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Why Water Glasses Play Different Notes

4th grade nonfiction passage about pitch and vibration: 198 words, six questions, an answer key and vocabulary.

4th grade nonfiction pitch and vibration 198 words

Why Water Glasses Play Different Notes

Line up four glasses and pour a different amount of water into each. Now tap each glass gently with a spoon. You will hear four different notes. Why does the amount of water change the sound?

All sounds begin with vibrations, which are quick back-and-forth movements. When you tap a glass, the glass wiggles very fast, and the wiggling pushes on the air around it. The moving air carries the sound to your ears.

Pitch is how high or low a sound seems. It depends on how fast something vibrates. A fast vibration makes a high note. A slow vibration makes a low note.

Water is heavy compared with air. When a glass holds more water, the glass has more to move, so it vibrates more slowly. A glass with a lot of water makes a lower note. A glass with only a little water vibrates faster and makes a higher note.

Musicians use a similar idea. A long guitar string vibrates slowly and makes a low sound, while a short string makes a high one. Be careful when you try this at home. Use plastic or sturdy glasses, and ask a grown-up to help.

Questions

  1. What do all sounds begin with? in the text

  2. What does the wiggling glass push on to make sound reach your ears? in the text

  3. What is pitch? in the text

  4. Which glass makes a lower note, the one with more water or the one with less? in the text

  5. Why does a glass with more water vibrate more slowly? think about it

  6. What kind of guitar string makes a high sound? in the text

Words to know

vibrations
very fast back-and-forth movements
pitch
how high or low a sound is
gently
in a soft, careful way
sturdy
strong and not easy to break
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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 · 162 words · Flesch-Kincaid grade 1.8

Line up four glasses. Put a different amount of water in each. Tap each glass with a spoon. You hear four different notes. Why does the water change the sound?

All sounds start with vibrations. A vibration is a fast back-and-forth move. When you tap a glass, the glass wiggles fast. The wiggle pushes on the air. The moving air takes the sound to your ears.

Pitch is how high or low a sound is. It depends on how fast something vibrates. A fast vibration is a high note. A slow vibration is a low note.

Water is heavy. A glass with more water has more to move. So it vibrates slower. It makes a lower note. A glass with a little water vibrates faster. It makes a higher note.

A long guitar string vibrates slowly. It makes a low sound. A short string makes a high one. Try this with plastic glasses and ask a grown-up to help.

▲ This passage · 198 words · Flesch-Kincaid grade 3.9

Line up four glasses and pour a different amount of water into each. Now tap each glass gently with a spoon. You will hear four different notes. Why does the amount of water change the sound?

All sounds begin with vibrations, which are quick back-and-forth movements. When you tap a glass, the glass wiggles very fast, and the wiggling pushes on the air around it. The moving air carries the sound to your ears.

Pitch is how high or low a sound seems. It depends on how fast something vibrates. A fast vibration makes a high note. A slow vibration makes a low note.

Water is heavy compared with air. When a glass holds more water, the glass has more to move, so it vibrates more slowly. A glass with a lot of water makes a lower note. A glass with only a little water vibrates faster and makes a higher note.

Musicians use a similar idea. A long guitar string vibrates slowly and makes a low sound, while a short string makes a high one. Be careful when you try this at home. Use plastic or sturdy glasses, and ask a grown-up to help.

■ Harder · 204 words · Flesch-Kincaid grade 6.9

Arrange four glasses in a row and pour a different quantity of water into each one. Now tap every glass lightly with a spoon, and you will hear four distinct notes. Why should the amount of water alter the sound so noticeably?

All sounds originate from vibrations, which are rapid back-and-forth movements. When you tap a glass, the glass wiggles extremely quickly, and that wiggling pushes against the surrounding air. The moving air then carries the sound to your ears.

Pitch describes how high or low a sound seems, and it depends on how quickly something vibrates. A fast vibration produces a high note, whereas a slow vibration produces a low note.

Water is quite heavy compared with air. When a glass contains more water, there is more material for the glass to move, so it vibrates more slowly and makes a lower note. A glass holding only a little water vibrates faster and makes a higher note.

Musicians rely on a similar principle. A long guitar string vibrates slowly and gives a low sound, while a short string gives a high one. Use plastic or sturdy glasses if you try this at home, and ask a grown-up to help you.

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 vibrations, pitch, gently and sturdy 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 Water Glasses Play Different Notes"?

It was written for 4th grade. It has 198 words and works out to a Flesch-Kincaid grade level of about 3.9. 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. 5 ask for something the text says directly and 1 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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