ExpEYES/C3/Characteristics-of-Sound-Waves/English-timed
From Script | Spoken-Tutorial
| 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 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. |
| 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 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. |
