Monday, 16 November 2009

Red Cabbage Acid Test

Monday, November 16th, 2009
Teacher had a red cabbage in school today. It looks purple rather than red, but that is what it's called. She cut up bits of the leaves and put them in a basin of hot water. The water turned blue, and a little later it turned purple. We used this water to test whether drinks were acids or not. First of all we tried 7up (yes, it was in a coke bottle!). 7up turned the blue cabbage water pink. So did lemon and vinegar, and an apple slice turned the water slightly pink. All of these things are acids. The jelly sweet we used didn't turn the water a different colour at all. When we tried bread soda the water turned a greeny blue. At the end of all the testing we mixed an acid (vinegar) with a base (bread soda) and the colour went back to the colour it was at the start (pH neutral). We loved all the colours, and we know now that we should wash our teeth after drinking (and eating) foods with acids in them.

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