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Waves of Sound Unit Share
Mystery 1 of 3
How far can a whisper travel?
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DISCUSS (1 of 2): Put your hand over your throat and make some sound. What do you notice?

DISCUSS (2 of 2): What do you think sound is?

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DISCUSS: What kind of experiments could we do to figure out more about what sound is?

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Beginning Complete!

You've completed the Exploration & Activity!

If you have more time, view the assessment, reading, and extension activity in the extensions.

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Extensions

Below are ideas for extending this topic beyond the activity & exploration you just completed.
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Activity: Secret Bells

If you need to be convinced that sound can actually travel through a string, try this activity from San Francisco’s Exploratorium. With a string and a spoon, you can make amazing music that only you can hear.

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Activity: Going around corners

Suppose you have a paper cup telephone that’s working great in the hall, where the string is straight. Then your friend ducks into a room and the string has to go around a corner. The phone stops working!

Can you figure out how to get it working again? This is a tough engineering challenge. Think about what changes when you go around a corner. What might be stopping the vibrations from traveling down the string?

If you want to see solutions that other people have come up with, check this site.

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Discussion/Activity -- Paper cup telegraph

Suppose you keep making the string on your paper cup telephone longer and longer. At some distance, you can hear your friend talking — but you can’t tell what they are saying.

Can you think of a way to send a message when your friend can hear you, but can’t understand the words? Can you use a pattern of sounds to send a message without words?

If you’d like to see our ideas on how to do this, you’ll find them here.

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Paper cup telegraph — Our Ideas

We gave one idea away in the title! The telegraph invented by Samuel Morse uses Morse code to communicate with two sounds — dots and dashes. Can you make two sounds that your friend can tell apart through the long string? If you can, you can communicate with Morse code. Learn more about Morse code here.

Here’s another idea. You can communicate using a tap code, like this one. Using this code, a pattern of taps can be translated into letters.

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Readings:

You acted like an engineer when you experimented with a paper cup telephone. These Common-Core-aligned readings about engineering are free with registration on ReadWorks. All include comprehension questions.

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Image & Video Credits

Mystery Science respects the intellectual property rights of the owners of visual assets. We make every effort to use images and videos under appropriate licenses from the owner or by reaching out to the owner to get explicit permission. If you are the owner of a visual and believe we are using it without permission, please contact us—we will reply promptly and make things right.

Exploration
unit: siblings whispering by wong sze yuen
echo "hello" by © Jojikiba , used under CC BY-SA
graffiti tunnel by jmiller291 , used under CC BY-SA
"awesome echo" by Emma Koi
boy yelling in forest by Zurijeta
Zac by Ric Moxley
grand canyon at sunrise by sumikophoto
Zac's echo in the grand canyon by Ric Moxley
group of friends by aslysun
two people whispering by sezer66
slo mo drum by The Chernett Family
Speaker Vibrations affect Objects by BluePigProductions: Eric van der Aar
cups vibrating from speakers by ReggieErf
Activity
graphic pencil by JohannPoufPouf , used under Public Domain
kitten by Okssi
seagull by CocoParisienne , used under Public Domain
two differently sized cups by Maistrenko Ihor
Overview
Grade 4th
Topic Sound, Waves, & Communication
Focus Sound, Vibration, & Engineering
Print Prep
Activity Prep

In this Mystery, students learn about the connection between sounds and vibration. In the activity, Paper Cup Telephone, students make telephones using cups and string. Students then modify the design of their telephones using different types of supplies to see if they can improve the sound quality.

Preview activity

Number of students:
Engineering Materials
Students will experiment with different materials for their paper cup telephones. They will need more paper clips and additional items, such as construction paper, different sized cups, yarn, ribbon, or dental floss.
Details
60 items
Pencil
30 pencils
Coated Paper Clips (#2)
We recommend coated, because they are stronger. You can use any paper clip that is about 1" long, not jumbo paper clips.
Details
30 clips
Paper Cups (8 oz)
30 cups
Thin String
180 feet
Paper Cup Telephone printout Print 30 copies
Paper Cup Telephone Answer Key printout Print 1 copy
Paper Cup Telephone Teacher Tips printout Print 1 copy
Prep Instructions

Each student will first make half of a paper cup telephone. Then, students will pair up to complete their telephones. Homeschool students will need a partner for the activity.

Students will also have the chance to come up with their own experiments with the telephone. The list below shows materials they could use. You can get more materials if you'd like.

  • more paper cups, including larger and smaller cups
  • construction paper that could be used to make a cup larger
  • ribbon, yarn, dental floss, or other kinds of string
  • more of the same string you used before
  • more paper clips

Prepare String

Each student needs a piece of string that is 6 feet in length. Read our Teacher Tips for an easy way to prepare several strings all at once using a yardstick.

Display Engineering Materials

Your students will have the chance to come up with their own experiments with the phone. But before students attempt to modify and improve the design of their telephones, they need to know which materials are available to them. During Step 15 of the experiment, we suggest you show students which of these will be available.

Overview
Grade 4th
Topic Sound, Waves, & Communication
Focus Sound, Vibration, & Engineering
Extensions