Conversion from 50 Seconds to Hours

Information about the Second (s)

The second is the base unit of time in the International System of Units. Its symbol is s. It is defined by fixing the frequency of the caesium-133 hyperfine transition at exactly 9,192,631,770 cycles per second, so a second is the duration of that many oscillations.

The name records a division that no longer exists in practice. Medieval astronomers divided the hour into sixty minutae primae, first small parts, and each of those into sixty minutae secundae, second small parts. English kept the first as minute and the second as second, leaving the ordinal in the name of a unit almost nobody thinks of as ordinal.

For most of history the second was defined from the rotation of the Earth, as one 86,400th of a mean solar day. That definition failed once clocks became better than the planet: the Earth's rotation is irregular, slowing over centuries from tidal friction and wobbling on shorter timescales. The atomic definition adopted in 1967 severed the link, which is why leap seconds are occasionally inserted to keep civil time aligned with the sun.

Every other time unit is now built on it, and the second underpins most of the rest of the SI as well. The metre is defined through the speed of light in metres per second, the kilogram through the Planck constant which carries a second in its units, and the ampere through the elementary charge per second. Caesium fountain clocks realise the unit to a few parts in ten to the sixteenth, and optical clocks now do better still.

Because atomic clocks keep better time than the planet does, the two have to be reconciled. The Earth's rotation is slowing irregularly, so a day is now a millisecond or two longer than 86,400 atomic seconds, and the difference accumulates. Since 1972 the answer has been the leap second: an extra second inserted at the end of a June or December, announced months in advance, which has happened twenty-seven times. Computer systems handle the repeated timestamp badly enough that outages have been traced to it, and in 2022 the world's metrology bodies voted to abandon the practice by 2035, letting civil time drift from solar time instead.

One second equals 1000 milliseconds, one sixtieth of a minute, or about 0.000277778 hours.

Information about the Hour (hr)

The hour is a unit of time equal to 60 minutes, or 3600 seconds. Its symbol is h, though hr is common in English-language informal use. Twenty-four hours make a day, and the unit is accepted for use with the SI without belonging to it.

Its length was once variable. Ancient Egyptian and later Greco-Roman practice divided daylight into twelve parts and darkness into twelve more, which meant an hour of daylight in summer was considerably longer than one in winter. These seasonal or temporal hours persisted in Europe into the medieval period and were still used in monastic timekeeping long after mechanical clocks appeared. Equal hours won out because a clock cannot easily be made to run at a rate that changes with the season.

Twenty-four is the count because twelve is the count. Egyptian astronomers used a set of thirty-six decan stars, of which twelve were visible across a night, and twelve was already a convenient number in a duodecimal counting tradition that divides cleanly by two, three, four and six. Doubling it to cover the day gave twenty-four, and no serious attempt to change it has succeeded since.

The hour organises modern working life more than any other unit. Wages, shifts, opening times, flight durations, parking charges and legal limits on driving are all expressed in hours, and the hour is the base of the kilowatt-hour, which is how virtually all electricity is billed. Timetables are built on hour boundaries, and time zones are defined as whole-hour offsets from Coordinated Universal Time, with a handful of exceptions offset by thirty or forty-five minutes.

In science the hour appears less often than the second but survives wherever a process runs long enough to make seconds unwieldy: reaction times in chemistry, dosing intervals in medicine, and half-lives in the range where hours are the natural scale.

Geography is divided by it. The Earth turns fifteen degrees of longitude in an hour, so the globe was cut into twenty-four zones an hour apart, a scheme adopted at the International Meridian Conference of 1884 after railways made local solar time unworkable. The tidiness is partial: several countries keep offsets of half an hour or forty-five minutes, and China spans five geographic zones on a single one. The hour also lends its name to a unit of energy. A kilowatt-hour is the energy delivered by a kilowatt for an hour, 3.6 megajoules, and it is the quantity on every electricity bill in the world.

One hour equals 60 minutes, 3600 seconds, or about 0.0416667 days.