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Why the Clock Jumps on a Flight East

6th grade nonfiction passage about time zones and elapsed time: 219 words, six questions, an answer key and vocabulary.

6th grade nonfiction time zones and elapsed time 219 words

Why the Clock Jumps on a Flight East

Dev boards a plane at 9:00 in the morning for a five hour flight to the east. When the plane finally lands, his watch still shows 2:00 in the afternoon, but the clock on the airport wall says 4:00, and nobody has made an error, because Dev has crossed into a new time zone.

Earth spins once about every 24 hours, and one full turn is 360 degrees. Dividing 360 by 24 gives 15, so the sun appears to move across 15 degrees of sky each hour, and mapmakers use this fact to divide the world into time zones that are each roughly 15 degrees wide. Traveling east from one zone into the next adds an hour to the clock, while traveling west takes an hour away.

Real zones are not perfectly neat. Their borders often follow state lines, rivers, and country borders so that neighbors can share the same time. Because of this, some zones are much wider than others.

Back to Dev. The clocks in his new city run two hours ahead of the clocks at home. To find the local arrival time, he adds the 5 hours of flying to the 9:00 start, then adds the 2 hours of difference. Nine plus five plus two makes 16, which is 4:00 in the afternoon. The elapsed time, meaning the time that really passed, is still just five hours. Only the clock changed.

Questions

  1. What time did the airport wall clock show when Dev landed? in the text

  2. How many degrees does the sun appear to cross each hour? in the text

  3. What happens to the clock when you travel east into the next zone? in the text

  4. Why are some time zones wider than others? in the text

  5. Why did Dev's watch and the airport clock disagree? think about it

  6. How long did Dev's trip really take in elapsed time? think about it

Words to know

zone
an area of the world that shares the same clock time
degrees
units used to measure parts of a circle
elapsed
having passed, as in time that goes by
borders
the lines that separate one place from another
arrival
the act of getting to a place
Share

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 · 162 words · Flesch-Kincaid grade 0.9

Dev gets on a plane at 9:00 in the morning. The flight goes east and lasts five hours. When he lands, his watch says 2:00. The clock on the airport wall says 4:00. No one made a mistake. Dev is in a new time zone.

Earth spins once in about 24 hours. A full turn is 360 degrees. Divide 360 by 24 and you get 15. So the sun seems to move 15 degrees each hour. Mapmakers use this to make time zones. Each zone is about 15 degrees wide. Going east into the next zone adds an hour to the clock. Going west takes an hour away.

Real zones are not so neat. Their borders often follow state lines, rivers, and country borders. This lets neighbors share the same time. So some zones are wider than others.

Dev's new city is two hours ahead of home. He adds 5 hours of flying to 9:00. Then he adds 2 hours. That makes 16, or 4:00 in the afternoon. The time that really passed is still five hours.

▲ This passage · 219 words · Flesch-Kincaid grade 5.4

Dev boards a plane at 9:00 in the morning for a five hour flight to the east. When the plane finally lands, his watch still shows 2:00 in the afternoon, but the clock on the airport wall says 4:00, and nobody has made an error, because Dev has crossed into a new time zone.

Earth spins once about every 24 hours, and one full turn is 360 degrees. Dividing 360 by 24 gives 15, so the sun appears to move across 15 degrees of sky each hour, and mapmakers use this fact to divide the world into time zones that are each roughly 15 degrees wide. Traveling east from one zone into the next adds an hour to the clock, while traveling west takes an hour away.

Real zones are not perfectly neat. Their borders often follow state lines, rivers, and country borders so that neighbors can share the same time. Because of this, some zones are much wider than others.

Back to Dev. The clocks in his new city run two hours ahead of the clocks at home. To find the local arrival time, he adds the 5 hours of flying to the 9:00 start, then adds the 2 hours of difference. Nine plus five plus two makes 16, which is 4:00 in the afternoon. The elapsed time, meaning the time that really passed, is still just five hours. Only the clock changed.

■ Harder · 222 words · Flesch-Kincaid grade 7.1

Dev boards an airplane at nine o'clock in the morning for a flight of five hours toward the east. When the plane touches down, his watch still reads 2:00 in the afternoon, yet the clock mounted on the airport wall says 4:00. Nobody has made an error; Dev has simply crossed into a new time zone.

Earth rotates once about every 24 hours, and a complete rotation measures 360 degrees. Dividing 360 by 24 yields 15, so the sun appears to travel across 15 degrees of sky every hour. Mapmakers rely on this fact to divide the world into time zones, each of which is roughly 15 degrees wide. Traveling eastward from one zone into the next adds an hour to the clock, whereas traveling westward subtracts one.

In practice, the zones are not perfectly tidy. Their borders frequently follow state lines, rivers, and country borders so that neighboring communities can share the same time. As a consequence, some zones are considerably wider than others.

Returning to Dev, the clocks in his destination run two hours ahead of those at home. To calculate the local arrival time, he adds the 5 hours of flying to the 9:00 departure, and then adds the 2 hours of difference. Nine plus five plus two equals 16, which is 4:00 in the afternoon. The elapsed time, meaning the time that genuinely passed, remains five hours. Only the clock has changed.

Download as one PDF

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 zone, degrees, elapsed, borders and arrival 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 2 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 5 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 the Clock Jumps on a Flight East"?

It was written for 6th grade. It has 219 words and works out to a Flesch-Kincaid grade level of about 5.4. 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 six. 4 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 2 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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