Ferrofluid

Ferrofluid isa liquid that is attracted to the poles of a magnet. It is a colloidal liquid made of nanoscale ferromagnetic particles suspended in a carrier fluid.

Loudspeakers

Ferrofluids are used to improve the performance of speakers and improve sound quality. In a speaker, a coil at the center of the circular magnet is used to carry the electric energy. Due to the magnetic field generated by electrical power, the coil vibrates, producing sound and heat. The electric loop is run through a Ferrofluid, controlled by the circular permanent magnets. The Ferrofluid dampens the unwanted resonances of the music and helps dissipate excess heat energy to the coil.

Mechanical engineering

Ferrofluids function like a lubricant for magnets due to their unique chemical composition. When you apply them to the surface of a neodymium magnet, the magnet can smoothly move along a surface.

Space rockets

With the onset of the space program, engineers' focus turned to the behavior of fluids in microgravity.  Advanced space missions would require spacecraft to restart their engines. It was not yet understood how liquid propellants would react to the absence of gravity.  Rocket designers had to make sure that the fuel—which might settle or disperse inside the tank—could be pumped to the combustion chamber. 

Medication

Experiments in the biomedical research area are underway to validate the applications of Ferrofluids in the field. Research is being conducted to design ferrofluids that can be used to carry medications to specific locations in the body. They could also be useful in directing drugs to certain parts of the body. It is possible to use applied magnetic fields. This could be helpful in treating cancerous cells and tumors directly with chemotherapy without wrecking other uninfected parts of the body.

Ferrofluid toys

An experiment you've never seen before. Using a glass jar, you can add salt water and ferrofluid to build your ferrofluid toy. 

Venom

If you want to look like Venom, grab the super magnet and put your hand closer to the ferrofluid.