Difference between revisions of "ExpEYES/C3/Characteristics-of-Sound-Waves/English-timed"

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2. Hint: A bell or a clap can be used as source of sound.This is the circuit diagram.
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* Hint: A bell or a clap can be used as source of sound.This is the circuit diagram.
  
 
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Revision as of 17:24, 5 May 2016

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 plots
  • Fourier Transforms and
  • Circuit diagrams 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 rear-fractions.
02:48 Click on CH2 and drag to FIT.Voltage and frequency of SQ1 is 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, 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 178deg and 106deg to calculate 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.
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 tutorials 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 plots
  • 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.

Contributors and Content Editors

Madhurig, Pratik kamble, Sandhya.np14