Diurnal cycle

A diurnal cycle is like having a special clock inside our body that tells us when it is time to be awake and when it is time to go to sleep.

Imagine when you go to bed, you close your eyes and sleep until your mom or dad wakes you up in the morning. This is because your body has a special clock that knows when it is bedtime and when it is time to wake up in the morning.

This clock works for animals and plants too, it makes them move, eat, sleep or wake up at certain times. It is called a diurnal cycle because it works in a cycle of 24 hours.

For example, some animals like lions and tigers are active during the day and sleep at night, while other animals like bats are active at night and sleep during the day.

The diurnal cycle is also affected by things like daylight and darkness. When it's dark outside, our bodies produce a chemical called melatonin which makes us feel sleepy. When the sun rises and there's light, our bodies produce less melatonin and we feel more awake.

So, a diurnal cycle is like a special clock in our body that tells us when to sleep and wake up, and it works in a cycle of 24 hours.