Video narration
When litmus paper changes color, what is that color actually telling you? Think of a traffic light: its colors signal categories. Litmus is a dye that gives you a clue about a liquid, not decoration. That shift is useful information, giving you a first clue. In an acidic liquid, litmus turns red; in a basic liquid, it turns blue. Those colors tell you what kind of solution you're testing. Neutral is different: litmus solution is purple, while litmus paper may simply show no change in a neutral liquid. The paper doesn't have to turn purple. Here's the limit: the color tells you whether a solution is acidic or basic, but it does not tell you how strong it is. So what does litmus tell you? Red means acid, blue means base, and purple is neutral litmus solution. It signals the type, not the strength.