Well of course the excitement over the (acid) vinegar and the (alkaline) calcium gave us the perfect excuse to try out a special kind of test using something called litmus paper. It comes in two colours, pink and blue.
Blue litmus paper turns pink when you dip it into an acid.
(And even though we didn’t have any, pink litmus paper turns blue when you dip it into an alkali.)
We were going to test out some different materials to see if we could find out which of them were acids. Among them baking powder…..
Tear off a little piece of blue litmus paper and dip it into the beaker of washing powder…..
After each test, put the piece of litmus paper on your table of results.
We found that out of the things we tested, vinegar and milk were acids.
We were a bit surprised about the milk, but on reflection, it was some I had discovered lurking at the back of the staffroom fridge…..it didn’t smell too good!
Oh and the bleach. That was interesting too. It seems to have taken the colour away from the blue litmus paper. Luckily it didn’t do that to our clothes.