Science at home: Lemon volcano

Introducing children to the logic and magic of science through hands-on experiments is an effective way of helping them understand scientific concepts. Here’s a simple experiment/activity you can do at home to help children understand the chemistry behind reactions to different types of acids.

Lemon suds eruption

Materials

1. Two small containers (for eruptions)
2. Food colours (to make eruptions look interesting)
3. Large plastic tub (to place the erupting containers)
4. 2 tbsp baking soda
5. 2 tbsp citric acid (lemon juice can be added instead but eruptions won’t be very dramatic)
6. ¼ cup clear liquid hand soap
7. ¾ cup warm waterProcedure

• Place the containers in the tub, away from each other.
• Pour in clear liquid hand soap till quarter of each container is filled.
• Fill the containers with warm water and mix with a teaspoon. You will get a sudsy liquid. If you want the eruptions to look interesting, add a few drops of food colour and mix well.
• Add baking soda into each container and mix well.
• Next, scoop in citric acid and mix. The mix will immediately create light and fluffy colourful sudsy eruptions. These eruptions will last for a long time.
• Try mixing several food colours and watch the results.
• If you leave out the food colours, then you will get a homemade cleaning agent. If you add lemon juice instead of citric acid, then it will become a ‘natural’ homemade cleaning acid!

This experiment teaches children about acid-base reaction. Baking soda is a base which, when mixed with citric acid or acidic lemon, releases carbon dioxide. When this bubbly gas mixes with hand soap, you get foam eruptions. The foam produced is cold. Therefore the acid-base reaction is an endothermic reaction wherein heat is absorbed and cold released. Carbon dioxide is produced, causing the bubbly reaction, just as it does when a bottle of soda is shaken and opened.

K.P. Malini