Let’s do some magical science that makes bubbles ‘POP’ in your hands. This mini-experiment uses our ‘Terrific Test Tubes’ to make small lava lamps of many colours. If you don’t have some Terrific Test Tubes with you, you can use any thin plastic containers or bottle with a lid.

Adding a torch can even make them illuminate in the dark……really cool science.


  • Water
  • Test tubes (or bottles)
  • Vegetable Oil
  • Food colouring
  • Asproclear or Alka-zeltzer



  • Water and oil can both be slip hazards if spilt on the floor. Mop up any spills immediately.
  • Food colouring can stain, wear old clothes.
  • Keep tablets away from young children. DO NOT eat any part of this experiment.
  • lava-lamp-in-a-test-tube-step-1Pour 1/3 of the size of your container with water.
  • Add food colouring to the test tubes or bottles.
  • laval lamp terrific tubes materials step2


Pour the vegetable oil so that that the test tube or bottle is almost full.

laval lamp terrific tubes materials step3

Place 1/4 of a tablet into each test tube. It will fall to the bottom of the test tube and mix with the water. Once it touches the water, it reacts and produces gas to start your lava lamp.

laval lamp terrific tubes materials step5

Check out the ‘Wacky Science’ video of this experiment and ‘What’s Going On’ series link. They are currently ‘In Production’, so check back soon…..

Wacky Science Ep

What's Going On?


This experiment looks at many science concepts: density, chemical reactions, miscibility and more.

The main concept we will talk about in this section is density.

Our lava lamp works because there is a difference in density between water, oil and carbon dioxide gas. The first stage of this lava lamp is to pour coloured water into the test tube and then pour oil slowly ontop of the water. As you may have discovered in our other experiments on density (eg Terrific Tubes Density), those that have more mass per unit area have a heavier density. Water is more dense than oil and therefore it ‘sinks’ to the bottom of the test tube.

The pictures below show you a rasberry floating in a layer of liquid with a lighter green liquid above it and a heavier red liquid below it. The second pictures shows you a glass of oil floting ontop of tap water.

fruit in drinkOil floating on water surface in a glass


In our experiment, we added the Aspro-Clear tablet which reacts in the water to produce carbon dioxide gas. The gas is lighter than water & oil and so travels upwards and escapes from the test tube top. BUT the coloured water it carries with it then falls down to the coloured water. This cycle continues and creates the lava lamp effect we love.



If you would like

– more details,

– pictures of the second half of the experiment

– information on how to investigate this further

– links to everyday examples

– management hints & teaching pointers (5P Teacher develpoment program)

 ….. then why not subscribe to one of the following


(1) Crazy science Club

Crazy Science Club slider5

(2) 5P Teacher Training course called ‘Looney Lab  Classroom Creations

Looney Lab Classroom Creations2

Or you can purchase the ‘Bright Sparkes Guide’ of this demonstration only ($2.50) which has:

    • HD pictures of experiment steps
    • Detailed explanation of science
    • Mini-challenge section (another experiment)
    • Making it a ‘Scientific Method’ experience
    • Graphing opportunities
    • REAL links and descriptions to everyday examples of concept.