This year we made very cool lava lamps with our teacher Mrs O Grady. We brought in clean glass jars and bottles. Then we put some water into the jars. Next we poured in some oil. Then we put in some of our favourite food colouring colours.
Mary and Mrs O’ Grady put in a bit of an Alka-Seltzer into our jars or bottles. It was very cool to see the lava lamp working.
This is the science behind it:
Oil and water do not mix. If you try to shake up the bottle, the oil breaks up into small little drops, but the oil does not mix with the water. When you pour the water into the bottle with the oil, the water sinks to the bottom and the oil floats to the top. Oil floats on the surface because water is heavier than oil. Water is more dense than the oil. The Alka-Seltzer tablet reacts with the water to make carbon dioxide gas. These bubbles attach themselves to the coloured water and cause them to float to the surface. When the bubbles pop, the colour sinks back to the bottom of the bottle.
See our pictures below.