the pH scale is used to show how acidic or basic a substance is... you usually use red or blue litmus paper, and then using the label that comes with the paper, figure out how acidic or basic it is...
A pH level of 7 is considered to be neutral. Anything higher than 7 is considered to be a base and anything lower than 7 is an acidAnything higher than 7 is Alkaline Lowere is Acidic.