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Groovy Lava Lamps

Have you ever seen a lava lamp? Do you know how they work? Make your own lava lamp in a cup and learn about how different liquids interact.

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  • What happens when you mix oil and water?
  • Do you know why oil sits on top of water when you pour them into the same container?
  • How will you do this experiment? On your own, in pairs or in small teams?
  • What supplies will you need for this activity?
  • What do you think will happen when you add Alka-Seltzer to your cup?


  • Fill up your cup most of the way with vegetable oil, then fill the rest of the cup with water.
  • The water will sink to the bottom of the oil and look like clear blobs – this is because the water is more dense than the oil, so the oil sits on top.
  • Add a few drops of food colouring – it will sink and colour the water at the bottom of the cup.
  • Break up an Alka-Seltzer tablet into a few pieces and then drop them into the cup.
  • Your lava lamp will start moving! When the lava slows down, add more Alka-Seltzer to get it moving again. 


  • What happened when you added the Alka-Seltzer to your cup? Is this what you thought would happen?
  • What did you learn about different liquids?


Materials list is per individual, pair or small team. 

  • A clear glass or plastic cup
  • Vegetable oil
  • Water
  • Food colouring
  • Alka-Seltzer tablets

Keep it Simple

Take it Further

  • What happens if you use different ingredients, like a different kind of oil or something other than Alka-Seltzer. Try out a few different mixtures and see what changes.