Conversion from 10 Hours to Milliseconds

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.

Information about the Millisecond (ms)

The millisecond is a unit of time equal to one thousandth of a second. Its symbol is ms. It is the shortest interval that people encounter by name in everyday life, largely because computing and networking made it a household measurement.

Human perception sets the scale that makes it interesting. The eye fuses separate images into motion somewhere around forty milliseconds apart, which is why cinema at twenty-four frames a second works. Audio is far less forgiving: a delay of more than about ten milliseconds between a musician's action and the sound they hear is enough to disrupt playing, and stereo direction is judged from arrival-time differences between the ears of well under one millisecond.

Network latency is quoted in milliseconds and is the number that determines whether a connection feels responsive. Light travels about three hundred kilometres in a millisecond in fibre, so intercontinental round trips have an irreducible floor: London to New York cannot go below roughly sixty milliseconds no matter how much is spent on equipment. Competitive online gaming, financial trading and video calling are all shaped by that limit.

Reaction time is measured in the same unit. A trained sprinter responds to a starting gun in around 150 milliseconds, and athletics rules treat anything below 100 milliseconds as a false start on the grounds that no human can react faster. Simple visual reaction times in a laboratory typically fall between 200 and 250 milliseconds.

Computing uses milliseconds as the natural unit for anything involving storage or human interaction. A mechanical hard disk seeks in several milliseconds while a solid-state drive answers in a fraction of one, a difference of two orders of magnitude that explains most of the change in how computers feel over the last two decades. Timestamps in most programming environments count milliseconds since the start of 1970.

Photography borrows it for shutter speeds, where a thousandth of a second is a common setting for freezing motion, and physiology uses it for the duration of a nerve impulse, which lasts one to two milliseconds.

One millisecond equals 0.001 seconds, 1000 microseconds, or one 3,600,000th of an hour.