Chapter 03 of 5
The Body's Clock
The inner timekeeper that runs your days — and the Nobel Prize that explained it.
- The Word
About a day
'Circadian' comes from Latin words meaning 'about a day' — describing rhythms that repeat roughly every 24 hours.
- 1729
A plant in the dark
French scientist Jean-Jacques d'Ortous de Mairan noticed a plant kept opening and closing its leaves on schedule even in constant darkness.
- The Insight
An internal clock
That meant living things carry their own internal clock, rather than simply reacting to sunlight.
17 more cards in this chapter
Could you answer this?
The 2017 Nobel Prize-winning research on body clocks was mainly done in which animal?
😴 The Science of Sleep
- 01Why We Sleep at AllWe spend a third of our lives asleep. Here's what it's for.
- 02Inside a NightSleep cycles, REM and the strange world of dreams.
- 03The Body's ClockThe inner timekeeper that runs your days — and the Nobel Prize that explained it.
- 0411 Days AwakeThe teenager who stayed awake for 264 hours — and what sleep loss does.
- 05Owls, Larks and Jet LagMorning people, night owls, and working with your own clock.