Katzel: Inside of a lava lamp, you've got wax ... Katzel said it's mostly water. And since wax doesn't mix with water, that makes a lot of sense. But, as you can see, it's not just water.

Water will conduct electricity, so why not use it to switch on a lamp? [Manvith Subraya]’s Hydro Lamp is, among other things, a reminder not to let Big Switch dim your idea of what’s possible ...