Hands-on Activity Make Some Waves

Learning Objectives

After this activity, students should be able to:

• Explain what a longitudinal wave is and give an example.
• Explain what a transverse wave is and give an example.
• Create plots of sin and cosine wave functions (if using extension activity)

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

NGSS: Next Generation Science Standards - Science

International Technology and Engineering Educators Association - Technology

State Standards

Materials List

For each group:

• 2 copies of the Wave Worksheet
• 1 Slinky® (groups may share if there are not enough Slinkys®
• 2 meter long length of rope (about the thickness of a clothesline)
• 10 Dominoes®

Worksheets and Attachments

Introduction/Motivation

Do you all remember what we learned about the two different types of waves? Can anyone tell me what the two types are? Super! Now can someone explain what a longitudinal wave is? Great — and how about the other wave, transverse? Who can explain how that one moves? Fabulous! And can someone give me an example of a transverse wave? How about a longitudinal wave? Terrific! Now that we have learned about the two types of waves, we are going to make some ourselves using Slinkys®. I have one more question for you — who can tell me why an engineer would need to know about waves? Well, we are going to talk more about this later on, but sound and light travel in waves, so engineers can use what they know about sound waves and light waves to build radios, televisions, light bulbs and even reading glasses. Engineers use what they have learned about waves to help people in many different ways.

Procedure

The key points to convey to the students are that a wave is a moving disturbance through a medium and that longitudinal and transverse waves move in different ways. Longitudinal waves oscillate in the same direction that they travel, while longitudinal waves oscillate in a direction perpendicular to their motion.

Before the Activity

• Gather all necessary materials.
• Make copies of the Wave Worksheet (one per student).

With the Students

Class Demonstration

1. Have the students form a circle with their right shoulders pointing towards the center.
2. Ask students to design a way for this ring of students to create a transverse wave. An idea should come up where a student raises her arms and then lowers them, and then the student behind her raises her arms and lowers them, and so on around the circle. It should be like the "wave" in a football stadium.
3. After the students have the hang of it, ask them what the disturbance in the wave was. (Answer: Their raised, then lowered, arms were the disturbance.)
4. Ask them if the disturbance travels up and down or horizontally around the circle. (Answer: up and down)
5. Ask them if the wave traveled horizontally around the circle or up and down. (Answer: around the circle) The disturbance oscillating perpendicular to the direction the wave travels is the definition of a transverse wave.
6. Still standing as in Demo #1, ask the students to describe which direction the disturbance would travel in the ring if the students wanted to make a longitudinal wave. The students should say that the disturbance needs to travel in the same direction as the wave, and around the ring.
7. Ask students how can they make a longitudinal wave? Have one student gently push the back of the student in front of her, and then the pushed student should gently push the student in front of her and so on, this will make a longitudinal wave traveling around the ring.
8. Ask students: What is the disturbance? (Answer: the push) Is the disturbance traveling up and down or around the ring? (Answer: around the ring) Which way does the wave travel? (Answer: around the ring) Because this disturbance travels in the same direction as the wave, it is a longitudinal wave.

Student/Team Demonstration

1. Break students into groups of 2.
2. Give each group a Slinky®, rope and 10 Dominoes®.
3. Ask them to work with their partner to create longitudinal and transverse waves using all of these items. Most likely they will be able to create both longitudinal and transverse waves with the Slinkys®, but only transverse waves with the rope and longitudinal waves with the dominoes. (Note: Be sure to give the students plenty of time and room to experiment on their own.)
4. Instruct students to complete the Wave Worksheet.

Vocabulary/Definitions

longitudinal wave: A wave whose particles oscillate in the same direction as the wave travels.

oscillate: To vibrate back and forth.

transverse wave: A wave whose particles oscillate perpendicular to the direction that the wave travels.

wave: A traveling disturbance in a medium.

Assessment

Pre-Activity Assessment

Class Review: Briefly review the different types of waves with the students before starting the activity.

Activity Embedded Assessment

Group Discussion: While the class is gathered in a circle, be sure to ask for student input before creating the different types of waves together. If you like, give students time to turn to the person next to them and come up with an idea for creating the wave. This encourages independent creative thinking, without letting the teacher give all the answers right away.

Post-Activity Assessment

Wave Worksheet: With 10 minutes left in class, ask students to complete the Wave Worksheet.

Patterns: Using their observationsa asks students to discuss patterns that can be used to predict future motion.

Share With the Class!: Invite students to share with the class how they used the materials to create the different types of waves. Encourage them (as time allows) to demonstrate their methods to the rest of the class. Make sure they explain which type of wave they are demonstrating.

Safety Issues

During the Class Demonstration, ensure that students do not push each other hard, as a student could hit their head on the other student's back.

Remind students not to roughhouse or hurt each other when using the ropes and Slinkys®.

Activity Extensions

Students can conduct the "Slinky in Hand: Making Waves" activity from the Exploratorium Snacks website at: http://www.exploratorium.edu/snacks/slinkyinhand/index.html.

Student may visit http://www.acs.psu.edu/drussell/Demos.html for excellent animations of longitudinal and transverse wave behavior.

Activity Scaling

For upper grades, have students use Excel® to create plots of sin and cosine wave functions. For lower grades, do activity as is.

References

Copyright

Contributors

Supporting Program

Acknowledgements

The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education, and National Science Foundation GK-12 grant no 0338326. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.