Chemistry of Everyday Life: fun facts and quiz

pH shows how acidic or basic a liquid is, from 0 to 14. Below 7 is acidic, like lemon juice; 7 is neutral, like pure water; above 7 is basic, like soap.

Key fact
Each step on the pH scale is a tenfold change.

Cooking is chemistry. Browning toast or searing a steak is the Maillard reaction: sugars and proteins react in the heat, making new flavours and colours.

Key fact
Baking soda makes cakes rise by releasing carbon dioxide gas.

Soap molecules have a water-loving head and an oil-loving tail. The tails grab grease, and water rinses the whole bundle away.

Key fact
Soap can break apart the fatty outer layer of many viruses.

Rust forms when iron reacts with oxygen and water. A similar kind of reaction, oxidation, turns a cut apple brown.

Key fact
Stainless steel resists rust thanks to the chromium in it.

When an acid meets a base, they neutralise each other, making water and a salt. Antacid tablets use a base to calm excess stomach acid.

Key fact
Vinegar and baking soda fizz because they make carbon dioxide.

Some reactions give out heat, like burning wood or hand warmers. Others take heat in, like the instant cold packs used for sports injuries.

Key fact
Reactions that release heat are called exothermic.

Plastics are polymers: very long chains of small molecules repeated thousands of times. Most plastics are made from oil or gas.

Key fact
Many plastics take hundreds of years to break down.