Yesterday, our budding scientists in Years 7 & 8 made lava lamps during Science Club at lunchtime.  Mr. Cutts demonstrated how the oil stays above the coloured water because it is lighter/less dense.  Students then added a dissolving tablet which released a gas which rises to the surface.  As the gas rises, it brings with it some of the coloured water which then sinks back down to the bottom, making an effective lava lamp!

If you would like to try this at home, here are the instructions:

Materials:

• A clean plastic bottle, try to use one with smooth sides
• Water
• Vegetable Oil
• Fizzing tablets (such as Alka Seltzer or Vitamin C)
• Food Colouring and/or Glitter

Instructions:

1. Fill the bottle up about 1 quarter with water.
2. Add a few drops of your favorite food colouring and/or glitter.
3. Pour the vegetable oil in the bottle until is almost full. You may want to use a funnel. You may have to wait a couple of minutes for the oil and water to separate.
4. Break your fizzy tablet in half and drop part of it into the bottle. Get ready… here come the bubbly blobs!