Read

There are two basic types of sleep: non-REM sleep, which has three stages, and REM sleep. During the night you go through stage 1, 2 and 3 and then REM, and this cycle repeats several times. The first REM sleep starts about 90 minutes after you fall asleep.

In stage 1 your heartbeat and breathing slow and your muscles relax. In stage 2 your brain waves slow and your body temperature drops. Stage 3 is deep sleep: heartbeat and breathing are at their lowest, and your body grows and repairs tissue.

In REM sleep (rapid eye movement) your brain is very active, your breathing is fast and irregular, your eyes dart back and forth and you dream. Your arm and leg muscles are temporarily paralysed, which stops you acting out your dreams.

Experiment: Anonymous class sleep survey

1. Agree the question: 'About how many hours did you sleep last school night?' Everyone answers for the same night.
2. Each person writes only a number of hours on a slip (no names) and folds it. Writing nothing is fine too.
3. Collect the slips in the box and mix them.
4. Sort the slips into groups: under 8 h, 8–9 h, 9–10 h, 10–11 h, 11 h or more.
5. Draw a bar chart. How many slips are in the 9 to 12 hour range?
6. Discuss: what makes this a fair survey? What could make the answers less accurate?

Hours slept	Number of slips	Tally
Under 8 h
8–9 h
9–10 h
10–11 h
11 h or more

Questions

1. Put one sleep cycle in order: REM, stage 1, stage 3, stage 2.

2. Class survey: how many slips were in the 9 to 12 hour range, out of how many?

3. Explain why a cola or coffee late in the day can make it harder to fall asleep.

4. Give two tips for a good night's sleep and explain one of them.

Sources for every fact on this sheet: echoesof.science/school/sleep/sources/

🖨 Print this sheet ← back to the lesson