Johanna Preethi Shama M.

The lava lamp experiment demonstrates and explains the concepts of liquid density and chemical reactions to children.

Materials
 Food colouring
 Small cup
 Vinegar
 Baking soda
 1 litre bottle or jar
 Vegetable oil
 Spoon
 Small torch or phone

Experiment
Step 1
 Put three tablespoons of baking soda in the 1 litre bottle/jar.
Step 2
 Fill 2/3 of the bottle or jar with vegetable oil without letting it mix with the baking soda.
Step 3
 In the small cup, add 3 drops of food colouring and some vinegar. (To make it more attractive, you can mix colours and add glitter)
Step 4
 Slowly add the food colouring and vinegar solution to the bottle/jar and observe what happens!
 To produce the distinctive lava lamp glow, place your phone torch below the bottle to light up the bottom.

Observations
 The density (mass/weight) of vinegar is greater than of vegetable oil; hence it sinks to the bottom of the jar, making it “heavier.”
 Chemical reactions are the second observation. The vinegar combines with baking soda to release carbon dioxide. This gas manifests as bubbles pushing the liquid to the top. When the bubbles pop, blobs of colored water fall back to the bottom of the glass.