Clock is a kind of timer commonly used in life, and people record time through it. There are four generations of clocks and watches recorded in the history of China: sundial, hourglass, mechanical clock and quartz clock. A clock is also called a clock.

The understanding of clocks can be divided into two parts, one is the understanding of the clock face, and the other is the reading of time. Knowing that the clock face is the foundation and seeing time is the ability requirement.

Clock face knowledge is a content of primary school mathematics learning, which is divided into two learning periods. The first study period is grade one, when do you know exactly when to know 30 minutes, the second study period is grade two, and the third study period is the second study period.

These times are all read by the clock face. Let's get to know two different clock faces together. One is an electronic watch, which directly displays time, minutes or even seconds, such as 6: 30: 25, that is, 6:30:25. The other is a mechanical clock face, which means that there is a scale.

Such a clock face must know the relevant knowledge of the clock face: first, the clock includes the pendulum, the hour hand and the minute hand; Second, the pendulum is equivalent to the second hand of the current watch, swinging for one second at a time; Third, the minute hand moves for one minute every time; Finally, every number that the hour hand moves is one hour. The second hand is the thinnest and longest, the minute hand is long but not very thin, and the hour hand is thick and short. The second hand goes fastest and the hour hand goes slowest.

For example, there are 12 large squares and 60 small squares on the clock face. The thick hand on the clock face is an hour hand, the minute hand is a minute hand and the longest hand is a second hand. And the second hand walks a small square 1 second, the minute is 1 minute, and the second hand walks a small square, so 60 seconds is equal to 1 minute, and the minute hand walks.

The main way to read time is to look at the value and scale pointed by the pointer. It is difficult for a general mechanical clock to read a few seconds, which are all hours and minutes.

How to read the whole hour: the minute hand points to 12, and the hour hand points to the number, that is, the hour. For example, at 6 o'clock, the minute hand on the clock face points to the number 12, and the hour hand points to 6.

How to read half an hour (that is, half an hour): at this time, the minute points to 6, and the hour hand points to the middle of the two numbers. At this time, the time is half an hour of the smaller one between two numbers. For example, at 6: 30, the minute points to 6 and the hour hand points between 6 and 7.

How to look at time and minutes: first look at which scale the minutes point to, that is, a few minutes, then look at how many minutes the hour hand points to, and the smaller number is what time. If the hour hand on the clock face points between 12 and 1 1, and the minute hand points to 18 cell, the current time is 18 minutes 1 1.

There are two formats for recording time: one is the spreadsheet format, such as 6:30:25, which is pronounced as 6: 30: 25; One is the common timing method, such as 6: 30: 25.