In Chemistry we’ve been looking at the polarity of different molecules. To help us with this we made lava lamps. We found that when we added oil to water they separated because oil is non-polar and water is polar.
Earlier in the lesson we had learnt that non-polar molecules and polar molecules don’t mix.
Then we added an antacid tablet to the mixture and it released gas bubbles which caused the water under the oil to rise to the top before sinking again. This created the effect of a lava lamp.