Chemistry with Cabbages

The year 6 children made an indicator out of cabbage juice today and then tested the pH of some household chemicals like: vinegar, soap, sugar, lemon juice and surface cleaner.  Purple plants (like cabbage) turn red in acids and green in alkalis therefore they are good to use as an indicator. 

They moved their experiment on by conducting a neutralisation test; acid is the opposite of alkali so mixing the two makes neutral.  

After that the children had fun with sodium bicarbonate, acid and a rubber glove!  Sodium bicarbonate is an alkali, so it neutralises acid.  The reaction produces carbon dioxide gas which is why it fizzes and bubbles.