- First you need a little test tube (or a jar might work)
- We put water in the test tube up to the 1 ml mark
- Then we added 2 drops of red food colouring
- We filled the test tube up to the 4 ml mark with oil (we remembered that oil and water don't mix...so we could see the oil staying on top of the red water)
- Finally we broke up an antacid tablet and dropped little pieces in. We could see some bubbles forming on top of the water but they didn't go up into the oil...
This was a little bit disappointing. We waited...and waited...and waited...then it was home time! Mrs Sutherland left the test tube sitting on the bench and a little while later...
|Floating bits of 'lava'!|
What is happening? The bubbles are carbon dioxide and they rise to the top, through the oil, carrying some blobs of red water with them. When the bubbles reach the top, they burst and the red water sinks down under the oil again!
Do you remember why the water sinks? Tell a friend what you think!