Maths

Time is when an event is happening.

There are different ways to measure units of time.  Some examples of my maths is down below

Singing a song has different tempos/speed depending on how fast or slow someones singing it. Washing your hands mostly take about 20 seconds. 

The pendulum clock is a clock that uses a pendulum, a swinging weight, as it is a timekeeping element.  

The advantage of a pendulum is that it swings back and forth at a precise time interval dependent on its length, and resists swinging at other rates.