Yr 5's Lava Lamp Creations

In Science, Year 5 created lava lamps by mixing oil with water, food colouring and adding an effervescent tablet.

We noticed that the oil floated on top of the water because it is less dense and lighter than water. The two liquids separated.

The food colouring has the same density as the water so it sunk through the oil and mixed with the water, causing a physical change.

The tablet sunk to the bottom and started to dissolve, creating bubbles and forming a gas.

This was a chemical change. As air is lighter than water, the air bubbles floated to the top.