Bénard cells

Bénard cells are like patterns of squiggly lines that appear when we heat up a liquid, like water or honey. They look like tiny snakes or worms that squirm around on top of the liquid.

When we heat up a liquid, the molecules inside start moving around more and more. Eventually, this causes the liquid to become less dense and rise up to the surface. As it rises, it cools down a bit and becomes more dense again, so it sinks back down.

But as the liquid sinks back down, it's met by the hot liquid that's still rising up. This collision between the two liquids creates a sort of wave pattern, which can be seen as those squiggly lines we mentioned earlier.

These squiggly lines are called Bénard cells, and they're actually a way of transferring heat from one part of the liquid to another. When the hot liquid rises up and the cool liquid sinks down, they create a flow of heat that moves from the hot part of the liquid to the cool part.

Scientists are really interested in Bénard cells because they help us understand how heat is transported in liquids. They can also be used to create certain materials, like crystals or thin films, with very precise patterns.