How do lava lamps work?

Answer 1

The lava lamp uses a process called convection. As the wax heats up, it expands, creating a greater volume so its density decreases. This makes it less dense than the surrounding liquid, causing it to rise. When the wax reaches the top of the lamp, away from the heat source, it begins to cool down. This causes the wax to contract, creating a less volume increasing its density. The wax then becomes more dense than the surrounding liquid, causing it to sink, and the cycle starts over again.
The lava lamp contains two substances which are a very closely guarded secret by the makers of lava lamps. Employees are required to sign confidentiality agreements when they are hired. So it is unknown what the two substances are exactly. One is a thick oily substance the other is a waxy type substance. A light bulb underneath the liquid part of the lamp lights the lamp and also creates just enough heat to expand the molecules in the waxy substance making it lighter than the oily substance therefore it rises in the lamp. As the waxy substance rises and travel away from the heat source, it becomes cooler and more dense which makes it then fall back to the bottom of the lamp where it then repeats the this process over and over and over.

The light at the bottom of the lamp gradually heats up the material at the bottom, which therefore expands (slightly) and thus becomes less dense, causing it to slowly float upwards; when it is farther from the light is will slowly cool off, contract, and sink. So the process repeats endlessly, until the light burns out.

Answer 2

they don't