As a series of goopy platforms climb down a bolt in a mesmerizing GIF posted on Reddit, it almost looks as if Mario should hop from one to another.
But this isn't 1990's video-game graphics, it's real life. The GIF shows a demonstration of ferrofluid, a suspension of nanosize magnetic particles in oil. The magnetic particles are small and coated in a surfactant, which is a substance like soap that helps to keep the particles evenly distributed throughout the fluid, even when they're put next to a strong magnet, said Brandon Jackson, a doctoral candidate in mechanical engineering at Michigan Technological University, who has studied applications for ferrofluids.
In the GIF posted on Reddit, and in many other similar demonstrations seen on YouTube, Twitter and GIPHY, a magnet under the bolt provides the magnetic field. The liquid aligns itself with the invisible lines of the magnetic field, resulting in the spiky look. Surface tension holds the liquid together. Meanwhile, gravity pulls the liquid down the screw, resulting in the downward motion of the "platforms." [See More Fun Chemical Reaction GIFs]
This spiky, black "thing" is actually a liquid - a ferrofluid. (Image credit: Shutterstock)The shape "is a minimum-energy solution between the gravitational energy, the surface tension energy and the magnetic energy," meaning the substance chooses the route that demands the least amount of energy, Jackson told Live Science.
In some GIFs, the demonstrator holds additional magnets, which can alter the shape of the ferrofluid further, or move it around a surface like a snuffling hedgehog.
via GIPHY
Solid-rocket propellants obviated the need for the ferrofluids in space, but scientists quickly realized that ferrofluids could also be used to form seals to protect semiconductor chips during fabrication. Probably the most common industrial application today is in speakers, Jackson said. Ferrofluids are used to dampen vibrations in speaker components to prevent a distorted sound.
Jackson and his colleagues have a different use for ferrofluids in mind. They're studying ferrofluids as self-assembling thrusters on tiny satellites. Traditional propulsion systems work well on large satellites, Jackson said, but an increasing number of the satellites shot into orbit are the size of cellphones or shoe boxes. Many use electrospray thrusters, which use tiny electrified needles to spray jets of fluid in order to propel the satellite. But the spiky hedgehog shape that ferrofluids form under the influence of a magnetic field can also shoot jets of ions — a form of propulsion that requires only a magnet, not a precision-fabricated needle.
Original article on Live Science.