Science - Lava Lamps

This morning for science talent development, we made lava lamps. We needed the following:

An empty bottle

Water

Cooking Oil

Food Colouring

2 x Vitamin Tablets

You fill the bottle with 1/4 water. You then add the oil until almost the top of the bottle. You wait for the water and the oil to separate. You add 12 drops of food colouring. (Dark colours were not my favourite). You add in the two vitamin tablets and wait for the bubbles to start!

The vitamin tablets have baking soda and citric acid in them - they react with the water to start the bubbling. The oil and water will not mix, so the bubbles take the food colouring up into the oil and then they sink back down to the water. This happens until all the CO2 gas is gone.