Fun and easy lava lamp science experiment for kids

The preschool children at Guardian Childcare & Education Tempe love to learn about the wonderful world of science through easy experiments. Here, the team shares one of our favourite experiments, the DIY Lava Lamp, which can be replicated at home!

The best thing about this experiment is that it requires relatively few materials (most of which you can find around the house) and encourage a sense of curiosity in your child. Take the time to ask them questions throughout, asking their opinion and what they think will happen next.

Instructions

1. Fill the bottle up about 1/4 with water.
2. Pour the vegetable oil in the bottle until it is almost full. You may want to use a measuring cup with a spout or a funnel to avoid spilling. Once filled, wait a couple of minutes for the oil and water to separate.
3. Add a few drops of your favourite food colouring. Watch as the food colouring sinks through the oil.
4. Break your fizzy tablet in half and drop part of it into the bottle. Get ready, here come the bubbly blobs.
5. If you have one handy, grab a torch, turn off the lights and drop in another half tablet. Get your child to shine the torch through the lava lamp while the blobs are bubbling.

How it works
The oil floats on top of the water because it is less dense, or lighter, than water. The food colouring has the same density as the water so it sinks through the oil and mixes with the water. When you add the tablet it sinks to the bottom then starts to dissolve. As it dissolves it makes gas, also known as carbon dioxide. Gas, or air, is lighter than water so it floats to the top. The air bubbles bring some coloured water with them to the top. When the air comes out of the coloured water blob, the water gets heavy again and sinks. It does this over and over again until the tablet is completely dissolved.