detector

Everyday

A detector is a machine or device that notices or finds something, such as smoke, metal or movement. tree →

In the lessons

In safety lessons, smoke detectors (smoke alarms) warn us of fire; test them regularly. In science, detectors measure things like light or heat. In everyday life: metal detectors at airports, carbon monoxide detectors at home. Phrases: «smoke detector», «metal detector», «motion detector», «lie detector».

Examples

• The smoke detector beeped when the toast burned. tree →
• We found an old coin with a metal detector. tree →
• Every home should have a working smoke detector. tree →
• The motion detector switches on the garden light. tree →
• At the airport we walked through a metal detector. tree →
• Change the battery when the detector starts chirping. tree →
• A carbon monoxide detector can save lives. tree →

Note

From the verb «detect» (to notice or discover). Safety: a beeping or chirping detector means smoke or a low battery — tell an adult, never take out the battery to stop the noise. Countable: «a detector», «detectors».