While most rare earth magnets are made from the rock hard materials we’re familiar with, not all appear in that classic solid form. Ferrofluid is a stable colloidal suspension of superparamagnetic iron oxide nanoparticles. So, simply, it is a liquid that contains tiny magnetic particles. It’s magnetic properties comes from the magnetized iron oxide it contains. These particles are known as nanoparticles because of their small size -- the particles are actually so small that they never fully settle to the bottom of their container! Other than being really cool to look at, ferrofluids are quite special in the world of magnets. Because of their size, the particles turn ferrimagnetic magnetite into a superparamagnetic material -- meaning they don’t stay magnetized when removed from a magnetic field.

How Ferrofluids Work

Though these tiny magnets would normally run into each other and stick, due to increased surface area in the liquid, this is negated and doesn't allow the magnetite to bunch up and lose its innate properties. Once the surfactant is bonded to the nanoparticle, it is considered a ligand. The ligand also has an attraction to the carrier fluid and kind of pulls the carrier fluid with the nanoparticles as they feel the magnetic force act upon them.

How Ferrofluid Is Used

Ferrofluid has actually been around since the 1960's. NASA was the first to engineer it in order to experiment with manipulating fuel in space. Since then, it has worn many hats. The semiconductor industry uses it to create airtight seals around rotating shafts for low-pressure tools that process the silicon pieces that eventually form computer chips. It's also used in most computer hard drives. Through the process of thermomagnetic convection, ferrofluid is also used in some speaker systems to reduce heat. But for most magnet lovers, this liquid is awesome to look at and experiment with. Check out this great video to see ferrofluid in action!