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The Slingshot That Saves Rocket Fuel

5th grade nonfiction passage about gravity assist for spacecraft: 226 words, six questions, an answer key and vocabulary.

5th grade nonfiction gravity assist for spacecraft 226 words

The Slingshot That Saves Rocket Fuel

A spacecraft that heads for the far planets has a problem. Rocket fuel is heavy, and the farther a ship needs to go, the more fuel it needs to carry. Engineers found a clever way to save some. They let a planet give the spacecraft a push.

The method is called a gravity assist. Planets pull on everything near them with gravity. When a spacecraft flies close to a planet, it is pulled toward it and swings around it, much like a runner swinging around a pole. As the spacecraft leaves, it can be moving faster and heading in a new direction. The planet gives the ship a little of its own motion along its path around the sun.

Does the planet slow down? It does, but the change is far too small to notice, because a planet is enormously heavier than a spacecraft. The spacecraft gains speed, and the planet hardly changes at all.

Gravity assists let spacecraft reach places that would take too much fuel to get to by engine alone. The Voyager spacecraft used the pull of the giant planets to travel from one to the next. Mission planners must aim very carefully, because passing too far from a planet gives little help, and passing too near could be dangerous. When it works, a planet becomes a free boost on a long journey.

Questions

  1. Why is carrying a lot of rocket fuel a problem? in the text

  2. What is the method called that uses a planet to push a spacecraft? in the text

  3. What does a spacecraft gain from a gravity assist? in the text

  4. Why does the planet not seem to slow down? think about it

  5. Why must planners aim carefully? think about it

  6. Which spacecraft used the pull of the giant planets? in the text

Words to know

engineers
people who design and build machines and tools
gravity
the force that pulls objects toward each other
enormously
to a very great degree
boost
a push that helps something go faster
mission
a special job or trip with a goal
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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 · 189 words · Flesch-Kincaid grade 3.9

A spacecraft that goes to the far planets has a problem. Rocket fuel is heavy. The farther a ship goes, the more fuel it needs. Engineers found a clever way to save some. They let a planet give the ship a push.

This is called a gravity assist. Planets pull on everything near them with gravity. When a spacecraft flies close to a planet, it is pulled in and swings around, like a runner swinging around a pole. When it leaves, it can be going faster and in a new direction. The planet gives the ship a little of its own motion around the sun.

Does the planet slow down? It does, but the change is far too small to notice. A planet is much, much heavier than a spacecraft.

Gravity assists let ships reach places that need too much fuel by engine alone. The Voyager spacecraft used the pull of the giant planets to go from one to the next. Planners must aim with great care. Too far from a planet gives little help. Too near could be dangerous. When it works, a planet is a free boost.

▲ This passage · 226 words · Flesch-Kincaid grade 6.6

A spacecraft that heads for the far planets has a problem. Rocket fuel is heavy, and the farther a ship needs to go, the more fuel it needs to carry. Engineers found a clever way to save some. They let a planet give the spacecraft a push.

The method is called a gravity assist. Planets pull on everything near them with gravity. When a spacecraft flies close to a planet, it is pulled toward it and swings around it, much like a runner swinging around a pole. As the spacecraft leaves, it can be moving faster and heading in a new direction. The planet gives the ship a little of its own motion along its path around the sun.

Does the planet slow down? It does, but the change is far too small to notice, because a planet is enormously heavier than a spacecraft. The spacecraft gains speed, and the planet hardly changes at all.

Gravity assists let spacecraft reach places that would take too much fuel to get to by engine alone. The Voyager spacecraft used the pull of the giant planets to travel from one to the next. Mission planners must aim very carefully, because passing too far from a planet gives little help, and passing too near could be dangerous. When it works, a planet becomes a free boost on a long journey.

■ Harder · 243 words · Flesch-Kincaid grade 9.5

A spacecraft bound for the distant planets confronts a serious difficulty. Rocket fuel is extremely heavy, and the farther a ship must travel, the more fuel it is required to carry. Engineers devised an ingenious method of saving some of it: they allow a planet to give the spacecraft a push.

The technique is known as a gravity assist. Planets pull on everything in their vicinity through the force of gravity. When a spacecraft passes close to a planet, it is drawn toward the planet and swings around it, much like a runner whipping around a pole. As the spacecraft departs, it may be traveling faster and heading in an entirely new direction, because the planet has transferred a small portion of its own motion along its path around the sun.

Does the planet slow down as a result? It does, but the change is far too tiny to detect, since a planet is immensely heavier than any spacecraft. The ship gains speed, while the planet is scarcely affected.

Gravity assists enable spacecraft to reach destinations that would demand too much fuel if they relied on engines alone. The Voyager spacecraft used the pull of the giant planets to travel from one to the next. Mission planners must aim with remarkable precision, because passing too far from a planet provides little help, and passing too near could be hazardous. When everything goes well, a planet becomes a free boost on a long journey.

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 engineers, gravity, enormously, boost and mission 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 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 "The Slingshot That Saves Rocket Fuel"?

It was written for 5th grade. It has 226 words and works out to a Flesch-Kincaid grade level of about 6.6. 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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