Sound volume

Sounds get louder as they get closer

Sounds are louder when they're close to us and quieter when they're further away. All cars and lorries make sounds when they move because fuel is burnt in the engine in little, controlled explosions and the whole machine vibrates. Bigger cars and lorries often make louder, deeper sounds because they have bigger engines and there is more material in them to vibrate. Vehicles running on rechargeable electric batteries are much quieter as they aren't burning fuel in the engine.