Thursday 14th May 2020

For today’s activity we are going to make a lava lamp.

Here is the science behind it…

The oil floats on top of the water because it is less dense (lighter) than water. The food colouring is the same density (weight) 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 (carbon dioxide.) Gas or air, is less dense (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.