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Why the Date Line Zigzags Across the Pacific

6th grade nonfiction passage about the International Date Line: 228 words, six questions, an answer key and vocabulary.

6th grade nonfiction the International Date Line 228 words

Why the Date Line Zigzags Across the Pacific

Imagine crossing the Pacific Ocean on a ship. On the day you pass a certain invisible line, the calendar jumps. Sail west across it and you skip a day. Sail east and you get the same day again. That line is called the International Date Line.

The line is needed because the Earth spins, so it is morning in some places while it is night in others. Each time zone is about an hour from its neighbors. If you travel all the way around the world, you pass through every zone, and somewhere along the way the date has to change. Mapmakers placed the change in the Pacific, where there is mostly water and few people.

The Date Line runs roughly north to south along the 180 degree line of longitude, which is halfway around the globe from the Prime Meridian. But look at a map and you will see that it is not a straight line. It bends and steps around island groups and countries. This is because people who live close together would find it very strange to have one island on Monday and its neighbor on Tuesday. Their workplaces, schools, and families need to share the same date.

So the line follows the choices of the countries it passes. Those choices have shifted a few times over the years, which is why the Date Line zigzags.

Questions

  1. What happens when you sail west across the International Date Line? in the text

  2. Why does the date have to change somewhere on Earth? in the text

  3. Why did mapmakers place the line in the Pacific? in the text

  4. Along which line of longitude does the Date Line roughly run? in the text

  5. Why does the Date Line bend around islands? think about it

  6. Why might the zigzag shape change over time? think about it

Words to know

invisible
not able to be seen
zone
an area that is treated as one part
longitude
imaginary lines that run from pole to pole on a map
mapmakers
people who draw and design maps
zigzags
turns sharply left and right again and again
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 · 192 words · Flesch-Kincaid grade 3.6

Picture a ship crossing the Pacific Ocean. On the day it passes an invisible line, the calendar jumps. Sail west across the line and you skip a day. Sail east and you get the same day again. This is the International Date Line.

We need the line because the Earth spins. It is morning in some places while it is night in others. Each time zone is about one hour from the next. If you go all the way around the world, you pass through every zone. Somewhere the date has to change. Mapmakers put the change in the Pacific, where there is mostly water and few people.

The Date Line runs north to south, near the 180 degree line of longitude. But on a map it is not straight. It bends around islands and countries. People who live close together should share the same date. It would be odd for one island to have Monday while its neighbor has Tuesday. Schools, jobs, and families need the same day.

So the line follows the choices of the countries it passes. Those choices have changed a few times. That is why the line zigzags.

▲ This passage · 228 words · Flesch-Kincaid grade 5.7

Imagine crossing the Pacific Ocean on a ship. On the day you pass a certain invisible line, the calendar jumps. Sail west across it and you skip a day. Sail east and you get the same day again. That line is called the International Date Line.

The line is needed because the Earth spins, so it is morning in some places while it is night in others. Each time zone is about an hour from its neighbors. If you travel all the way around the world, you pass through every zone, and somewhere along the way the date has to change. Mapmakers placed the change in the Pacific, where there is mostly water and few people.

The Date Line runs roughly north to south along the 180 degree line of longitude, which is halfway around the globe from the Prime Meridian. But look at a map and you will see that it is not a straight line. It bends and steps around island groups and countries. This is because people who live close together would find it very strange to have one island on Monday and its neighbor on Tuesday. Their workplaces, schools, and families need to share the same date.

So the line follows the choices of the countries it passes. Those choices have shifted a few times over the years, which is why the Date Line zigzags.

■ Harder · 233 words · Flesch-Kincaid grade 9.6

Imagine sailing across the Pacific Ocean on a ship. On the day you cross a certain invisible boundary, the calendar suddenly leaps. Travel west across it and you lose an entire day, while traveling east gives you the same day a second time. That boundary is called the International Date Line.

Such a line is necessary because the Earth rotates, so it is morning in some regions while it is night in others. Each time zone differs from its neighbor by roughly an hour, and anyone who travels completely around the world passes through every zone. Somewhere along the journey the date must change, and mapmakers chose to place that change in the Pacific, where there is mostly open water and very few people.

The Date Line runs roughly north to south along the 180 degree line of longitude, which lies halfway around the globe from the Prime Meridian. A glance at a map, however, reveals that it is far from straight. It bends and steps around island groups and countries, since people who live close together would find it bewildering for one island to be on Monday while its nearest neighbor is on Tuesday. Workplaces, schools, and families all depend on sharing the same date.

The line therefore follows the decisions of the countries it passes, and those decisions have shifted several times over the years, which explains why the Date Line zigzags.

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 invisible, zone, longitude, mapmakers and zigzags 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 Date Line Zigzags Across the Pacific"?

It was written for 6th grade. It has 228 words and works out to a Flesch-Kincaid grade level of about 5.7. 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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