View source for ExpEYES/C3/Characteristics-of-Sound-Waves/English-timed

{| border=1
||'''Time'''
||'''Narration'''

|-
|00:01
|Hello everyone. Welcome to this tutorial on '''Characteristics of Sound Waves'''.

|-
|00:08
| In this tutorial, we will learn to demonstrate:
How to generate a sound wave,
frequency response of a sound source,

how to calculate velocity of sound,
'''interference''' and '''beats''' of sound waves,
 
forced oscillations of a sound source.

|-
|00:29
|And, show:

'''Xmgrace plot'''s, 

'''Fourier Transforms''' and 

'''Circuit diagram'''s for our experiments.

|-
|00:38
| Here, I am using:
'''ExpEYES''' version 3.1.0,
'''Ubuntu Linux OS''' version 14.10.

|-
|00:49
| To follow this tutorial, you should be familiar with '''ExpEYES Junior''' interface. If not, for relevant tutorials, please visit our website. 

|-
|01:01
| Let's first begin with definition of sound.

'''Sound''' is a vibration that propagates as an audible mechanical wave of pressure & displacement.

|-
|01:13
|It requires a medium to propagate. The medium can be air, water or any metal surface.

|-
|01:22
| In this tutorial, we will carry out various experiments to show characteristics of sound waves.

|-
|01:30
|Let's perform an experiment to show frequency of sound waves.

|-
|01:35
|In this experiment, ground(GND) is connected to '''Piezo buzzer (PIEZO)'''.

'''Piezo buzzer (PIEZO)''' is connected to '''SQR1'''.

|-
|01:44
|'''Microphone (MIC)''' is connected to '''A1'''. Here, '''Piezo buzzer(PIEZO)''' is a source of sound.
This is the '''circuit diagram'''.

|-
|01:55
|Let's see the result on the '''Plot window'''.

|-
|01:59
|On the '''Plot window''', under '''Setting Square waves, '''set the frequency as ''3500Hz''. 

|-
|02:07
| Click on '''SQR1''' check-box. Frequency of '''SQR1''' is set to ''3500Hz''. A digitized sound wave is generated.

|-
|02:20
|Move the '''frequency''' slider to change the waveform.

|-
|02:27
| Click on '''SQ1''' and drag to''' CH2'''. Input data of '''SQ1''' is assigned to '''CH2'''. A square wave is generated.

|-
|02:40
| Drag the '''mSec/div''' slider to set in '''compressions''' and '''rarefactions'''.

|-
|02:48
| Click on '''CH2 '''and drag to '''FIT'''. Voltage and frequency of '''SQ1''' are displayed on the right-side.

|-
|02:59
| Move the frequency slider to set in sound waves.

|-
|03:04
| Sound wave produced by the '''Piezo buzzer''' is shown in black colour.

|-
|03:10
|'''Amplitude''' of the wave changes as '''Piezo buzzer''' is moved closer and away from the '''MIC''' respectively. 

|-
|03:19
|Now, we will demonstrate frequency response of '''Piezo buzzer'''. 

|- 
|03:24
| On the '''Plot window''' click on '''EXPERIMENTS''' button. '''Select Experiment''' list opens. Click on ''' Frequency Response''' from the list.

|-
|03:39
| Two new windows '''Audio Frequency response Curve''' and '''Schematic''' open. '''Schematic''' window shows the circuit diagram of the experiment.

|-
|03:52
| On the '''Audio Frequency response Curve''' window, click on ''' START''' button.

|-
|03:59
| '''Frequency response''' of the '''Piezo buzzer''' is set in. '''Frequency response''' has maximum '''amplitude''' at ''3700Hz''. 

|-
|04:11
| On the same window, click on '''Grace''' button. '''Grace''' window opens showing '''Frequency response Curve'''.

|-
|04:22
|Now, we will measure velocity of the source of sound.

|-
|04:27
| On the '''Plot window''', click on '''EXPERIMENTS''' button.
'''Select Experiment''' list opens. Click on '''Velocity of Sound''' from the list.
|-
|04:41
|Two new windows '''EYES Junior: Velocity of Sound''' and '''Schematic''' open. '''Schematic''' window shows the '''circuit diagram''' of the experiment.

|-
|04:55
| On '''EYES Junior: Velocity of Sound''' window, click on '''Measure Phase''' button.

|-
|05:02
| We can obtain different '''Phase''' values by changing the distance between '''MIC''' and '''Piezo buzzer'''.

|-
|05:11
|Click '''Measure Phase''' button to obtain different '''Phase''' values.

|-
|05:16
|From the various '''Phase''' values, we will use ''178 deg'' and ''106 deg'' to calculate the velocity of sound.

|-
|05:28
|We can obtain these values when '''Piezo''' is kept close and ''2cm'' away from the '''MIC'''. 

|-
|05:37
| To obtain accurate results, ensure that '''MIC''' and '''Piezo buzzer''' are placed on the same axis. 

|-
|05:45
| To calculate the value of '''velocity of sound''', we have the formula as shown.
Velocity of sound obtained from the experiment is 350m/sec.

|-
|05:59
|As an assignment, calculate the value of '''wavelength''' of sound. Formula: '''λ= v/f'''(Lambda = v upon f).

|-
|06:09
| Now, we will demonstrate:
'''Interference''',

'''Beats''', 

'''Xmgrace plot''' and 

'''Fourier Transform''' of the two sources of sound.

|-
|06:20
| To show '''Grace''' plots in the experiments,

|-
|06:23
|make sure that you have installed:

'''python-imaging-tk''',

'''grace''',

'''scipy''' and

'''python-pygrace''' on your system.

|-
|06:34
|In this experiment, we use two Piezo buzzers as source of sound. 

|-
|06:41
| In this experiment, '''Piezo 1''' is connected to '''SQR1''' and ground'''(GND)'''. '''Piezo 2''' is connected to '''SQR2''' and ground'''(GND)'''. This is the circuit diagram.

|-
| 06:56
| Let's see the result on the '''Plot window'''. 

|-
|07:00
| On the '''Plot window''', set frequency as ''3500Hz''. 

|-
|07:06
|Click on '''SQR1''' and '''SQR2''' check-boxes. Frequency of '''SQR1 '''and''' SQR2''' is set to “3500Hz”. 

|-
|07:20
|A digitized sound wave is generated.

|-
|07:24
|Move the '''frequency''' slider to change the waveform.

|-
|07:29
|Click on '''EXPERIMENTS''' button and select '''Interference of Sound'''. '''EYES: Interference of Sound''' window opens.

|-
|07:39
|At the bottom of the window, change '''NS''', that is, '''number of samples''' value to ''1000''.

|-
|07:48
|Click on '''SQR1''' and '''SQR2''' check-boxes. Click on '''START''' button. '''Interference''' pattern is seen. 

|-
|08:00
|Now, click on '''Xmgrace''' button. A new window opens with a '''Grace''' pattern.

|-
|08:08
|Now, we will show '''Beats''' pattern.

|-
|08:11
| Click on '''EXPERIMENTS''' button and select '''Interference of Sound'''.
'''EYES: Interference of Sound''' window opens.

|-
|08:20
| At the bottom of the window, click on '''SQR1 '''and '''SQR2''' check-boxes.

|-
|08:28
|Click on '''START''' button. '''Beats''' pattern appears.

|-
|08:33
|Now, click on '''Xmgrace''' button. A new window opens with a '''Grace''' pattern.

|-
|08:42
| Click on '''FFT'''. A new '''window''' opens with '''Fourier Transform'''.

|-
|08:49
|To know more about '''Fourier Transform ''', please visit this webpage.
'''https://en.wikipedia.org/wiki/Fourier_transform'''.

|-
|08:55
|Let us perform an experiment to show a low frequency sound wave. This is the '''circuit diagram'''.

|-
|09:03
| Click on '''EXPERIMENTS''' button and select '''Interference of Sound'''. '''EYES: Interference of Sound''' window opens.

|-
|09:13
| At the bottom of the window, set the value of '''SQR1''' to ''100'' and check the box.

|-
|09:21
|Click on '''START''' button, a low '''amplitude''' wave is displayed.

|-
|09:29
| Click on '''FFT''' to obtain a '''Grace''' plot of '''Fourier Transform'''.

|-
|09:34
| Let's summarize.

|-
|09:36
|In this tutorial, we have learnt to demonstrate:
how to generate a sound wave,

'''Frequency response''' of a sound source, 

how to calculate velocity of sound waves,

'''Interference''' and '''Beat''' pattern of sound waves, 

'''forced oscillations''' of sound source. 

|-
|09:56
|And, have shown:

'''Xmgrace plot'''s, 

'''Fourier Transforms''' and 

'''Circuit diagrams''' for our experiments.

|-
| 10:04
|As an Assignment- 

Capture a '''sound burst''' 

Hint: A bell or a clap can be used as source of sound. This is the circuit diagram.

|-
|10:15
|This video summarizes the '''Spoken Tutorial''' project. If you do not have good bandwidth, you can download and watch it.

|-
|10:24
|We conduct workshops using Spoken Tutorials and give certificates. Please contact us.

|-
|10:32
|The Spoken Tutorial Project is funded by NMEICT, MHRD, Government of India.

|-
|10:40
|This tutorial is contributed by Kaushik Datta and Madhuri Ganapathi. This is Sakina Sidhwa.
Thank you for joining.

|}