How to Make Ferrofluid (liquid magnet)

Published by Daniel Ozori on

how to make ferrofluid

Over the past few months now ferrofluid has suddenly become a rage, Everyone wants to know how to make ferrofluid and how it works.

I was also intrigued by it so I did the usual, studied about it, and said why not write an article about my findings.

Ferrofluid was invented in 1963 by NASA’s Steve Papell to create liquid rocket fuel that could be drawn toward a pump inlet in a weightless environment by applying a magnetic field.

steve papell making feroofluid

They’re are colloidal liquids made of nano-scale ferromagentic, or ferrimagentic particles suspend in a carrier fluid (usually an organic solvent or water).

It’s like having millions of tiny little magnets in a fluid, and these magnets respond to the magnetic fields around them.

So when a magnetic field is introduced they carry themselves and the fluid along with them.

But to avoid them sticking to each other like magnets usually do, a surfactant is added to make them repulsive to one another in the fluid.

Related: how to make hot ice

Uses of Ferrofluid

As you’d imagine a fluid like this will surely have other uses other than a special kind of rocket fuel

Ferrofluid has hundreds of other uses around us like;

  • rotary seals in computer hard drives 
  • loudspeakers to dampen vibrations
  • Mechanical engineering
  • Materials science research

How to Make Ferrofluid

Ferrofluid is really easy to make, at best it only takes a few minutes.

Some things you’re going to need to make ferrofluid are;

  • Vegetable oil
  • Shallow dish
  • Iron filings (from your local hardware store)
  • Napkins
  • A magnet

Now that you have all your materials, let’s get to making it

  • Pour a bit of vegetable oil into a shallow dish, just enough to make a thin film across the bottom.
  • Pour iron filings into the oil and mix the two until they have become a thick, sludge-like material.
  • Use a napkin to absorb any excess oil and allow the ferrofluid to become thicker. A good way to do this is to attach a magnet to the outside of the dish. This will solidify the fluid and let you dab away extra oil.
  • Attach a magnet to the dish containing the ferrofluid; the fluid will solidify and take the shape of the magnetic field it is in! Removing the magnetic field will allow the ferrofluid to flow like a liquid again.
  • When disposing of your ferrofluid, do not pour it down the drain; this could lead to clogged pipes!

It’s amazing to think you can make something that was designed for NASA right at home.

Here’s a video showing you how it should like

Safety

Ferrofluid is a major skin irritant so it’s best that when working with it, you should always be on gloves

When touched it starts to move around your finger and up your nail and if not washed off immediately it could cause rashes


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