Homemade lava lamp

Build a homemade lava lamp and use a surprising property of citrus fruits to explore the science of floating and sinking.

red curly haired young girl smiles to the camera, next to her is a glass filled with oil and some red liquid
Viola, 5, with her homemade lava lamp, Image credit: The Royal Institution

Aims

Make a home-made lava lamp.

ExpeRiment with objects of different shapes and sizes. See what makes a difference to whether something sinks or floats in water.

Learn how an object’s density affects if something is likely to sink or float.

About this activity

Build a home-made lava lamp and use a surprising property of citrus fruits to explore the science of floating and sinking

Olympia Brown does science at home with her daughter investigating density.They discover that an orange sinks when it is peeled and try objects from around the home to see if they float or sink. In this fun children's activity, prediction, and asking questions, help to explore the science.

The Royal Institution is closed 19 March

The Ri is closed this week on Tuesday 19 March.