This is such a fun magnetic project. Today we are doing a magnet experiment with kids to make our own magnetic mud using ferrofluid. Making magnetic mud is a whole new level of science fun for kids – especially older kids. This magnetic mud experiment would make a terrific science fair project and is one of the best science projects on magnetism for home or the classroom.

How to make ferrofluid with iron oxide, oil, and disposable bowl and fork. Text: Science fair idea liquid magnets - Kids Activities Blog
Let’s do magnet science experiments together!

Ferrofluid Experiments for Kids

Have you ever heard of ferrofluid?  

Related: Magnetic slime & Defying Gravity  with Magnets {Cool Gravity Trick for Kids}

Today, we broke out our test tubes with the left over iron oxide powder from when we made our own tinted sunscreen and created a DIY ferrofluid concoction that we are calling magnetic mud. My kids went wild for this magnetism experiment.

What is FerroFluid?

Ferrofluids (sometimes referred as magnetic liquids) are colloidal suspensions of magnetic nanoparticles.

MAO LAB, What are Ferrofluids?

Ferrofluid is a suspension of tiny, tiny particles of metal that are responsive to magnetic fields (like iron or nickle) mixed into  an oil solution.

It looks like a liquid and acts like a liquid, but as it contains little bits of magnetic-responsive metal, it moves with  magnets.  For our solution we used powdered rust (iron oxide).

Warning About This Magnetic Science Project

Be careful with kids using ferrofluid:

  1. Your kids should not eat the iron.
  2. As it is in powder form it might be able to be absorbed into the bloodstream if ingested and iron overdoses in kids can be very dangerous.  
  3. Iron oxide powder stains everything.
  4. You might want to mix it outdoors and with disposable containers.  I mixed the iron and let the kids play with the test tubes when we were finished.
DIY ferrofluid a tutorial on how to make magnetic lava tubes
See how the magnetic mud can be manipulated through a test tube with a magnet!

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Make Ferrofluid (aka magnetic mud)

This is a great way for kids to have fun learning about metals, suspensions, magnetic qualities – all with this Iron Mud or magnetic mud science activity.

Supplies Needed for Experiment on Magnetism

Instructions to Make DIY Ferrofluid (aka magnetic mud)

Step 1

Mix the iron oxide powder into 1/4 cup of oil.  

Step 2

We mixed it a tablespoon at a time and stirred until it was completely mixed in, smooth, no clumps, but also a bit thick.  

Step 3

Drop the mud into a test tube filled with water.  Cork it and then use the magnet to move the iron “mud” around the tube.

Step 4

Use multiple magnets to see if you can get the magnetic mud blob to move in multiple directions at the same time.

Magnetic Mud Science Experiment

DIY ferrofluid a tutorial on how to make magnetic lava tubes

Make science exciting with this ferrofluid. Ferrofluid acts like a liquid, but can be manipulated with a magnet. So cool!

Prep Time 10 minutes
Active Time 20 minutes
Total Time 30 minutes
Difficulty easy
Estimated Cost $15-$20

Materials

  • Vegetable Oil
  • Iron Oxide Powder
  • Disposable spoon and bowl
  • Test Tube

Tools

  • Face mask and/or gloves - you don't want to inhale the powdered metal or stain your hands.

Instructions

  1. Mix the iron oxide powder into 1/4 cup of oil. We mixed it a tablespoon at a time and stirred until it was completely mixed in, smooth, no clumps, but also a bit thick.  
  2. Drop the mud into a test tube filled with water.
  3.  Cork it and then use the magnet to move the iron "mud" around the tube.  
  4. Use multiple magnets to see if you can get the blog to move in multiple directions at the same time.

Notes

You will want to be careful with kids in this experiment.  Your kids should not eat the iron.  As it is in powder form it *might* be able to be absorbed into the bloodstream if ingested and iron overdoses in kids can be very dangerous.  Also, the iron oxide powder stains everything.  You might want to mix it outdoors and with disposable containers.  I mixed the iron and let the kids play with the test tubes when we were finished.

What Is The Science Behind Ferrofluids?

Ferrofluid is made of lots of tiny nanometer particles of magnetite suspended in a fluid. And while there is no magnets around the ferrofluid acts just like a liquid. The magnetite particles are easy to move freely around in the fluid it is in. When there is a magnet, the magnetite particles are temporarily magnetized. Neat, huh?

Why Does Ferrofluid Get Spiky?

If you put a strong magnet near your ferrofluid, you may see that spikes form. The spikes form because of the particles lining up along the magnetic field lines to lower their energy. Because of the surface tension though, there are limits to which the particles can line themselves up with the field.

Can Ferrofluid Go Bad?

Your ferrorfluid can dry out. But, you can rehydrate it fairly easily. But, if you leave it in a tightly sealed glass container it can last up to 10 years.

More Fun Science Experiments From Kids Activities Blog

How did your DIY ferrofluid turn out? Did your kids love making their own magnetic mud?



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