Science glossary film: Indicator

A substance that provides a visual indication of the pH of a test material. Litmus paper gives a simple indication of whether something is acid or alkaline, while a universal indicator displays a range of colours depending on acidity. An accurate pH measurement can be made by comparing the indicator with a colour chart.

Litmus paper gives a simple indication of whether something is acid or alkaline, while a universal indicator displays a range of colours depending on acidity. An accurate pH measurement can be made by comparing the indicator with a colour chart.