The Arizona STEM Acceleration Project

Longitudinal and Transverse Waves

Longitudinal and Transverse Waves

A 8th grade STEM lesson

Cassandra Cordts

July 25, 2023

Notes for teachers

• Groups of 2-4. Each group needs its own table.
• Go over how to treat slinkeys and be prepared to take them from groups that can not follow rules. I usually have between 25-50% loss of slinkeys during this lab to destructive behavior each year.
• Have a bin or container for slinkys to be placed in when not in use.
• Depending on the setup of tables in your classroom you may need to put a tape mid-line down on each table for students to use as a guide.

List of Materials

• Student slides
• Copy of slides for teacher
• Slinkeys with indicator (you can use colored masking tape or a foam ball that fits within the slinky)

AZ Standards

Core Ideas for Using Science:

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U1: Scientists explain phenomena using evidence obtained from observations and or scientific investigations. Evidence may lead to developing models and or theories to make sense of phenomena. As new evidence is discovered, models and theories can be revised.

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Physical Science Standards:

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8.P4U1.4 Develop and use mathematical models to explain wave characteristics and interactions.

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Mathematical Practices

1. Make sense of problems and persevere in solving them.

2. Reason abstractly and quantitatively.

3. Construct viable arguments and critique the reasoning of others.

4. Model with mathematics.

5. Use appropriate tools strategically.

6. Attend to precision.

7. Look for and make use of structure.

8. Look for and express regularity in repeated reasoning.

Objective:

Students will be able to define and identify compression/longitudinal and transverse waves and identify the key components in a wave.

Agenda

Objective: 1 minute

Agenda: 1 minutes

Introduction Activity: 5 minutes

Hands on Activity: 20 minutes

Connecting Observations: 20 minutes

Assessment: 5-10 minutes

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Intro/Driving Question/Opening

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Driving Question:

• What defines a wave?

Scaffolded Opening Questions:

• What cool stuff can you do with a slinky?
• What are some examples of waves in your own life/experience?

Intro/Frontloading

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• Explain: Waves can transmit energy in differing ways that allow the waves to travel very long distances. In this investigation you will examine two types of waves and how they travel. Today you are going to be using a spring to make different types of waves.
• Taking care of materials: Go over how we treat materials in the science classroom. Express that slinkys are cool but in class they are a tool not a toy. Ask how many students have messed up a slinky, how and what happened.

Hands-on Activity Instructions:

Compression Wave

• 2-4 students per group
• Give students roles in the activity; anchor, wave maker, flagger 1 and flagger 2.
• Go over instructions carefully with students.
• Utilize a timer to limit time and keep order.

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Make ONE Compression Wave

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1. The anchor holds one end of the spring in one spot on the table.
2. The wave-maker holds the other end of the spring and stretches it out about 1.5 meters long, flat along the center of the table.
3. One flagger attaches a piece of tape (or shoves foam ball in) about halfway down the spring. Flaggers stand on either side of the spring to observe.
4. Using a push-pull motion in the exact direction of the spring, the wave-maker sends a strong pulse down the length of the spring.
5. Record observations on the next slide of your investigation.

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Hands-on Activity Instructions:

Compression Wave

• 2-4 students per group
• Give students roles in the activity; anchor, wave maker, flagger 1 and flagger 2.
• Go over instructions carefully with students.
• Utilize a timer to limit time and keep order.

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Make a Series of Compression Waves

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1. The wave-maker repeats pulses rapidly in succession, counting as they go, “1-2-3… [up to] 10.” Flaggers follow along and make sure the count is accurate.
2. Rotate roles so that flaggers become the anchor and wave-maker. Everyone should have a chance to create waves and observe the behavior of the spring.
3. Record observations on the next slide of your investigation.

​

​

Hands-on Activity Instructions:

Compression Wave

• 2-4 students per group
• Give students roles in the activity; anchor, wave maker, flagger 1 and flagger 2.
• Go over instructions carefully with students.
• Utilize a timer to limit time and keep order.

​

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Make ONE Transverse Wave

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1. Anchor, wave maker, and flaggers set up the table (clearing it) and setting up the spring.
2. The wave- maker creates ONE wave using a side to side motion perpendicular to the spring.
3. The anchor keeps their side of the spring STILL.
4. Observe how the wave travels in to the anchor and returns.

Hands-on Activity Instructions:

Compression Wave

• 2-4 students per group
• Give students roles in the activity; anchor, wave maker, flagger 1 and flagger 2.
• Go over instructions carefully with students.
• Utilize a timer to limit time and keep order.

​

​

Make a Series of Transverse Waves

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1. The wave-maker repeats the side-to-side motion rapidly and evenly, counting as they go, “1-2-3… [up to] 10.” Flaggers follow along and make sure the count is accurate. Flaggers describe what they see.
2. Wave-maker repeats the activity speeding up (counting to ten) and then slowing down (from 11-20). Flaggers describe what they see.
3. Wave-maker tries to make a consistent wave (standing wave) where the crests and troughs always appear in the same position.
4. Record observations on the next slide of your investigation.

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Assessment

At this point in the unit student should be able to create a compression and a transverse wave as well as draw a simple model of each.

In my classroom I use a simple checklist to record that I have seen each student make each type of wave. At the end of class I check in with any student I have missed.

Student notebooks/observations are also a great formative assessment at this point.

It would be relatively easy to create a summative assessment. It would need to include examples of each type of wave and have students identify them and the opportunity for them to explain/define what a wave is.

Differentiation

Students who struggle manipulating the slinky can be given a piece of string.

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Integrating GIFs and models of this lab into later lessons to reinforce observations are helpful to students who struggle separating the types of waves.

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Having students use hand motions to mimic waves can help reinforce the shapes of each wave type.

Remediation

Extension/Enrichment

The next step in this learning goal is to determine the velocity of a wave.

An extension of this activity that addresses that next step is to create a standing wave and find the information needed to make those calculations. I often give this activity as an extension to students who are ready to move forward.

Student Work Slides

I use Google Slides to create a digital notebook with my students. Most days I use a copy of the same presentation that i have added animations and extra informational slides to if necessary. I have attached my student slides for this lesson to the slides that follow.

Investigation 1.2 Transverse Waves

Focus Question: What defines a wave?

What cool stuff can you do with a slinky?

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Type here…

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Directions: Insert & label 4 pictures of different kinds of waves below.

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Introduction: Waves can transmit energy in differing ways that allow the waves to travel very long distances. In this investigation you will examine two types of waves and how they travel. Today you are going to be using a spring to make different types of waves.

Wave

A back and forth pattern of motion that transfers energy

You have our science definition of a wave. Take a moment, discus what a wave is with your table. Then write the definition of a wave in YOUR OWN WORDS below.

Taking Care of Materials - Keeping our Springs Nice

1. The spring may look like a toy - in this room it is a science tool.
2. The spring is a delicate piece of science lab equipment that you are entrusted with.
3. Transport the spring in its box to and from the materials station.
4. At all times keep the spring entirely in contact with the table surface.
5. The spring should never be dangled or waved through the air.
6. If a spring accidentally becomes tangled, immediately call your teacher over to assess the situation.

Talk with a partner and decide what the word ‘compression’ means. Write your definition in your own words below:

Type here…

Compression Wave

Type here…

Make ONE Compression Wave

1. The anchor holds one end of the spring in one spot on the table.
2. The wave-maker holds the other end of the spring and stretches it out about 1.5 meters long, flat along the center of the table.
3. One flagger attaches a piece of tape (or shoves foam ball in) about halfway down the spring. Flaggers stand on either side of the spring to observe.
4. Using a push-pull motion in the exact direction of the spring, the wave-maker sends a strong pulse down the length of the spring.
5. Record observations on the next slide of your investigation.

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Reflect

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What happened to the masking-tape flag while the spring was moving?

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Where did the masking-tape flag end up when the wave stopped?

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When you made a single compression wave, what happened when the wave reached the end of the spring?

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Did the entire strength of the wave reflect?

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Make a Series of Compression Waves

1. The wave-maker repeats pulses rapidly in succession, counting as they go, “1-2-3… [up to] 10.” Flaggers follow along and make sure the count is accurate.
2. Rotate roles so that flaggers become the anchor and wave-maker. Everyone should have a chance to create waves and observe the behavior of the spring.
3. Record observations on the next slide of your investigation.

Kinetic energy

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Was there any reflection in the series of compression waves?

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What back and forth pattern of motion did you see with the series of compression waves?

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What energy did the compression wave transfer?

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The compression wave might not look like what you think of as atypical wave. As you will learn in this class, there are many types of waves. But all waves have two things in common: thye move in a back and forth pattern, and they transfer energy.

The energy of the wave transferred to your hand or the table, but the metal of the spring ended up where it started. Waves transfer energy, not matter. Energy of motion is kinetic energy. When you saw the metal of the spring moving, you were observing energy transfer.

Not all waves transfer kinetic energy. We will learn about waves that transfer other forms of energy. As we continue to explore waves, keep these two things in mind. Each time you see a wave, you should be able to identify a back and forth pattern of motion and a transfer of energy.

THE SPRING WILL BE TOUCHING THE TABLE AT ALL TIMES!!!!

Make ONE Transverse Wave

1. Anchor, wave maker, and flaggers set up the table (clearing it) and setting up the spring.
2. The wave- maker creates ONE wave using a side to side motion perpendicular to the spring.
3. The anchor keeps their side of the spring STILL.
4. Observe how the wave travels in to the anchor and returns.

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What did you observe when your group made the transverse wave?

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How was it different than the Longitudinal Wave?

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How was it similar to the Longitudinal Wave?

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THE SPRING WILL BE TOUCHING THE TABLE AT ALL TIMES!!!!

Make a Series of Transverse Waves

1. The wave-maker repeats the side-to-side motion rapidly and evenly, counting as they go, “1-2-3… [up to] 10.” Flaggers follow along and make sure the count is accurate. Flaggers describe what they see.
2. Wave-maker repeats the activity speeding up (counting to ten) and then slowing down (from 11-20). Flaggers describe what they see.
3. Wave-maker tries to make a consistent wave (standing wave) where the crests and troughs always appear in the same position.
4. Record observations on the next slide of your investigation.

What did you observe when your group made the transverse wave?

Type here…

What happened when the wave maker made the sid-to-side motion faster? What about when they made the motion slower?

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What were the challenges in creating a standing wave?

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Transverse Wave

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Transverse Wave

In a transverse wave, the wave moves at a right angle to (perpendicular to) the direction of the spring.

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