PoojaMoolya: Created page with "{|border=1 || '''Time''' || '''Narration''' |- || 00:01 || Welcome to the spoken tutorial on '''Sound Waves'''. |- || 00:05 || In this tutorial we will, Form a standing wav..."

2020-09-15T05:18:20Z

Created page with "{|border=1 || '''Time''' || '''Narration''' |- || 00:01 || Welcome to the spoken tutorial on '''Sound Waves'''. |- || 00:05 || In this tutorial we will, Form a standing wav..."

New page

{|border=1
|| '''Time'''
|| '''Narration'''
|-
|| 00:01
|| Welcome to the spoken tutorial on '''Sound Waves'''.

|-
|| 00:05
|| In this tutorial we will,

Form a standing wave.

|-
|| 00:10
|| Form nodes and antinodes.

|-
|| 00:14
|| View various types of harmonics of a standing wave.

|-
|| 00:19
|| Calculate the wavelength and frequency of standing waves.

|-
||00:24
|| Here I am using,

'''Ubuntu Linux''' OS version 16.04

|-
|| 00:30
|| '''Firefox web browser''' version 62.0.3

|-
|| 00:35
|| To follow this tutorial learner should be familiar with '''Apps on Physics'''.

|-
|| 00:41
|| For the pre-requisite tutorials please visit this site.

|-
||00:46
|| Use the given link to download the '''Apps'''.

|-
|| 00:50
|| I have downloaded the '''Apps''' to my '''Downloads''' folder.

|-
||00:55
||In this tutorial we will use,

'''Standing Wave''' and '''Standing Longitudinal Waves Apps'''.

|-
|| 01:04
|| Right-click on '''standingwavereflection_en.htm''' file.

|-
|| 01:10
|| Select the option '''Open with Firefox Web Browser'''.

|-
|| 01:15
|| '''Standing Wave App''' opens in the '''browser'''.
|-
||01:19
|| In the green panel under '''Reflection''' we have two radio buttons.

'''from a fixed end ''' and '''from a free end'''.
|-
|| 01:29
|| By default '''Reflection from a fixed end''' is selected.
|-
|| 01:34
|| Below these radio buttons you can see, '''Reset''' and '''Start '''buttons.
|-
|| 01:39
|| '''Start '''button is a toggle for '''Start, Pause''' and '''Resume'''.
|-
|| 01:44
|| At the bottom of the green panel you can see

'''Incidenting wave''', '''Reflected wave '''and '''Resultant standing wave''' check-boxes.
|-
|| 01:54
|| These check-boxes are selected by default.
|-
|| 01:58
|| Click on the '''Start''' button.
|-
|| 02:01
|| On the yellow panel, observe the propagation of a wave in a string.

|-
|| 02:06
|| The red wave is the '''Incidenting wave'''.
|-
|| 02:10
|| The blue wave is the '''Reflected wave'''.

|-
|| 02:13
|| Observe that the reflected wave has a phase change of 180 degrees.
|-
|| 02:19
|| Here the incident and reflected waves have the same amplitude.
|-
|| 02:24
|| Let us uncheck the''' Reflected wave'''.

|-
|| 02:27
|| If we uncheck any of the check-boxes, we cannot see the corresponding wave.
|-
|| 02:33
|| Click the '''Reflected wave''' check-box to make it visible again.
|-
|| 02:37
|| Click on the '''Pause''' button to stop the propagation of the waves.
|-
|| 02:42
|| Here is the resultant '''standing wave'''.
|-
|| 02:45
|| This wave is formed due to the superposition of incident and reflected waves.

|-
|| 02:51
|| The resultant wave is the constructive superposition of the waves.
|-
|| 02:56
|| Now I will show the superposition of waves in a step-by-step manner.
|-
|| 03:01
|| Click on the '''Single steps''' radio button to show the animation step-by-step.
|-
|| 03:07
|| Here a drop down to show various time periods is seen.

|-
|| 03:13
|| By default it is '''T by 8'''.

We will leave it as it is.
|-
|| 03:19
|| Now click the '''Resume''' button three times to show different superpositions.
|-
|| 03:25
|| This is destructive interference of sound waves.

|-
|| 03:29
|| Here the waves are out of phase.

So they subtract each other and form a straight line.
|-
|| 03:37
|| Click on '''Resume''' button again.
|-
|| 03:40
|| This is an intermediate superposition of waves.

|-
|| 03:44
|| It lies between the constructive and destructive superpositions.
|-
|| 03:49
|| Again click on the''' Resume''' button.
|-
|| 03:52
|| This is constructive interference of the waves.

|-
|| 03:56
|| This is the amplitude of the resulting standing wave.

|-
|| 04:00
|| It is the sum of incident and reflected waves.
|-
|| 04:04
|| For the time period '''T by 8''', one '''cycle''' takes three steps to complete.

|-
|| 04:10
|| '''T by 8''' means 1/8th of the total time period.
|-
|| 04:16
|| Let us select '''T by 24 ''' from the drop-down.

|-
|| 04:21
|| Click on the ''' Resume '''button continuously to see various superpositions.

|-
|| 04:27
|| Observe that one superposition cycle now takes five steps.
|-
|| 04:33
|| You can try other options given in the drop-down on your own.
|-
|| 04:38
|| After the reflection from the fixed end, you can see '''A '''and '''N''' on the string.
|-
|| 04:45
|| Here''' N''' is a''' Node''' and '''A''' is an''' Antinode'''.
|-
||04:50
|| Let us define a '''Node''' and an '''Antinode.'''

|-
|| 04:54
|| '''Node '''is the point where the particles do not have any motion.

|-
|| 04:59
|| '''Antinode''' is the point where the particle oscillates with maximum amplitude.

|-
|| 05:06
|| As an assignment

Using '''Reflection from free end''' option, show the formation of standing waves.

|-
|| 05:15
|| Observe the reflection by selecting various time period options.

Explain your observation.
|-
||05:23
|| Let us move on to '''Standing longitudinal wave App'''.
|-
|| 05:27
|| To open the''' App '''right-click on '''standinglongitudinalwaves_en.htm '''file.

|-
|| 05:35
|| Select the option '''Open with Firefox Web Browser'''.
|-
||05:39
|| The '''App''' opens in the browser.
|-
|| 05:42
|| Here is the information related to the '''App''' interface.
|-
|| 05:47
|| Scroll down to see the interface completely.
|-
|| 05:51
|| This interface shows a tube filled with air molecules.

|-
|| 05:57
|| The blue dots inside the tube represent the air molecules.
|-
|| 06:03
|| Here we can see two plots.

|-
|| 06:06
|| '''Displacement of particles''' and '''Divergence from average pressure'''.
|-
|| 06:12
|| X axis represents the length of the tube.

|-
|| 06:16
|| '''Δ(delta)x''' is the change in displacement of molecules from the equilibrium position.

|-
|| 06:22
|| '''Δ(delta)p''' is the '''Divergence from average pressure.'''
|-
|| 06:26
|| Observe the pink and red waves.

|-
|| 06:30
|| They show the instantaneous movement of air molecules.
|-
|| 06:35
|| In the green panel, under the heading''' Form of tube''', we have three radio buttons.
|-
|| 06:42
|| By default '''both sides open''' radio button is selected.
|-
|| 06:47
|| Next, under '''Vibrational mode''' we see two buttons, '''Lower '''and '''Higher'''.
|-
|| 06:54
|| By default, the '''App '''shows the lowest '''Vibrational mode'''.

|-
|| 06:59
|| The lowest '''vibrational mode''' of the system is known as '''fundamental'''.

|-
|| 07:04
|| '''Fundamental vibrational mode''' is the first harmonic followed by higher harmonics.

|-
|| 07:10
|| We can change the''' Length of the tube''' in this box.
|-
|| 07:14
|| '''Length of the tube''' can be varied between 1''' meter''' to 10''' meters'''.

|-
|| 07:20
|| The '''App''' calculates the '''Wavelength''' and '''Frequency '''based on the length of the tube.

|-
|| 07:26
|| Click the '''Higher '''button continuously.

It shows 5 overtones for the six harmonical vibrations.

|-
|| 07:34
|| Press '''F5''' key on the keyboard to reset the '''App'''.

|-
|| 07:39
|| Observe the motion of air molecules.

|-
|| 07:43
|| Molecules in the middle of the tube do not displace from the mean position.

|-
|| 07:49
|| Therefore in the '''Displacement of particles''' graph, '''node''' is in the middle.

|-
|| 07:55
|| Observe that particles at the extreme positions are oscillating in and out.

|-
|| 08:02
|| Here particles oscillate with maximum amplitude.

|-
|| 08:07
|| Therefore '''antinode''' is present at the extreme ends of the X- axis.

|-
|| 08:13
|| Let us move to the second graph.

|-
|| 08:16
|| Observe the movement of particles inside the tube and graph simultaneously.

|-
|| 08:22
|| In the graph, movement of the pink wave shows the changes in the pressure.

|-
|| 08:28
|| As the particles move towards the center, they get compressed.

So pressure increases.

|-
|| 08:35
|| When they move away pressure decreases.

|-
|| 08:39
|| Under '''Form of tube''', select '''one side open''' radio button.

|-
|| 08:45
|| Observe the movement of particles in this form of the tube.

|-
|| .08:49
|| Here particles at the closed end are not moving.

Therefore the pressure is maximum at this end.

|-
|| 08:58
|| Let us calculate the wavelength in this form of the tube.

|-
|| 09:03
|| First let us define wavelength.

|-
|| 09:06
|| Wavelength is the distance between two consecutive peaks.

|-
|| 09:10
|| Click on the '''Higher''' button to show the first overtone.

|-
|| 09:14
|| We have to calculate the wavelength of first overtone wave.

|-
|| 09:19
|| Mathematically we can write, '''L = n by 4 of lambda'''

|-
|| 09:25
|| There '''L''' is length of the tube and '''lambda''' is the wavelength.

‘'''n'''’ can take values from 1 to n.

|-
|| 09:34
|| By rearranging the equation we can write this as

'''lambda= 4L upon n'''
|-
|| 09:41
|| Let us calculate the wavelength.

|-
|| 09:44
|| The wavelength of the first overtone is three-fourth of the complete wave.

Here the value of n is 3.
|-
|| 09:54
|| From the '''App, '''value of length of tube can be taken as '''L'''.

|-
|| 09:59
|| Therefore the calculated value of wavelength is 1.33 '''metre'''.

|-
|| 10:05
|| This is the wavelength of first overtone mode of vibration.
|-
|| 10:10
|| Now we will calculate the frequency of the wave.

|-
|| 10:14
|| The number of complete oscillations per second is the frequency of a sound wave.

|-
|| 10:21
|| It is measured in '''hertz (Hz)'''.

|-
|| 10:24
|| Frequency is calculated using the formula.

'''f=c/λ''' (f is equal to c upon lambda)

|-
|| 10:31
|| '''λ (lambda)''' is wavelength and '''c''' is speed of sound wave
|-
|| 10:37
|| The''' App ''' shows the value of speed of sound wave as 343.5 '''metre per second '''at 20 '''degree Celsius'''.
|-
|| 10:48
|| Let us calculate the frequency of the same wave.
|-
|| 10:51
|| Substitute the values for the above formula from the '''App'''.

|-
|| 10:57
|| The value for the frequency is 258.27 '''Hertz'''.

|-
|| 11:03
|| This value is comparable to the value shown in the '''App'''.
|-
||11:07
||Make a tabular column to show the wavelength and frequency for 6 harmonical modes.
|-
|| 11:15
|| Click on the '''Higher '''button to go to next harmonic.
|-
|| 11:19
|| Similarly I have calculated frequency and wavelength for higher harmonics.
|-
|| 11:27
|| As an assignment, Change the length of tube to 8 metre.

|-
|| 11:33
|| Calculate the wavelength and frequency for different vibrational modes.
|-
|| 11:38
|| Another assignment.

Change the '''form of tube''' to '''both sides closed ''' and explain the graphs.

|-
|| 11:46
|| Let us summarize.

|-
|| 11:48
|| Using these '''Apps''' we have,

Formed a standing wave.

|-
|| 11:55
|| Formed nodes and antinodes.

|-
|| 11:59
|| Viewed various types of harmonics of a standing wave.

|-
|| 12:04
|| Calculated the wavelength and frequency of standing waves.

|-
|| 12:09
|| These '''Apps '''were created by '''Walter-fendt''' and his team.

|-
|| 12:13
|| The video at the following link summarizes the Spoken Tutorial project.

Please download and watch it.
|-
|| 12:21
||The '''Spoken Tutorial Project''' team conducts workshops and gives certificates.

For more details, please write to us.
|-
|| 12:31
|| Please post your timed queries on this forum.
|-
|| 12:35
||Spoken Tutorial Project is funded by MHRD, Government of India.

|-
|| 12:41
|| This is Himanshi Karwanje from IIT-Bombay.

Thank you for joining.
|-
|}

Apps-On-Physics/C2/Sound-waves/English-timed - Revision history

PoojaMoolya: Created page with "{|border=1 || '''Time''' || '''Narration''' |- || 00:01 || Welcome to the spoken tutorial on '''Sound Waves'''. |- || 00:05 || In this tutorial we will, Form a standing wav..."