Lesson plan

Topicm20ee5edb7875a29f_1528449000663_0Topic

Mechanism of sound creation with musical instruments

Levelm20ee5edb7875a29f_1528449084556_0Level

Second

Core curriculumm20ee5edb7875a29f_1528449076687_0Core curriculum

VIII. Vibrating motion and waves. The student:

9b) demonstrates sounds of different frequencies using a vibrating object or a musical instrumentmusical instrumentmusical instrument.

Timingm20ee5edb7875a29f_1528449068082_0Timing

45 minutes

General learning objectivesm20ee5edb7875a29f_1528449523725_0General learning objectives

Explaining the rules of making sounds with musical instruments.

Key competencesm20ee5edb7875a29f_1528449552113_0Key competences

1. Explaining the role of the standing wavestanding wavestanding wave phenomenon in the creation of sounds with musical instruments.

2. Presentating harmonic waves generated in various instruments.

3. Determining the frequency of sounds generated with musical instruments.

Operational (detailed) goalsm20ee5edb7875a29f_1528450430307_0Operational (detailed) goals

The student:

- the rules of making sounds with musical instruments,

- to determine the frequency of sounds generated with musical instruments.

Methodsm20ee5edb7875a29f_1528449534267_0Methods

1. Flipped classroom.

2. Formulating problems and ideas for solving them.

Forms of workm20ee5edb7875a29f_1528449514617_0Forms of work

1. Student’s own work with the book and the Internet.

2. Working in groups to solve problems.

Lesson stages

Introductionm20ee5edb7875a29f_1528450127855_0Introduction

Answer the introductory questions:

1. What is the wave interference?
2. What conditions must be met to create a standing wavestanding wavestanding wave?
3. What are the nodes and the antinodes of a standing wave?
4. What are the harmonic waves of a standing wave?

Procedurem20ee5edb7875a29f_1528446435040_0Procedure

1. What is a musical instrumentmusical instrumentmusical instrument?

A musical instrument is any object that produces sound, and this sound is used to create music.

2. What can be the source of sound in musical instruments?

Because the vibrating bodies are the source of sounds, the essential element of every musical instrument must be the body that vibrates with the right frequency. This body can be a stringstringstring in stringed instruments or a column of air in brass instrumentsbrass instrumentsbrass instruments, a membrane of loudspeaker or drum, a resilient piece of metal in music boxes or cymbals, etc.

3. Classify musical instruments according to the way the sound is created.

Various classifications and systematics of musical instruments are introduced in science. In this lesson, we limit the description to two popular types of instruments, i.e. stringstringstring and brass instrumentsbrass instrumentsbrass instruments.

The standing wavestanding wavestanding wave can be created in vibrating strings as well as an air column (so‑called pipes).

The following types of fifes can be distinguished:

- open on both ends,
- closed on both ends,
- closed on one ends.

4. Present standing waves which are created in stringed instruments.

[Illustration 1]

If a string of, e.g. guitar, is the source of the sound, then the instrument is a stringed instrument.

In places where the string is attached, the nodes of the wave are formed.

Possible sample shapes of standing waves in a tight string with length L.

[Illustration 2]

5. What is the fundamental frequency of a vibrating string, rigidly attached on both ends?

[Illustration 3]

The length of the transverse wave on the stringstringstring is not equal to the length of the sound wave due to the differences in the propagation velocities of both waves in both media.

6. Present in the graphs the share of individual harmonic components in creating the timbre of the sound.

[Illustration 4]

[Illustration 5]

When a vibrating column of air is the source of sound, then we talk about fifes. Depending on the construction of the instrument, fifes can be closed on both ends, open on both ends or semi‑open.
In the place when the fife is closed, the nodes of the standing wave are formed, while their antinodes appear at the open ends!
Frequency of vibrations of air column in fifes.m20ee5edb7875a29f_1527752256679_0When a vibrating column of air is the source of sound, then we talk about fifes. Depending on the construction of the instrument, fifes can be closed on both ends, open on both ends or semi‑open.
In the place when the fife is closed, the nodes of the standing wave are formed, while their antinodes appear at the open ends!
Frequency of vibrations of air column in fifes.

7. Present the standing waves which occur in the fifefifefife which is open on both ends.

The fife is open on both ends.

[Illustration 6]

8. What is the fundamental frequency of a vibrating air column in the fife open at both ends?

The situation is analogous to that of a tight stringstringstring attached on both ends!

[Illustration 7]

9. Present the standing waves created in the fife closed at both ends.

The fife is closed at both ends.

[Illustration 8]

10. What is the fundamental frequency of a a vibrating air column in a fife closed at both ends?

The situation is analogous to that of a tight stringstringstring attached at both ends!

[Illustration 9]

11. Present the standing waves created in the fifefifefife closed at one end.

Fife closed at one end.

[Illustration 10]

12. What is the fundamental frequency of a vibrating air column in the fife closed at one end?

Vibration frequency in this case:

[Illustration 11]

[Illustration interactive]

Lesson summarym20ee5edb7875a29f_1528450119332_0Lesson summary

The vibrating body such as a string, an air column, a membrane, etc. is the basic element of every musical instrument. They create standing waves, which are the result of superposition of waves which move in opposite directions and consist of:
- nodes - places where the particles of the medium do not vibrate;
- antinodes - places where the amplitude of vibration of the medium particles is maximal.
The distance between two neighbouring nodes is equal to half the wavelength running in the medium.
The pitch (frequency) of the sound emitted by the instrument depends on the longest (basic) wave that can be created in a vibrating element and is related to the size of this element.
In brass instruments the longer pipe corresponds to the lower basic frequency, and thus the lower sound.
In stringed instruments, the pitch of the sound depends on:
- string length; longer length - lower sound,
- string thickness; thinner string - higher sound,
- string tensile; greater tensile force - higher sound.m20ee5edb7875a29f_1527752263647_0The vibrating body such as a string, an air column, a membrane, etc. is the basic element of every musical instrument. They create standing waves, which are the result of superposition of waves which move in opposite directions and consist of:
- nodes - places where the particles of the medium do not vibrate;
- antinodes - places where the amplitude of vibration of the medium particles is maximal.
The distance between two neighbouring nodes is equal to half the wavelength running in the medium.
The pitch (frequency) of the sound emitted by the instrument depends on the longest (basic) wave that can be created in a vibrating element and is related to the size of this element.
In brass instruments the longer pipe corresponds to the lower basic frequency, and thus the lower sound.
In stringed instruments, the pitch of the sound depends on:
- string length; longer length - lower sound,
- string thickness; thinner string - higher sound,
- string tensile; greater tensile force - higher sound.

Selected words and expressions used in the lesson plan

antinodeantinodeantinode

brass instrumentsbrass instrumentsbrass instruments

fifefifefife

fife closed on both sidefife closed on both sidefife closed on both side

fife closed on one sidefife closed on one sidefife closed on one side

fife opened on both sidefife opened on both sidefife opened on both side

musical instrumentmusical instrumentmusical instrument

nodenodenode

standing wavestanding wavestanding wave

stringstringstring

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musical instrument1

standing wave1

string1

brass instruments1

fife1

fife closed on both side1

fife opened on both side1

fife closed on one side1

node1

antinode1

Scenariusz

Topicm20ee5edb7875a29f_1528449000663_0Topic

Lesson stages

Selected words and expressions used in the lesson plan