--- title: Sleep and the body clock — a lesson of Mova's school · trees and pragmatics description: «Sleep and the body clock», a lesson of the world course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: Your body has its own clock, called the body clock or circadian rhythm ("about a day"), which runs on about 24 hours. --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/) [home](https://md.mova.elamur.ai/free/en/) / [corpora](https://md.mova.elamur.ai/free/en/corpora/) / [school](https://md.mova.elamur.ai/free/en/corpora/school/) / [World](https://md.mova.elamur.ai/free/en/corpora/school/world/) / Sleep and the body clock # Sleep and the body clock Lesson 127 of the world course of Mova's primary school: 23 sentences, each with its syntax tree and pragmatics. The lessons are written for Mova, and their agreed trees are part of Mova corpus 0.4 (CC BY-SA 4.0). How Mova does on its tests: [the lesson at school](https://md.mova.elamur.ai/free/en/school-run/world/127-sleep-and-the-body-clock/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/0/) — Your body has its own clock, called the body clock or circadian rhythm ("about a day"), which runs on about 24 hours. - [1](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/1/) — Morning light sets it each day, and getting up at the same time trains it, which is why Mia's body wakes her at 7 even on Saturdays with no alarm. - [2](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/2/) — Sleep is not wasted time: while you sleep, your growing body and brain do important work, sorting what you learned and repairing. - [3](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/3/) — Children aged 6 to 12 need about 9 to 12 hours a night, teenagers about 8 to 10, adults about 7 to 9, and newborn babies 14 to 17 hours, in short pieces. - [4](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/4/) — To choose a bedtime, count back from your wake-up time: up at 7 am and needing 10 hours means asleep by 9 pm. - [5](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/5/) — Bright screens in bed tell the brain "it's still day", so it makes less melatonin, the sleep chemical, and next day you're dead on your feet. - [6](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/6/) — In teenagers the body clock shifts later, so they feel sleepy late and hate mornings: partly biology, not just laziness. - [7](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/7/) — Fly across time zones and your body clock stays at home; that's jet lag, and flying east is often harder, because you must sleep earlier than your body wants. - [8](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/8/) — Almost all living things keep time like this, even flowers that open in the morning and close in the evening. - [9](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/9/) — Scientists who found out how body clocks work won the Nobel Prize in 2017. - [10](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/10/) — The body clock, or circadian rhythm, runs on about 24 hours, matching one spin of the Earth. - [11](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/11/) — Morning light sets the body clock, and getting up at the same time each day trains it. - [12](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/12/) — Children aged 6 to 12 need about 9 to 12 hours of sleep a night; adults need about 7 to 9. - [13](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/13/) — Teenagers need about 8 to 10 hours, but their body clock shifts later, so they feel sleepy later at night. - [14](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/14/) — Newborn babies sleep about 14 to 17 hours a day, waking every 2 to 3 hours to feed. - [15](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/15/) — Bright screens at night make the brain release less melatonin, the body chemical that helps sleep. - [16](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/16/) — Sleep from 8:30 pm to 7:00 am is 10 hours 30 minutes; to sleep 10 hours and wake at 7 am, you must fall asleep at 9 pm. - [17](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/17/) — Too little sleep makes it harder to concentrate, learn and stay in a good mood. - [18](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/18/) — Jet lag happens when the body clock doesn't match the local clock after flying across time zones; flying east is often harder. - [19](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/19/) — Los Angeles is 8 hours behind London, so 3 pm in Los Angeles is 11 pm in London. - [20](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/20/) — Tokyo is 9 hours ahead of London in British winter, so 3 am in London is noon in Tokyo. - [21](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/21/) — Missing a whole night's sleep makes people slow, grumpy and clumsy, and lost sleep can't really be caught up in one go. - [22](https://md.mova.elamur.ai/free/en/corpora/school/world/127-sleep-and-the-body-clock/22/) — Almost all living things have body clocks, even plants and bacteria; scientists who found how they work won the Nobel Prize in 2017. - ← previous: ["In the olden days": Grandad's 1990](https://md.mova.elamur.ai/free/en/corpora/school/world/126-in-the-olden-days/) - next →: [Growing up: ages of people and pets, and the "dog years" myth](https://md.mova.elamur.ai/free/en/corpora/school/world/128-growing-up-ages-dog-years/) - ↑ back to [World](https://md.mova.elamur.ai/free/en/corpora/school/world/)