Although analog clocks are still used, although mainly for decorative purposes, it can be stated that when it comes to accuracy digital clocks are more widespread.
The twelve numerals and the large tick marks written on the clock above represent the hours, 1-12. Though many of us may be used to reading a digital clock, it can be useful to be able to read an analog clock in case a digital clock is not available. Midnight is written as 00:00 on the 24-hour clock. To convert the time from a 24-clock to that of a 12-hour clock, just subtract 12 if the hour number is greater than 12, and write "PM." If the hour on the 24-hour clock is smaller than 12, then write the same time along with an "AM." If the hour on the 24-hour clock is 12, then write the same time along with a "PM." The exception is midnight (12:00 AM on the 12-hour clock). Because of this, for a 12-hour clock, we need to write "AM" (before midday) or "PM" (after midday) after the time to be able to know whether the time is 10 in the morning (10:00 AM) or 10 at night (10:00 PM).Ī 24-hour clock removes the need for an AM and PM designation, since the hours count from 0 up to 23 with 0 being midnight and 23 being 11 PM. The difference between a 24 and 12-hour clock is simply that, assuming we have a 12-hour clock, the hours only count from 1 up to 12, then repeat again starting at 1. Analog clocks also commonly use Roman numerals in place of Arabic numerals (the numeral system used in most of the world today). Digital clocks can usually display both 24 and 12 hour clocks, while most analog clocks use 12-hour clocks (though analog clocks can also display both). Analog and digital clocks can be further differentiated into 24-hour or 12-hour clocks. Both analog and digital clocks are still very common today. There are many different ways to measure and read time. In everyday life, time is commonly measured in units of seconds, minutes, hours, days, weeks, months, and years, among others. Time is one of the seven fundamental physical quantities in the International System of Units (SI), which can be used to define other physical quantities, such as speed. There are also many philosphical discussions of time, but those will not be mentioned here.
Some scientists define time to be the progress of events that occur in an irreversible succession from the past, through the present, and into the future. Time is a familiar concept to everybody, yet very hard to define.