- How many hours sleep in a day?
- How is 24 hours calculated?
- Why is 60 minutes an hour?
- What percentage is 2 hours out of 24?
- How long is 24 hours in a day?
- Why is one day and 24 hours one night?
- Is 9am to 9am 24 hours?
- Why is a day 24 hours?
- Who invented time?
- How long is 24hrs?
- Who decided 24 hour day?
- Why is a day 23 hours and 56 minutes?
- How many is 2 hours?
- Who many seconds are in a year?

## How many hours sleep in a day?

Most adults need 7 to 9 hours, although some people may need as few as 6 hours or as many as 10 hours of sleep each day.

Older adults (ages 65 and older) need 7-8 hours of sleep each day.

Women in the first 3 months of pregnancy often need several more hours of sleep than usual..

## How is 24 hours calculated?

There are two ways of telling the time: The 12-hour clock runs from 1am to 12 noon and then from 1pm to 12 midnight. The 24-hour clock uses the numbers 00:00 to 23:59 (midnight is 00:00).

## Why is 60 minutes an hour?

Who decided on these time divisions? THE DIVISION of the hour into 60 minutes and of the minute into 60 seconds comes from the Babylonians who used a sexagesimal (counting in 60s) system for mathematics and astronomy. They derived their number system from the Sumerians who were using it as early as 3500 BC.

## What percentage is 2 hours out of 24?

8.333333333333%Convert fraction (ratio) 2 / 24 Answer: 8.333333333333%

## How long is 24 hours in a day?

86,400 secondsBesides the day of 24 hours (86,400 seconds), the word day is used for several different spans of time based on the rotation of the Earth around its axis. An important one is the solar day, defined as the time it takes for the Sun to return to its culmination point (its highest point in the sky).

## Why is one day and 24 hours one night?

Why Does Earth Have Day and Night? While you don’t feel it, Earth is spinning. Once every 24 hours Earth turns — or rotates on its axis — taking all of us with it. When we are on the side of Earth that is facing the Sun, we have daylight.

## Is 9am to 9am 24 hours?

Note: The 24 hour Time Format variation on the normal 24 hour time….24-Hour Time Format.am/pm24-hour7am07:008am08:009am09:0010am10:0022 more rows

## Why is a day 24 hours?

Our 24-hour day comes from the ancient Egyptians who divided day-time into 10 hours they measured with devices such as shadow clocks, and added a twilight hour at the beginning and another one at the end of the day-time, says Lomb. “Night-time was divided in 12 hours, based on the observations of stars.

## Who invented time?

The measurement of time began with the invention of sundials in ancient Egypt some time prior to 1500 B.C. However, the time the Egyptians measured was not the same as the time today’s clocks measure. For the Egyptians, and indeed for a further three millennia, the basic unit of time was the period of daylight.

## How long is 24hrs?

Convert 24 Hours to Dayshrd24.00124.011.000424.021.000824.031.001396 more rows

## Who decided 24 hour day?

HipparchusHipparchus, whose work primarily took place between 147 and 127 B.C., proposed dividing the day into 24 equinoctial hours, based on the 12 hours of daylight and 12 hours of darkness observed on equinox days.

## Why is a day 23 hours and 56 minutes?

Not quite 24 hours, it turns out — it’s precisely 23 hours and 56 minutes. But because Earth is constantly moving along its orbit around the sun, a different point on the planet faces the sun directly at the end of that 360-degree spin. … “If we didn’t orbit the sun, both days would be the same.”

## How many is 2 hours?

In 2 h there are 120 min . Which is the same to say that 2 hours is 120 minutes.

## Who many seconds are in a year?

31,536,000 secondsone year would equal 365 times 24 times 60 times 60 seconds…or 31,536,000 seconds!