1. Do now! Can you look carefully through the test?

2. Litmus Turns red in acid Turns blue in alkali

3. Litmus Turns red in acid Turns blue in alkali Litmus can tell us if something is an acid or an alkali, but it cannot tell us how strong the acid or alkali is

4. The pH scale The strength of an acid is measured on the pH scale pH stands for the “potential of hydrogen”

5. Universal Indicator To measure pH, we need an indicator that has a different colour for each value of pH Universal Indicator

6. It comes in the form of a paper

7. Universal Indicator It also comes in the form of a liquid

8. Measuring pH You are now going to measure the pH of various acids, alkalis and household liquids.

9. Measuring pH SubstanceColour of Universal indicator pH