Scientists know that the brain is very active
READING AND WRITING
4 Read this article.
when a person is sleeping. There are foน
stages, or parts, of sleep.
Stage 1 starts after you fall asleep. If there
is a noise or a bright light, you wake up Verน
easily. In Stage 2, your brain waves are very
slow, and your body gets ready for deep
sleep. Stage 3 is deep sleep. It's very difficulk
to wake up then. Your body rests and grows
during this stage.
Stage 4 is when you dream. Your eyes move
a lot, and your brain waves are fast. This
Brain waves during sleep
stage of sleep is very important for your memory. After Stage 4, you wake up a little, and
then Stage 1 starts again. We go through the four stages of sleep four or five times every
night, so we have many dreams in one night.
How much sleep do you need? The answer depends on your age. Babies should sleep 15
to 16 hours every day. Children and teenagers need nine or ten hours of sleep, but older
people only need six to eight hours. If you sleep for only four hours one night, yoน may just
feel tired the next day. But many nights of bad sleep can be bad for your health. People who
don't get enough sleep get sick more often. And sleep is very important for learning. It's one
reason why students should go to bed early!
3 Answer the questions.
1. How many stages of sleep are there?
2. When do people dream?
3. How many times do we have Stage 1 sleep each night?
4. When does your body grow?
5. How much sleep do babies need?
6. Why shoนld students sleep a lot?
7. Look at the last paragraph again. How much sleep should you get?
8. Do you get enough sleep?
UNIT 6 The mind