Time: seconds, hours and days
๐ In short
When do we wake up? How long does the lesson last? How long until Eid? We can't see or touch time, but we measure it with clocks and calendars. All its units come from the movement of the Earth and the Moon: the day, the month and the year.
๐คฉ Did you know?
- There are 86400 seconds in a day.
- The Hijri year is about 354 days, about 11 days shorter than the solar year.
- About every 4 years there's a leap year with 366 days, when February has 29 days.
- Al-Jazari, a Muslim engineer, invented amazing water clocks more than 800 years ago.
๐ Find out more
๐ From seconds to hours
A second is very short, like calmly saying โoneโ. A minute is 60 seconds, and an hour 60 minutes. We inherited this counting in sixties from the Babylonians thousands of years ago.
๐ The day
A day is 24 hours, the time the Earth takes to spin all the way round once. The half of the Earth facing the Sun has daytime, and the other half has night.
๐ก Weeks, months and years
A week is 7 days. A lunar month, from one new crescent moon to the next, is about 29 or 30 days. A solar year is 365 days, the time the Earth takes to go round the Sun, and it has 12 months.
๐ฏ Telling the time
The short hour hand goes round twice a day, and the long minute hand goes round once an hour. When the long hand points to 3 we say โquarter pastโ, to 6 โhalf pastโ, and to 9 โquarter toโ.
๐งฎ Worked examples
- 2 hours = 120 minutes2 ร 60.
- 3 days = 72 hours3 ร 24.
- From 8:30 to 10:00 = an hour and a halfFrom 8:30 to 9:30 is an hour, then 30 minutes.
๐ Key words
- Minute
- 60 seconds
- Calendar
- A chart that sets out the days and months of the year
- Leap year
- A year with 366 days instead of 365
๐งช Try it at home
Make an hourglass from two small bottles and a little fine sand. How many seconds does it take for all the sand to fall? Use it to time brushing your teeth.
๐งฉ Test yourself
1 How many minutes are in an hour?
2 How many hours are in a day?
3 How many days are in a week?