24 is a unit of time measurement that divides one day into 24 equal parts. It is based on the Earth’s rotation around its axis in relation to the Sun, which takes approximately 24 hours. This system was first used by ancient Babylonians and Egyptians who divided their days into 12 double-hours each, with an hour being 1/12th of daylight and another 1/12th of night-time.

The modern definition of a 24 hour period has been standardized worldwide since 1972 as 86 400 seconds or 86400 SI base units (the International System). This allows for precise measurements when dealing with international time zones, where some regions may use Daylight Saving Time while others do not.

Furthermore, it ensures uniformity across all countries so that everyone can keep track of what time it is regardless if they are at home or abroad.

In addition to keeping track of daily activities such as work schedules and school classes, the concept behind this unit also applies to other aspects like measuring temperature changes over periods longer than one day – for example meteorologists often refer to “24-hour temperature” when talking about how much temperatures have changed during any given period within a single day cycle from midnight until midnight again on the following day(s).

As you can see there are many practical applications for understanding this simple yet powerful concept!