Red Cabbage Lab tacid/indicate.htm has very nice cartoons to explain acids, bases, and indicators.

“Red Cabbage” changes colors according to the pH of a solution. pH is the amount of H + dissolved in water. Since water makes its own H +, pH also measures how much base is formed. Yellow, Orange, Red indicate acids of decreasing strength Green, Blue indicate bases of decreasing strength.

Lab Write-up ~pH colorRedPurpleVioletBlueBlue- green green Fill in a table listing: 1.What did you test 2.What color did you see 3.What can you conclude about the pH Procedure: The red cabbage is prepared by boiling the cabbage. The solid is discarded, and the liquid acts like an indicator. Various common substances were tested. Purpose: to learn how acids and bases affect you.