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Why the Bicycle Pump Gets Warm as You Pump

6th grade nonfiction passage about gases and heat: 215 words, six questions, an answer key and vocabulary.

6th grade nonfiction gases and heat 215 words

Why the Bicycle Pump Gets Warm as You Pump

After you inflate a bicycle tire with a hand pump, touch the lower part of the pump. It feels warm. You did not plug it in or heat it, so where did the warmth come from? The answer shows how closely energy and heat are connected.

Air is a gas made of countless molecules zooming around and bumping into one another. They move faster when the air is hotter and slower when it is colder. When you push the pump handle down, you squeeze the air into a smaller space. The plunger meets the molecules as they bounce off it, and like a bat hitting a ball, it sends them away faster than they arrived.

As a result, the squeezed air has molecules with more energy, and its temperature goes up. The work your arms did has become heat. Part of the warmth also comes from the plunger rubbing against the inside of the pump, because friction always makes some heat.

The effect is small on a bicycle pump, but it matters in bigger machines. A diesel engine squeezes air so hard that the air becomes hot enough to ignite the fuel sprayed into it, with no spark needed. When squeezed air is allowed to spread out again, the opposite happens, and it cools down.

Questions

  1. What happens to the air when you push the pump handle down? in the text

  2. Why do the molecules in squeezed air have more energy? in the text

  3. Besides squeezing the air, what else makes warmth in the pump? in the text

  4. How does a diesel engine use this idea? in the text

  5. Where does the energy that warms the air come from? think about it

  6. What do you think happens to the temperature of air that is allowed to spread out again? think about it

Words to know

inflate
to fill something up with air
molecules
the tiny particles that everything is made of
plunger
a part that slides back and forth inside a tube
friction
the rubbing force between two surfaces that touch
temperature
a measure of how hot or cold something is
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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 · 207 words · Flesch-Kincaid grade 2.6

Pump up a bicycle tire with a hand pump. Then touch the lower part of the pump. It feels warm. You did not plug it in. You did not heat it. So where did the warmth come from? The answer shows how energy and heat are linked.

Air is a gas. It is made of countless molecules that zoom around and bump into each other. They move faster when air is hotter. They move slower when air is colder. When you push the handle down, you squeeze the air into a smaller space. The plunger meets the molecules as they bounce off it. It is like a bat hitting a ball. It sends them away faster than they came.

Now the squeezed air has molecules with more energy. Its temperature goes up. The work of your arms has turned into heat. Some warmth also comes from the plunger rubbing inside the pump. Friction always makes a little heat.

The effect is small on a bike pump. It matters more in big machines. A diesel engine squeezes air so hard that it gets hot enough to ignite the fuel sprayed into it. No spark is needed. When squeezed air spreads out again, the opposite happens. It cools down.

▲ This passage · 215 words · Flesch-Kincaid grade 6.3

After you inflate a bicycle tire with a hand pump, touch the lower part of the pump. It feels warm. You did not plug it in or heat it, so where did the warmth come from? The answer shows how closely energy and heat are connected.

Air is a gas made of countless molecules zooming around and bumping into one another. They move faster when the air is hotter and slower when it is colder. When you push the pump handle down, you squeeze the air into a smaller space. The plunger meets the molecules as they bounce off it, and like a bat hitting a ball, it sends them away faster than they arrived.

As a result, the squeezed air has molecules with more energy, and its temperature goes up. The work your arms did has become heat. Part of the warmth also comes from the plunger rubbing against the inside of the pump, because friction always makes some heat.

The effect is small on a bicycle pump, but it matters in bigger machines. A diesel engine squeezes air so hard that the air becomes hot enough to ignite the fuel sprayed into it, with no spark needed. When squeezed air is allowed to spread out again, the opposite happens, and it cools down.

■ Harder · 246 words · Flesch-Kincaid grade 8.5

After you inflate a bicycle tire with a hand pump, touch the lower part of the pump, and you will probably find that it feels distinctly warm. You did not plug the pump into anything or hold it near a flame, so where did that warmth actually come from? The answer reveals just how closely energy and heat are connected to each other.

Air is a gas made of countless molecules that zoom around in every direction, constantly bumping into one another. They move faster when the air is hotter and more slowly when the air is colder. When you push the pump handle downward, you squeeze the air into a much smaller space. The plunger meets the molecules as they bounce off its surface, and, like a bat striking a ball, it sends them away faster than they arrived.

As a result, the squeezed air contains molecules with more energy, and its temperature rises. The work that your arms performed has been transformed into heat. Part of the warmth also comes from the plunger rubbing against the inside of the pump, since friction always produces some heat.

The effect is small on a bicycle pump, but it matters a great deal in larger machines. A diesel engine squeezes air so forcefully that the air becomes hot enough to ignite the fuel sprayed into it, with no spark required. When squeezed air is later allowed to spread out again, the opposite happens, and it cools down.

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 inflate, molecules, plunger, friction and temperature 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 Bicycle Pump Gets Warm as You Pump"?

It was written for 6th grade. It has 215 words and works out to a Flesch-Kincaid grade level of about 6.3. 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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