The Arizona STEM Acceleration Project

Sound Waves 3: Sound Travel

How does sound travel from the source of vibrations to our ears?

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An 8th grade STEM lesson

Jamie Rapkiewcz, M.Ed.

5/10

Notes for teachers

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• Intro to sound waves lesson and initial Model of sound waves, in classroom 1-2 hours depending on student uncertainties
• Students may work in small groups of 2-4.
• Students should do this lesson after doing Peggy Lord’s Sound Lessons 1 and 2 that explored sound waves with beakers and water.
• This lessons helps students understand that it is not the particles of air themselves that travel, but the energy through wave that is causing particles to vibrate.

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List of Materials

• Phet Simulation: https://phetsim-waves-intro.netlify.app/?scrlybrkr=636dca8e
• Student Worksheet (pre-assessment and formative assessment included)
• Model Explanation for TEACHERS
• Exit Ticket idea for Notebook
• Optional for demonstration you can use tuning forks to make vibrations visible, this can be used as an analogous phenomenon for discussion.

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Additional Teacher Tips:

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There is a lot to "unpack" following the Phet simulation. In the class discussion here, be sure to provide time for students to discuss and reach consensus about:

• The movement the speaker makes to produce sound
• The role particles play in sound
• How a sound wave moves
• How particles change as a sound wave moves through them

You may ask students in groups to create an initial model to explain their thinking about each of these bullets. Students can then speak to their models as they share their explanations.

8th Science Standards

8.P4U1.4

Develop and use mathematical models to explain wave characteristics and interactions.

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Science and Engineering Practices

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• ask questions and define problems
• develop and use models
• plan and carry out investigations
• analyze and interpret data
• use mathematical and computational thinking
• construct explanations and design solutions
• engage in argument from evidence
• obtain, evaluate and communicate information

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8th Math Standards

8.F.B

Use functions to model relationships between quantities.

Objective(s):

Lesson Question: How does sound travel from the source of vibrations to our ears?

Big Science Ideas:

• Sound is the vibration of air particles, which is different from the movement of air, like wind.
• The vibration of air particles can vibrate other objects, like hair, the membrane in our ear, or the membrane of a microphone.

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Success Criteria: I can model and describe how sound waves are produced and how they travel through a medium such as air.

Agenda (lesson time)

Day 1

Phenomena 8 minutes

Initial model 6 minutes

Phet simulation 8 minutes

Class Discussion 10 minutes

Final model and gallery walk 15 minutes

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Intro/Driving Question/Opening

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Lesson 3

-Explore a Phenomenon:

Is it possible for sound to cause someone’s hair to move?

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Write your prediction in your notebook.

Video: https://youtu.be/ikcoiALcucg

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What would the space between the speaker and your ear look like?

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The electrical signal from the car’s stereo

The car’s speakers

Air

What is going on in this space?

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How can sound cross distances?

How can sound move things?

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Write your thoughts in your science notebook so you are ready to contribute to the class explanation.

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Initial Model: Complete your initial model about how sound travels from a mouth to another person’s ear

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Things to consider with your model

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• What is causing the sound?
• Are the air particles moving? If so, what is causing them to move?
• How is the sound getting into the ear?
• What is causing our ears to hear the sound?
• What is our ear doing when we hear the sound?

Try This!

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1. Hold the piece of paper half an inch in front of your lips again.
2. Sing a note into it. Be loud!
3. What do you feel in your fingers?

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Now try this!

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1. Hold a piece of paper half an inch in front of your face.
2. Blow on it.
3. What do you feel in your fingers?

How did blowing and singing into the paper help explain what is happening in the air? Share your thinking with your shoulder partner

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The electrical signal from the car’s stereo

The car’s speakers

Air

What is going on in this space?

To visualize how the air is moving we will use a simulation that allows you to see the air particles.

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The electrical signal from the car’s stereo

The car’s speakers

Air

Open your computers and navigate to the Phet Simulation, but don’t explore the app quite yet.

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Phet Online Simulation

These circles represent particles of air.

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Before you get started…

EXPLORE

Don’t click the speaker button yet…

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…watch the air particles.

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Before you get started…

EXPLORE

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How are the air particles moving?

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Be prepared to share your thoughts and ideas in the whole class discussion.

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In a small group, discuss the questions below. Decide ahead of time who will represent your group as you share out.

With your A/B partner, compare your models. Explain your model and ask about theirs.

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Is there anything you should add or change in your models to make them more clear or accurate?

• Click the speaker button to make it move!

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• Try both single pulse and continuous pulse

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• Click to Play or Pause

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Next, let’s use the simulator to visualize how sound move through the air.

As you produce sound, watch the speaker and watch how all the particles interact.

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1. How is the speaker moving to produce sound?
2. Look at a single particle. How is it moving?
3. How are all the air particles moving?
4. What causes the pattern of movement that you see?

With your group, discuss the following questions about sound production. Decide ahead of time who will share your groups ideas with the class.

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I observed _____ which makes me think____.

________causes ________ because________.

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With your A/B partner, compare your models. Explain your model and ask about theirs.

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Is there anything you should add or change in your models to make them more clear or accurate?

Assessment

Formative:

1. Look at initial models and final models to see student thinking and depth of understanding.

2.Listen for student ideas and uncertainties that are shared when students are discussing models and group questions.

3. Check final models for revised thinking and ideas.

Summative:

Exit Ticket: What would happen if there were no air molecules?

Exit Ticket

What would happen if there were no air particles?

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Choose one of the following to expand on:

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• Write a description of what changes between a low frequency and high frequency sound.
• Write a description of what changes between a low and high amplitude sound.
• Write a description about what happens during the production of a sound.

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Differentiation

-have students look at how energy travels using a Newton’s cradle.

-Ask students questions that challenge their thinking for example, if it is the actual particle of air that moves into your ear, explain how someone standing behind the speaker can hear at the same time as someone in front of the speaker.

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Remediation

Extension/Enrichment

• Have students elaborate on the model by thinking of other phenomena show how energy travels through a wave, like a rock in a pond.