Musical Instruments part 2

developed by W.K. Adams

Students experiment with various sound sources, including their voice, cup instruments, string, and guitars, to gain an understanding of the connection between sound and vibration. This lesson is designed for uses AFTER the Sound and Music introductory lesson and Musical Lessons Part 1.

Grade Level

6-12

Clean-Up

5 minutes

Learning Goals

Students will be able to:

• describe how string instruments require a source of vibration and a way to change pitch/resonance and use sympathetic vibration to amplify sound.
• define frequency and vibration in terms of a sound wave and what we hear.
• understand that vocalizing and music both require a source of sound – vibrations – a way to change pitch resonance and a way to amplify sound.

Materials not in Kit

Scissors – 1 per group
5 foot piece of string — 1 per pair
Cup Instrument — 1 per pair
Plastic Cup — 3 different types (varying sizes/material) divided among the groups
String — two different kinds, divided randomly amongst the groups, One smooth/shiny and one rough cotton/twine make good comparisons
Big paperclip
Wet paper towels – 1 or 2 per group
Acoustic Guitar**
Electric Guitar**

*Students can use the straw instrument they built for the introductory Music and Sound lesson, or you can gather materials to make new ones.
**Guitars can often be easily accessed by teachers. Try asking the music department in your school or local music stores. Most are perfectly happy to lend instruments for learning experiences.

Advanced Preparation

Complete the Sound and Music introductory lesson and the Musical Instruments Part I lesson.
Gather supplies (see materials list).

Set-Up

Set up the guitars in one area of the room and then prepare stations for each group of students with each of the following:

• A 3 foot piece of string
• Plastic cups (1 per pair)
• String (1 piece per pair)
• Paper clip (1 per pair)
• Scissors
• Paper towels

Introduce the Activity

Explain that all the required materials for the lesson are together before the students divide into groups for the activity.

Tell the class they will be exploring musical instruments by using their voice, a string, and a cup instrument.

Begin the lesson by introducing the idea of a voice being a musical instrument. Ask the students questions about their voice, such as:

• How can we feel the movement made by our voices? If the students struggle to find an answer to this question, ask a leading question such as: Where on our bodies can we feel our voices vibrating?

Students should experiment with this idea for a short period of time. Have the students hold their fingers against the front of their throat and say Aaaaah, and to notice the vibration against their fingers.

Hand out a packet to each student.

Doing the Activity: Your Voice

Your Voice
Students will work together in small groups to try out different sounds with their voice, including Aaaah, Ooooh, Eeeee, Ssss, and Ffffff. They will hold their hands to their throats while speaking, and answer questions 1-5 in their packet.

Explain that pitch varies with the emphasis given to different words. The last words of a question, for example is at a higher pitch.

Doing the Activity: String Activity

The students will tie a five-foot piece of string to a table leg, pull it tight, and pluck it. After plucking the string they try sliding the string between their thumb and index fingers. They will answer questions 6-7 in their group.

Doing the Activity: Cup Instrument

Students will create a cup instrument by:

1. Poking a hole in the bottom of the cup carefully with scissors
2. Threading the string through the hole
3. Attaching the paper clip to the string inside the cup
4. Pulling the extra string out of the cup so the paper clip is on the bottom of the cup

As the students work, walk around the room to assist as needed.

Students will hold the cup so the string is loose and slide the string between their thumb and index finger, then answer questions 8-9. With the cup attached this whispering will be nicely audible.

Students will attach the string of the cup instrument to a table leg. They will pull the cup so that the string pulls tightly against the table leg, and pluck the string. One partner holds the string at different lengths from the cup while the other plucks it (still tied to the table leg). Students will work through questions 10-15.

Students will wet their paper towels and pinch the string very tightly as they slide the towel down the string. If they do it correctly, they’ll get a horribly loud obnoxious screeching sound. They will answer questions 16-17.

Doing the Activity: Electric vs. Acoustic Guitars

The students will compare the two types of guitars. Pluck a string on each one and compare the sounds, answering questions 18-21.

Doing the Activity: Compare Cup Instruments

Students will find at least two other groups that used different cups but the same string and compare and contrast the two on question 22.

Students will find another group that used the same cup but different string, then answer questions 23-24

The students will try to make a chicken sound (quick short slides) and a whale sound (long smooth slides) with the cup instruments.

Explanation

The cup instrument’s source of sound is plucking the string which creates vibrations. The pitch is determined by the length of string. The string “resonates” at a particular frequency depending on its length. The cup itself amplifies the sound via “sympathetic vibration”. Electric guitars do not have a hollow body so there is nothing to amplify the sound. This is why they require an electric amplifier.

Key Lesson Terminology

Sound wave – Vibrations of air molecules that travel through air carrying energy with them.

Vibrations – a shaking back and forth movement

Resonance – A natural frequency of vibration determined by the size and shape of an object

Frequency (rate) – wiggles per second (moves back and forth)

Sympathetic vibration – When a vibrating object is put in contact with another material and makes it vibrate. This is a transfer of energy and is how an acoustic guitar (not electric guitars) amplifies sound. The strings cause the body to vibrate and the body vibrates via sympathetic vibration, which moves more air than the strings alone so it’s louder.

Resonance Chamber – uses resonance to amplify sound

Pitch – how high or low a tone sounds to a person. High frequency sound has a high pitch or tone (treble notes), but low frequency has a low/deep pitch or tone (bass notes). High sounds are usually above 2000 Hertz and low below 200 Hertz.

Modifications

Hard of hearing students can feel vibrations through speakers by touching them, or by touching the instrument itself.

Optional Extensions

• Students could add to a vocabulary sheet.
• Students can complete the How Musical Instruments Work activity – this activity has been necessary in my experience to really generalize how instruments work and to work on the idea of sympathetic vibration vs. resonance.
• Students who play a stringed instrument can bring their instrument to class to show how their homemade instruments compare to more commonly used and played instruments.