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)
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