Science with Santa

We had a fantastic night making lava lamps using oil, water and food colouring.  The boys and girls discovered that oil sits in top of the water as it’s less dense.  When you add an alka seltzer, it reacts with the water to make tiny bubbles of carbon dioxide gas. These bubbles attach themselves to the blobs of coloured water causing them to float to the surface. When the bubbles pop,the colour blobs sink back to the bottom of the jar. The children then made beautiful decorations for their Christmas tree.