Plan
- 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?
Do
- 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.
Review
- 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
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
- Learn a bit more about density and what floats!
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.
