Question: How to make a lava lamp

Caroline Roche answered on 16 Oct 2025:

Your traditional lava lamps are glass bottles with coloured wax held within a liquid (usually a water mix) sat on top of a heat lamp. When the lamp is turned on, it heats up the wax which causes the wax to become less dense and rise through the liquid. Once the wax gets to the top, it cools down and sinks back to the bottom. At the bottom, it heats up from the lamp again and the cycle repeats.

To get it to work the best, you have to make sure the densities of the liquid and wax will work together properly. To dense a wax and it won’t rise, too dense a liquid and the wax won’t fall when it cools.

You can make a really simple lava lamp using cooking oil, water and a fizzy tablet. The BBC have a nice video to show you how https://www.bbc.co.uk/cbbc/makes/bp-make-a-lava-lamp.