Candles can be used to time. Candles can burn stably, so they can be timed, which is the candle timing method. The method of measuring time by human beings has been constantly upgrading. In ancient times, when there was sunshine, people could tell time by the projection of the sundial. This method needs sunshine. The ancients invented many methods of timing without sunlight. Water or sand can flow steadily from one container to another, so it is also used for timing.

/kloc-in the 0/7th century, Italian scientist Galileo discovered that a pendulum with a certain length (with a heavy object at the bottom of a line or rod) is isochronous when it swings. This discovery made accurate timing possible and gave birth to the clock. Atoms and molecules vibrate at a certain tone and frequency. Atomic clocks use atoms to oscillate or oscillate at fixed periods to maintain the accuracy of time. Most of this special clock is kept in the laboratory. Now, atomic clocks are used to set universal standard time, or UTC for short. Every day, we should master the time through clocks and make reasonable arrangements for our study and life. In some competitions, everyone's performance is usually determined by timing. Now the timing also refers to the calculation based on working hours and technical proficiency.