Chemical Energy
Making a Lava Lamp
Equipment: Plastic bottle, oil, water, food dye, effervescent tablets
Chemical energy is energy that is released during chemical reactions.
Batteries, food, and fuel such as coal, oil and petrol are all stores of
chemical energy, which can be released under certain conditions
(e.g. connecting batteries into a circuit, chewing food, burning fuels…)
Alka-Seltzer tablets contain two chemicals (citric acid and bread soda)
which form a chemical reaction when they meet water, producing
carbon dioxide gas as one of its products. Alka-Seltzer does not
dissolve in oil.
Oil and water do not mix. Oil is lighter than water so it sits on top of water
when it is added. The food colouring does not dissolve in oil and is heavier
than oil, so it falls through the oil down to the water and mixes with the
water.
When you drop the Alka-Seltzer tablet into the oil and water, it falls
down through the oil (it does not dissolve in the oil) to the bottom,
where it reacts with the water (a chemical reaction) to produce carbon
dioxide gas. These bubbles of gas rise through the oil to the top of the
bottle because they are light, taking some coloured water with them.
The bubbles of gas burst when they reach the top, the gas escapes
