Lesson Sounds Like Music

Learning Objectives

After this lesson, students should be able to:

• Explain that sound is a form of energy.
• Explain the relationships between pitch, frequency and wavelength (as frequency increases, pitch increases, and as wavelength increases, pitch decreases).
• List different media through which sound waves can travel.
• Explain that music is the organization of sound.

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

Common Core State Standards - Math

International Technology and Engineering Educators Association - Technology

State Standards

Worksheets and Attachments

Introduction/Motivation

(The most entertaining way to introduce the lesson is to provide some sort of musical performance—perhaps a concert recording listened to through a compact disc player, a short video of a musical performance, or maybe the teacher playing an instrument. Some useful materials to have handy to show and talk about during the lesson include glass bottles with water, tuning forks, and some sort of stringed instrument, such as a guitar or violin.)

What is the difference between sound and music? (Play an example musical performance. Then listen to student answers to the question.)

(Demonstrate the tuning fork to illustrate sound transmission. Hit the fork with the hand, generating a tone. Then, by touching the vibrating fork to something wooden and hollowed out, the air inside the wood vibrates and the pitch generated by the tuning fork is greatly magnified.) Why does the sound get louder? (Get students to speculate.)

How do you think stringed instruments change pitch? (Bring out a few glass bottles and with varying amounts of water in them. Blow across the tops of the bottles, making different sounds.) Why do these bottles make different sounds? (Gradually fill a bottle while blowing across the top so that higher pitches are generated. Next, experiment with stringed instruments, getting them to generate different pitches. Continue to present students with the content in the Teacher Background section.) Following the lesson students can apply their learnings with the fun and hands-on associated activity Strum Along with Shoebox Stringed Instruments: Sound or Music?

Lesson Background and Concepts for Teachers

Understanding something audible that is clearly music and then separating it into individual sounds is the goal of the lesson. Further, this lesson will help define and elaborate on the connections between sound and music.

Sound exists everywhere in the world. Typically objects cause waves of pressure in the air, which are perceived by people as sound. When an object is struck, it can vibrate with a certain frequency. The particular sound the object makes when struck is a direct result of the frequency at which it vibrates. A good example is hitting a glass bottle that has water in it.

Among the sounds that exist in everyday life, a few produce a definite pitch, such as blowing air over half-full glass bottles, tapping a glass with a spoon, and tapping long steel rods against a hard surface. This is because a certain component of the object vibrates in a periodic fashion.

Certain things can affect the frequency at which an object vibrates. With a guitar string, the string tension, thickness and length all affect the frequency. Anything that makes the object vibrate faster increases the frequency and thus increases the pitch that an object produces. Thus, the pitch produced by an object can be changed by the length or the volume of the portion that vibrates. For example, by gradually filling a bottle while blowing across the top, higher pitches can be generated. By organizing a few of these sounds with a clearer pitch, the sounds become closer to music.

When these vibrations are graphed, the result is something of a "squiggly" wave, also known as a sinusoid. The peaks are called crests, the valleys are called troughs, and the wavelength is the distance from one point on one cycle of a wave to the corresponding point on another cycle of the wave. Wavelength is inversely proportional to frequency. As a wavelength gets bigger, the lower the frequency (and fewer vibrations per unit of time) at which the object vibrates. Thus, the sounds caused by objects can be somewhat controlled. In the case of a stringed instrument, the sound can be very carefully controlled.

The very first musical instruments involved using various objects (such as bells) that have different pitches, played in sequence. These sounds with particular vibrations can be organized and played in a pleasing order to make music. The water-filled glass bottles provide evidence of this as simple songs can be learned on the bottles. This method of sound manipulation is the basis for many instruments, which demonstrates how sound and music correlate.

Since the first instruments, the ability to control pitch has greatly improved as illustrated by more modern instruments such as guitars, violins, pianos and more. Music is comprised of organized sound, which is made of specific frequencies. The organization of the pitches is what transforms sounds into music.

Ask the students if they think loudness is related to this lesson? Does wavelength, frequency, or amplitude affect this? (Answer: Amplitude). Ask the students if they have heard of an amplifier? This increases the amplitude of a wave (eg. sound waves from a guitar) to give the wave more ENERGY and VOLUME.

Ask the students if they have ever been to the beach? Do you think that big waves carry more energy than small waves? (Answer: Yes!). This is an example of amplitude in action. A taller wave (tsunami) carries much more energy than a smaller wave. Bigger wave = more amplitude = more energy!

Associated Activities

• Strum Along with Shoebox Stringed Instruments: Sound or Music? - Students apply the concepts of the lesson to simple stringed instruments they make from rubber bands and boxes. Then the class organizes its sounds into music.

  Watch this activity on YouTube

Lesson Closure

How is sound different from music?

One way to demonstrate this is to make a simple recording on a cassette or a compact disc of various sounds as well as clips of music and have students vote on which audio clips are sound and which audio clips are music. (Answer: Opinions vary—it is subjective—but most agree that music is organized sounds.)

How can we control what frequency an object vibrates at?

The shortening of what vibrates (such as string) leads to a higher pitch. In the case of glass bottles, since the column of air inside is what vibrates, shortening the column (adding water) makes the sound produced by blowing across the top higher in pitch.

How can we change the loudness of something?

By increasing a wave's amplitude, or how much energy it has, the volume increases. It takes a lot of electricity to run a concert, because the sound waves need to be enlarged so much!

How do we know that sound can travel through different media?

A tuning fork provides a good example of this fact. Additionally, comparing any stringed instrument to just a piece of string shows this fact because a string by itself does not produce much sound; thus, the string transfers the sound to the body of the stringed instrument, which then vibrates, causing the air to vibrate and make sound. We also know that sound can also travel through water, for example, whales communicate using sound.

Vocabulary/Definitions

amplitude: How large a wave is, from top to bottom.

frequency: The number of complete cycles of a periodic process occurring per unit time.

music: Organized sounds.

sound: Vibrations transmitted through a medium, with frequencies in the range capable of being heard by humans.

vibration: A rapid motion of a particle or solid about a central position.

wavelength: In a series of waves, the distance between two consecutive "peaks" or between two consecutive "valleys."

Assessment

If students are able to use the example with glass bottles filled with liquid and propose a rule for how the sound made by the bottle changes (more water = higher pitch), then they understand one of the main goals. The same goes for a stringed instrument.

Successful completion of the associated activity, Strum Along, also demonstrates an understanding of the lesson principles.

Have students complete the Sounds Like Music Worksheet.

Copyright

Contributors

Supporting Program

Acknowledgements

This content was developed by the MUSIC (Math Understanding through Science Integrated with Curriculum) Program in the Pratt School of Engineering at Duke University under National Science Foundation GK-12 grant no. DGE 0338262. However, these contents do not necessarily represent the policies of the NSF, and you should not assume endorsement by the federal government.