stopwatch

Everyday

A watch or timer that can be started and stopped by pressing a button, to measure exactly how long something takes. tree →

In the lessons

In science lessons a stopwatch measures time in experiments (how long a ball takes to fall, a pendulum's swing). In PE it times races. In maths you read stopwatch times in minutes, seconds and hundredths of a second and work out differences; reaction time causes small errors.

Examples

• The coach timed my sprint with a stopwatch. tree →
• Start the stopwatch when the ball is dropped. tree →
• The stopwatch showed 12.45 seconds. tree →
• Ali ran in 9.8 seconds and Ben in 10.3, so Ali was 0.5 seconds faster. tree →
• Most phones have a stopwatch app. tree →
• Repeat the timing three times and find the average. tree →

Note

Plural: stopwatches (-es). Stopwatch times are often in seconds with decimals: 1:05.20 = 1 minute 5.20 seconds = 65.2 seconds. Lower time = faster in a race.