic field, like the one from your neodymium magnet.

When you bring the neodymium magnet near the slime, the iron filings are attracted to the magnet. However, the slime is very viscous, so it moves slowly at first. The magnetic field gets much stronger very close to the neodymium magnet, so when you get too close, the slime will suddenly jump up and grab the magnet.

If you let go of the magnet, the slime will eventually "swallow" the magnet as the iron filings slowly wrap around it.

icon scientific method

Ask an Expert

Curious about the science? Post your question for our scientists.

For Further Exploration

  • Try using your phone to film a slow-motion video of the slime grabbing onto the magnet, or a time-lapse video of the slime slowly swallowing the magnet.

Project Ideas

Science Fair Project Idea
Have you ever wondered how fun toys like Silly Putty®, Gak™, and Slime™ are made? These products are so much fun because of the properties of polymers, which make them delightfully bouncy, stretchy, sticky, moldable, breakable, hard, soft, and just plain fun! In this science project you can be the developer of your own slime product by changing the amount of a key ingredient. By observing the physical properties of your results, you can choose the best recipe for your new… Read more


STEM Activity
24 reviews
It's gooey. It's sticky. It's slime! Learn to make your own homemade slime with this quick and easy recipe. Read more


Career Profile
Chemical engineers solve the problems that affect our everyday lives by applying the principles of chemistry. If you enjoy working in a chemistry laboratory and are interested in developing useful products for people, then a career as a chemical engineer might be in your future. Read more
Career Profile
What makes it possible to create high-technology objects like computers and sports gear? It's the materials inside those products. Materials scientists and engineers develop materials, like metals, ceramics, polymers, and composites, that other engineers need for their designs. Materials scientists and engineers think atomically (meaning they understand things at the nanoscale level), but they design microscopically (at the level of a microscope), and their materials are used macroscopically… Read more
Free science fair projects.