Lava Lamp

Materials: jar or bottle, effervescent tablets, oil, water, food colouring.

Instructions: Find a large jar or bottle. Pour water (at least 300 ml) and oil (also around 300-400 ml or more). Put some drops of food colouring (any colour will do). We chose green because the children voted for it 🙂

After the food colouring gets to the water, put some Vitamin C tablets (or other effervescent tablets) inside. Observe the gas released through the oil.

Tips:

• Pour more oil for visible effects
• Get a flashlight and put it under the jar
• Use blue or red food colouring, because then you can also teach the kids about mixing colours – the blue/red bubbles will go through yellow oil and look green/orange. 

Where’s the science?

• Water and oil have different densities and that’s why they do not mix – the oil is less dense
• Effervescent tablets release gas (cover the jar opening with your hand and see what happens)