pH Indicators
pH Indicators is a group of substances that change color to show whether a liquid is an acid or a base.
Think of it this way
Red cabbage juice works like a mood ring for liquids. Pour it into lemon juice and it turns bright pink. Pour it into soapy water and it goes green. The color tells you whether a liquid is acidic, basic, or somewhere in between — all without tasting or touching it.
Explaining ph indicators by grade level
Red cabbage juice is a natural color-changer. Pour some into vinegar and it turns pink. Pour some into soapy water and it turns green. The juice changes color because those liquids are different. Pink means sour like vinegar. Green means slippery like soap. The color tells you something about the liquid you cannot see by looking at it.