DIY lava lamp experiment

Gather your friends and try a fun science experiment this weekend

Materials needed

A clear empty water bottle or flask

Vegetable oil

Water

Food colours

Antacid tablet (Eno)

Method

Fill ¾ of the bottle with vegetable oil.

Fill the rest of the bottle with water. The oil floats and the water sinks to the bottom of the jar under the oil. The water looks like little, clear blobs and travels down to the bottom of the bottle.

Add a few drops of food colour — pick any colour of your choice. The food colouring is water-based, so it will also sink and colour the water that is now at the bottom of the flask.

Break an antacid tablet into small pieces, and drop them into the flask one at a time. Watch your lava lamp erupt into activity! As the chemical reaction slows down, simply add more antacid tablets.

The science behind it:

The lava lamp works because of two scientific principles: density and polarity. Density is the measurement of how compact a substance is, because water is denser than oil, it will sink to the bottom when the two are put in the same container.

While water molecules are polar and oil molecules are non-polar, polarity prevents the oil and water from mixing together.

The movement in the lamps is created due to the antacid tablets. The antacid reacts with the water to produce carbon dioxide gas bubbles. These stick to the water droplets. The water and gas combo is less dense than the oil, so they rise to the top of the flask.

(Parental supervision recommended.)