The first to move the hands one hour forward in the spring and back in the fall were in Great Britain, starting in 1908. Today, about 110 countries of the world, located in relatively high-latitude regions of the globe, are doing this. The procedure increases daylight hours by an hour, thus saving energy costs. Equatorial states do not need such a measure, since the length of the day does not change significantly during the year.
Ecliptic and the change of seasons
The Earth, circling the Sun in about 365 days, makes a revolution around its own axis every 24 hours (again approximately). As a result, people observe the change of day and night. And how do the seasons change? The fact is that while revolving around the Sun and its axis, the Earth still performs a pendulum swing, tilting its axis towards the Sun by twenty-three and a half degrees and then deviating by the same angle. This angle is called the angle of the ecliptic. The full cycle takes place in one revolution in orbit - 365 days. Thus, in the zone of the greatest availability of solar radiation, heat and light, there is either the northern hemisphere, then the southern one. At the peak of the ecliptic in high latitudes, polar days or nights are even set. In more temperate latitudes, winter is characterized by long nights, and summer by long daylight hours.
The longest and shortest day of the year is called the summer and winter solstice, respectively. In the northern hemisphere, they fall on June 21 and December 21. In the southern hemisphere, the opposite is true.
Why translate the clock
All life on earth in its activity obeys daily rhythms. In the vast majority of plants and animals, including humans, activity manifests itself with the onset of the day. Farmers of antiquity began all their work with the rising of the sun, and the clock, as a mechanism, was of no use to them. Even now, rural residents are guided by daylight when carrying out field work. However, the factory industry is not strictly tied to natural phenomena. Work in workshops with artificial lighting, around the clock, is tied to the exact time only in terms of the fact that workers and engineers come to their workplaces at the same time. Interindustry, state, and now interstate relations require a single counting of time. Therefore, it is necessary that, on a national scale, at enterprises and institutions, the working day begins and ends at the same time.
It would seem that schedule the beginning of classes in a particular school not at 8.30, but at 9.30, so that the children do not go through the winter darkness, who have not yet woken up. But in the morning angry telephones from the RONO will already ring, general events will not be scheduled.
When to translate
In the relative motion of the Sun along the Earth's ecliptic there are moments when its position is above the equator, at the zero parallel. This happens twice a year - on the day of the vernal and autumnal equinoxes. After the day of the vernal equinox (March 21), the day begins to arrive, and it's time to move the hands one hour forward. To facilitate entry into the new regime, this is done at 2 am on the last Sunday in March. Likewise, after the day of the autumnal equinox (October 23), when the day begins to decrease, on the last Sunday in October, the clock hands at 3 am local time return to the true standard time.
