🍋 Acids and bases: the pH scale

Unit 2 · Matter, forces & life · 9 min

pH runs from 0 to 14: below 7 is acidic (lemon juice ≈ 2), 7 is neutral (pure water), above 7 is basic (soapy water ≈ 10). Adding water to an acid moves its pH slowly towards 7.

Words in this lesson

• 酸 (suān) — acid
• 碱 (jiǎn) — base / alkali

Project: Boil red cabbage to make an indicator, then add drops to vinegar, baking-soda water and plain water and watch the colours. (With an adult.)