Ferrofluids are awesome, especially when you happen to have some ridiculously strong neodymium magnets lying around.
Ferrofluids are colloids - a suspension of superparamagnetic particles in a carrier fluid. If brought into a strong magnetic field, they will form the above pattern of corrugations, an effect known as normal-field instability to physicists, and as wicked cool to everybody else.
In a completely unrelated note, bringing your fingers between two of the above-mentioned neodymium magnets hurts.
1 week ago