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Why Teen Sleep Clocks Run Late

8th grade nonfiction passage about teenagers and sleep timing: 268 words, seven questions, an answer key and vocabulary.

8th grade nonfiction teenagers and sleep timing 268 words

Why Teen Sleep Clocks Run Late

Many teenagers complain that they cannot fall asleep at ten o'clock, and then they struggle to wake up for an early class. Adults often blame screens or laziness, but sleep researchers have found a biological reason too. During the teen years, the body's internal clock shifts later.

The clock is a small cluster of cells in the brain that keeps a daily rhythm of about twenty-four hours, called the circadian rhythm. Light is its main cue. In the evening, darkness signals the brain to release melatonin, a hormone that makes the body ready for sleep. During puberty, melatonin tends to rise later at night than it did in childhood. A teenager may not feel truly sleepy until eleven o'clock or later, even after a long day.

This would be harmless if school started late. Many schools begin early in the morning, however, which forces a teen to wake while the body is still in its night mode. Over a week, the missing sleep adds up. Teens generally need somewhere around eight to ten hours a night, and studies connect too little sleep with trouble concentrating and a low mood.

Some school districts have tried later start times, and several studies report that their students slept more. In the meantime, certain habits help. Keeping a steady wake-up time, even on weekends, anchors the clock. Bright light in the morning pulls it earlier, while dim lights and fewer glowing screens in the last hour before bed let melatonin do its work. Sleep is not a luxury for a growing body. It is part of how the body grows.

Questions

  1. What is the circadian rhythm? in the text

  2. Which hormone does the brain release when darkness arrives? in the text

  3. What happens to the timing of melatonin during puberty? in the text

  4. Why is an early school start hard on many teenagers? think about it

  5. About how many hours of sleep do teens generally need? in the text

  6. Which two habits help a teenager's sleep clock? in the text

  7. Why is blaming laziness only part of the story? think about it

Words to know

circadian
following a daily cycle of about twenty-four hours
melatonin
a hormone that helps the body get ready for sleep
hormone
a chemical messenger made in the body
puberty
the years when a child's body grows into an adult's
anchors
holds something steady so it does not drift
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One passage, three levels

The same topic and facts written three ways, so a mixed class can read and talk about one text. Each group’s sheet shows only a shape; the key says which is which.

● Easier · 222 words · Flesch-Kincaid grade 2.9

Many teens cannot fall asleep at ten o'clock. Then they have a hard time waking up for early class. Some adults blame screens or laziness. But scientists found another reason. In the teen years, the body clock moves later.

The clock is a small group of cells in the brain. It keeps a daily rhythm of about twenty-four hours. This is called the circadian rhythm. Light is its main cue. At night, darkness tells the brain to make melatonin. Melatonin is a hormone that helps you get ready for sleep. In puberty, melatonin comes later at night than it did before. A teen may not feel sleepy until eleven o'clock or later.

That is fine if school starts late. But many schools start early. A teen has to wake up when the body still thinks it is night. The lost sleep adds up over a week. Teens need about eight to ten hours a night. Too little sleep makes it hard to focus. It can also lead to a low mood.

Some schools tried later start times. Studies say the students slept more. There are also habits that help. Wake up at the same time every day, even on weekends. Get bright light in the morning. Dim the lights and use fewer screens before bed. Sleep helps a growing body grow.

▲ This passage · 268 words · Flesch-Kincaid grade 7.2

Many teenagers complain that they cannot fall asleep at ten o'clock, and then they struggle to wake up for an early class. Adults often blame screens or laziness, but sleep researchers have found a biological reason too. During the teen years, the body's internal clock shifts later.

The clock is a small cluster of cells in the brain that keeps a daily rhythm of about twenty-four hours, called the circadian rhythm. Light is its main cue. In the evening, darkness signals the brain to release melatonin, a hormone that makes the body ready for sleep. During puberty, melatonin tends to rise later at night than it did in childhood. A teenager may not feel truly sleepy until eleven o'clock or later, even after a long day.

This would be harmless if school started late. Many schools begin early in the morning, however, which forces a teen to wake while the body is still in its night mode. Over a week, the missing sleep adds up. Teens generally need somewhere around eight to ten hours a night, and studies connect too little sleep with trouble concentrating and a low mood.

Some school districts have tried later start times, and several studies report that their students slept more. In the meantime, certain habits help. Keeping a steady wake-up time, even on weekends, anchors the clock. Bright light in the morning pulls it earlier, while dim lights and fewer glowing screens in the last hour before bed let melatonin do its work. Sleep is not a luxury for a growing body. It is part of how the body grows.

■ Harder · 278 words · Flesch-Kincaid grade 9.6

Countless teenagers complain that they cannot drift off at ten o'clock and then struggle to wake up in time for an early class. Adults frequently blame screens or laziness, but sleep researchers have uncovered a biological explanation as well. Throughout the teenage years, the body's internal clock shifts toward later hours.

That clock is a small cluster of brain cells that maintains a daily rhythm of roughly twenty-four hours, known as the circadian rhythm. Light is its primary cue. When evening darkness arrives, the brain releases melatonin, a hormone that prepares the body for sleep. During puberty, melatonin tends to appear later at night than it did in childhood, so a teenager may not feel genuinely sleepy until eleven o'clock or afterward, even following a long and tiring day.

Such a pattern would be harmless if school began late in the morning. Many schools start early, however, which forces a teenager to wake while the body is still operating in its night mode. Across a single week, the missing sleep accumulates. Teenagers generally need somewhere around eight to ten hours each night, and studies have connected insufficient sleep with difficulty concentrating and with a low mood.

A number of school districts have experimented with later start times, and several studies report that their students slept more. Meanwhile, particular habits can help. Maintaining a consistent wake-up time, even on weekends, anchors the clock. Bright light in the morning nudges it earlier, whereas dim lighting and fewer glowing screens during the final hour before bed allow melatonin to do its work. Sleep is not a luxury for a growing body. It is part of how the body grows.

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How to use it

  1. Press Read it big (or B) to put the text on the projector, or Full screen (F) to fill the whole screen.
  2. Ask the questions one at a time and use Show answer when the class has decided. A shows or hides every answer.
  3. Print student copy for the class, or Print with answers for yourself.

Ideas for class

  • Before reading, put circadian, melatonin, hormone, puberty and anchors on the board with their meanings from the Words to know section and have students predict what the text will be about.
  • Read it aloud once while students follow along, then have them reread it alone or with a partner. At a calm 100 words a minute it takes about 3 minutes to read aloud.
  • Use the Read it big button (or B) to put the text on the projector, and Show answer on one question at a time so the class commits to an answer first.
  • Question 4 asks the reader to infer. Ask students to point to the words in the passage that led them to their answer.
  • Ask students to write one question the passage did not answer, then look for the answer in a book or on a classroom screen.
  • Print the student copy for independent work and keep the answer-key copy for yourself.

Related

Questions

What reading level is "Why Teen Sleep Clocks Run Late"?

It was written for 8th grade. It has 268 words and works out to a Flesch-Kincaid grade level of about 7.2. That is a formula's estimate from sentence length and syllables, and it is not a Lexile or a guided reading level, so check it against your students.

What do the questions ask?

There are seven. 5 ask for something the text says directly and 2 ask the reader to work something out from clues. Each has an answer in the key, and the answers are written as a teacher would accept them, not as the only possible wording.

How long does it take to read?

About 3 minutes read aloud at 100 words a minute. For a one-minute fluency check, paste it into the fluency timer and use the word count.

Can I print it?

Yes. Print student copy gives the passage, the questions with lines to write on, and the word meanings. Print with answers gives the same page with the answers filled in. Both are made in your browser.

Is this passage from a published book?

No. It was written for Peabody Teach, so there is no book to buy and no login to read it.

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