gas

Everyday

1. A substance like air that has no fixed shape and spreads out to fill any space. tree →
2. A gas that burns and is used for cooking and heating: "a gas stove". tree →
3. (American, Canadian) Gasoline, the fuel for cars; British, Irish, Australian and NZ say "petrol". tree →
4. Air in the stomach. tree →
5. Gas can also be burned to make light, as in old street lamps. tree →

In the lessons

In science, matter has three main states: solid, liquid and gas; water becomes a gas (water vapour) when it boils; air is a mixture of gases (nitrogen, oxygen, carbon dioxide). In safety: natural gas smells like rotten eggs (a smell is added); if you smell gas, don't touch switches, get out and tell an adult. Phrases: gas stove, gas station, gas leak, natural gas, step on the gas (hurry).

Examples

• Air is a gas. tree →
• When water boils, it turns into a gas. tree →
• We cook on a gas stove. tree →
• If you smell gas, leave the house. tree →
• Dad filled the car with gas. tree →
• Plants take in a gas called carbon dioxide. tree →
• A balloon is filled with helium gas. tree →
• Gases spread out to fill a container. tree →
• The name glittered in gas-jets over the entrance. tree →

Note

Plural "gases". A gas has no shape or fixed size; a liquid has a fixed size but no shape; a solid has both. In the US "gas" for cars = British "petrol". Many gases are invisible.