Sound Analyzer JavaScript Simulation Applet HTML5

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Sound

Need Safari on iOS, Chrome will not render the sound on iOS.

Need Chrome on the rest.

Translations

Code	Language		Translator	Run

Credits

Felix J. Garcia Clemente; Tze Kwang Leong; Loo Kang Wee

WebPage to measure sound wave resonance in pipes with predictive scripts of Closed-Closed Closed-Open Ends and the estimated length of the pipe producing the sound waves. App

Worksheet

6. Resonance in Pipes

Problem Statement/Description

The oldest object referred to as a musical instrument was a simple flute, which dates back as far as 67,000 years. Stationary waves produced in the air columns are responsible for the tones produced by the flute and other wind instruments. Stationary waves can also be set up in the medium such as string and water. The following tasks will investigate the characteristics of the stationary waves in the air column.

Task 7a

Learning Objective

The student will learn that the wavelength of the sound wave is independent of the width of the material of the pipe. Students will learn the longest wavelength of the sound is twice the length of an open pipe and four times the length of a closed pipe. They will also learn the formula for the second harmonics.

Prerequisite knowledge

Knowing the formula v = f λ

Motivation

Try blowing the straw with both ends open and then with one end closed. Did you notice they sound different? Can you explain why they sound different?

Equipment

Smartphone, various tubes of different width, length and materials that are flat on both end (eg. straws, toilet roll, PVC pipe)

Go to URL: https://iwant2study.org/lookangejss/04waves_14sound/ejss_model_sound_analyzer/sound_analyzer_Simulation.xhtml $C:\Users\MOE-14838D\Pictures\phone photo\20151119_110148.jpg$
Blow into the straw with a steady stream of air to produce a consistent tone.
Pause the simulation.
Record the fundamental frequency of the straw (i.e. lowest frequency) and the 2nd harmonics (2nd lowest frequency) and 3rd harmonics (3rd lowest frequency)
Given the speed of sound in air is 340 ms-1, calculate the respective wavelength of the sound wave.
Reset the simulation and repeat step 2 to 5 with your hand placed on one end of the straw. $C:\Users\MOE-14838D\Pictures\phone photo\20151119_110200.jpg$
Repeat steps 3 to 7 with different pipes.
By plotting graphs or otherwise, suggest the relationship between the properties of the pipes and
1. the longest wavelengths of the sound wave for the open pipe.
2. the longest wavelengths of the sound wave for the closed pipe.
3. the second longest wavelengths of the sound wave for the open pipe.
4. The second longest wavelengths of the sound wave for the closed pipe.
By considering the relationship you found in step 9, could you deduce what causes the difference in sound when you closed the end of the pipe?

Task 7b:

Challenge

As a class, you have to perform the song “Twinkle Twinkle Little Star” using only the apparatus given.

Apparatus

Each group is given only a single straw*, ruler and scissors.

*Class will get a total of 6 straws. Some groups may get more straws if there are less than 6 groups.

Reminder: Present your workings clearly on your whiteboard.

Note	Frequency / Hz
C	1047
D	1175
E	1319
F	1397
G	1568
A	1760
B	1976

"Twinkle Twinkle Little Star" music notation in the key of C
CC GG AA G
FF EE DD C
GG FF EE D
GG FF EE D
CC GG AA G
FF EE DD C

Extra challenge: Try performing using the pipe with one end closed instead of both ends open. Explain what you hear.

Note: Waves are dynamic in nature. Usual representations are static. Best to complement the visual
with an applet or simulation
Applets to study the air particles movement in relation to the frequency:
https://sg.iwant2study.org/ospsg/index.php/interactive-resources/physics/04-waves/02-general-waves/111-standing-waves-in-a-pipe

Videos

Demo video https://www.youtube.com/watch?v=2u_djWwm0u8

Videos to animate standing wave formed in an open-open air column:
https://www.youtube.com/watch?v=BhQUW9s-R8M Standing waves in open tubes | Mechanical waves and sound | Physics | Khan Academy by khanacademymedicine