British inventor Edward Craven Walker invented the lava lamp in the 1960s. In 1963 he saw something at a pub in England that inspired him to create the “Astro Lamp” (The name was changed to lava lamp or lava light later). Inside an airtight tube of glass, a “concoction” of wax and oil is inside water. The wax and/or water are sometimes colored to add to the visual appeal.

A lightbulb at the base of the tube heats the wax. Since we know that heating something causes the particles expand, we inferred that the wax would become less dense. Eventually, it become less dense than water and rises to the top of the tube, where it cools back down and sinks. Why does it sink? If you thought that when cooling the wax, down, the particles become closer together and get denser, you were correct!

Based on that information, we decided that our own lava lamp should be built by suspending wax in a glass jar and heating it up with a light underneath. The light should serve as an adequate heat source to make the wax expand. That being done, we proceeded to create a hypothesis and conduct our experiment.