Make a colourful bubbly volcano!
• Baking soda; lemon juice or a lemon cut into quarters
• Liquid dishwashing soap
• Food colouring (optional), spoon or straw
• Narrow glass or cup
1. Put a spoonful (about a teaspoon) of baking soda into a glass.
2. Stir in a squirt of dishwashing liquid.
3. Add a drop or two of food colouring, if you want coloured bubbles.
4. Squeeze lemon juice into the mixture or pour in lemon juice. Other citrus fruit juices work too, but lemon juice works the best. As you stir the juice into the baking soda and detergent, bubbles will form that will start to push up and out of the glass.
5. You can extend the reaction by adding more lemon juice and baking soda.
6. The bubbles are long-lasting. You can’t drink the mixture, but you can still use it for washing dishes.
How it Works
The sodium bicarbonate of the baking soda reacts with the citric acid in the lemon juice to form carbon dioxide gas. The gas bubbles are trapped by the dishwashing soap, forming fizzy bubbles.