I spent hours trying to understand why pressure and displacement graphs had a phase difference of pi/2. I finally understood I because of your video! And it was so simple! Thanks you so much sir!
Excellent! I just enlightened myself. I've been struggling to understand and thanks to you now that I understand everything. This video deserves a lot more likes!
THANK YOU VERY MUCH SIR.... EXPLAINATION IS AWSOME... THIS IS THE FIRST VIDEO THAT I SAW WHEN I DIDNT UNDERSTAND THE TOPIC. TODAY I HAD MY JEE MAIN EXAM (ENTRANCE EXAM FOR ENGINEERING IN INDIA) . IT HELPED ME ALOT EVEN DURING MY REVISION. THANK YOU SIR. LOVE FROM India!!!
Thank you for this excellent explanation. I had trouble visualizing how the two graphs are linked and this video was nothing but perfect for me. Even though your videos cater mainly for Singapore O level content, it is nice to refresh my basics as a Singapore A level student. Keep up the good work!
It is really wholesome to see that you are still replying to these comments eventhough the video is 5 years old. I had to skip a few of my physics classes due to some private reasons but your videos did helped me to understand the topic easily. no other channel explains compressions and rarefractions like you do! keep it up
Thank you for your kind comments! I am glad that the videos helped you in some ways! There aren't much comments anyway and it takes me 3 minutes to reply. The comments (like yours) helps bring me joy that my video is still useful! Thank you! 😄
Thank you, this is an excellent video! Can you tell me how compressions and rarefactions are positioned in relation to a standing wave? For example, in a Reuben's tube? Thank you 🙏
Thank you for this interesting question! I actually did not know the answer to your question but I did some reading up and this is what I understood. A standing wave is created due to the interaction between the wave and its reflected counterpart. The features of a standing wave is that it creates nodes (where displacement is always zero) and antinodes (where displacement is maximum). For standing waves, the compressions AND rarefactions are both positioned at the nodes! You might think how is this possible? It is because at the nodes, when it becomes compression, half a period later, it will become rarefaction, then half a period, it becomes a compression again, then the cycle repeats. As an analogy, this pattern is similar to a person who is in favour and both left and right side come rushing towards him/her (like a compression) and he/she can't move (node -> zero displacement). Then both the left and right crowd wants a piece of hm/her and pulls him/her apart both left and right (like a rarefaction) but due to equal forces, he/she still can't move (node). Anyway, if you still can't visualise the above analogy, please look at this website. It has very clear animations on how nodes becomes compression then rarefaction. www.acs.psu.edu/drussell/demos/standingwaves/standingwaves.html Hope this helps!
@@boringphysicsteacher ah yes, of course, that makes so much sense! Thank you so much for taking the time to research and reply, I really appreciate it. You are an excellent teacher 👍 And the link you gave is incredibly helpful too
@@weatherinme6882 Thank you for your question! If the wave direction is to the left, positive displacement means the particle is still on the right side compared to zero displacement. It is because before you even start with a wave, you will have to first decide which direction is considered positive ( which is usually towards right). It is fixed regardless of which direction your wave is moving. An similar analogy is if you decide that moving right is positive direction, it will remain the same for all moving objects regardless of moving left or right. An object moving right will have more and more positive displacement while another object moving left has a more and more negative displacement. If we use as what you suggested, whenever you see a positive displacement, you can't tell if an object is on the right because it is moving right or it is actually on the left because it is moving left. Hope this clears things up
hi sir may i know how do we identify if its a compression or rarefaction at a particular time, if we are given a a displacement time graph of the longitudinal wave instead?
Hello! Thank you for your question! Actually, off the cuff answer is the moment when the displacement of the particle changes from negative to positive should be a compression. By extension ( or on the flip side), when displacement of the particle changes from positive to negative is when it is at a rarefaction. As for the reason, i think I will have to produce a video to explain it. :P
I have made a series of videos on waves. Maybe you could go through them and see what I missed out. Thank you for your support! ruclips.net/p/PLAELz55fSKNzgfal5eZf_EXg_c-MZNPtt
Thank you for your question. I assumed that by saying a wave having a negative velocity, you meant the wave is travelling in the opposite direction. The short answer is that there is no difference in the method of identifying compression and rarefaction for both positive and negative wave velocity. It is because for a displacement-distance graph is a snap-shot of the wave at a single moment in time. Compressions and rarefaction are at that position at the point in time and which direction they are travelling towards (positive or negative) next does not affect where they are now.
Thank you for your question! It is not explained in this video. But to answer your question: Assuming right as the positive direction, the particle that is at the compression is having the maximum velocity/speed and moving towards right (positive direction). The particle at the rarefaction is also at maximum speed BUT is moving towards LEFT (negative direction). So depending on your definition, some will say that it is the minimum velocity as it has a negative sign. In short, both compression and rarefaction has maximum speed but compression is moving in + direction but rarefaction is moving in - direction.
@@boringphysicsteacher sir but you said in your video that in rarefraction the particle is being pulled equally so it does not move..so shouldn't its velocity be zero??
@@vatsalgoyal4711 Hi! Sorry to have caused some confusion. When I mentioned that in rarefaction, the particle is being pulled equally so it does not have displacement was meant to be an Analogy to help students better visualise. The animation that I showed are not the actual movement of the particles of the longitudinal waves. They are used to illustrate that in a compression and rarefaction, how are the displacement of the particles be represented as positive, negative or zero. The actual speed and movement of the particles in the longitudinal wave is described by their respective displacement-time graph (which is a sine or cosine wave graph). From there, you need to apply from kinematics that velocity is the gradient slope of displacement-time graph. When displacement is zero (either a compression or rarefaction) for a sine/cosine wave, the gradient slope is the steepest (meaning velocity having the largest magnitude). During a compression, the gradient slope (meaning velocity) is positive and in a rarefaction, the gradient slope is negative. I know that this is not easy to understand and I apologise again for causing confusion for you on my choice of animation and explanation in this video.
@@boringphysicsteacher Thank you very much sir for taking your precious time to give a detailed explanation.. nevertheless your video on this topic was the best I came across on RUclips!
@@boringphysicsteacher Hello teacher, may I ask why does the particle at the rarefraction/compression move? I thought it either vibrates or moves up and down? Since on the displacement distance graph it has 0 displacement. And also, why do we need to know the velocity of the particle of the wave? Does the velocity calculated refer to the speed of the wave or is it the speed of the particle? Thank you!
![Noob To Max With DRAGON REWORK In Blox Fruits [FULL MOVIE]](http://i.ytimg.com/vi/LnBMOinoOvA/mqdefault.jpg)
Hands down one of the simplest ways, someone has explained this concept
Thank you so much sir!!
Thank you for your generous and kind comment! Appreciate it!
I struggled with these kinds of questions for so long, thank you so much
Happy to help!
Everything i needed about this topic is included..
Thank u sir.! This was a clear video!
Just got amazed how simply you explain this topic. Thank you sir.
Thank you for your kind comments! Glad to be of help!
I spent hours trying to understand why pressure and displacement graphs had a phase difference of pi/2. I finally understood I because of your video! And it was so simple! Thanks you so much sir!
Glad that the video helped you understand the concept!
Excellent! I just enlightened myself. I've been struggling to understand and thanks to you now that I understand everything. This video deserves a lot more likes!
Thank you for your kind comments!
THANK YOU VERY MUCH SIR.... EXPLAINATION IS AWSOME... THIS IS THE FIRST VIDEO THAT I SAW WHEN I DIDNT UNDERSTAND THE TOPIC. TODAY I HAD MY JEE MAIN EXAM (ENTRANCE EXAM FOR ENGINEERING IN INDIA) . IT HELPED ME ALOT EVEN DURING MY REVISION. THANK YOU SIR. LOVE FROM India!!!
Very happy to be of help!
Thank you sir 🤩
You cleared my confusion easily .
5 - star explanation.
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Great 👍! Glad to be of help.
Great Explanation in simplest way I was really struggling to Understand the Logic Behind the Graphs Before.. Good Content 👍
Thank you! Glad to be of help!
Thank you for this excellent explanation. I had trouble visualizing how the two graphs are linked and this video was nothing but perfect for me. Even though your videos cater mainly for Singapore O level content, it is nice to refresh my basics as a Singapore A level student. Keep up the good work!
Thank you for your kind comments! :)
you explained this so well - a true art!
Clear video. My students understand this concept better using your video. Thank you!
Glad to be of help!
Thank you so much for this wonderful video! It really made learning this topic so much more easier :D
Awesome! Loved the explanation and the visuals! What a clear picture of the concept it gives! Thank you ❤️
Thank you for your kind comments!
thanks a lot, finally someone had the animation and graph side by side.
Bow to you......why you have less than 2k subscribers. You are amazing teacher
Thank you for your kind comments! Maybe it is because I am boring :D
@@boringphysicsteacher 😁
explain in a clear and easy way，thank you so much sir
Thank you for your kind comments! Hope the video is of help to you!
Best video ever about the topic
Came across this video and you've made it easier to understand, thank you so much.
Glad it helped!
It is really wholesome to see that you are still replying to these comments eventhough the video is 5 years old. I had to skip a few of my physics classes due to some private reasons but your videos did helped me to understand the topic easily. no other channel explains compressions and rarefractions like you do! keep it up
Thank you for your kind comments! I am glad that the videos helped you in some ways! There aren't much comments anyway and it takes me 3 minutes to reply. The comments (like yours) helps bring me joy that my video is still useful! Thank you! 😄
This video cleared all my doubts.Thank you.!
Glad it helped
Really very good video sir, cleared my doubts, you helped a lot me today thanks so much 🙏
It's my pleasure
thank you very much , very useful, liked the analogy of a famous person, good sense of teaching
Thank you for your kind words! It means a lot coming from another physics educator!
Thank you very much for this video, sir! It's just what I needed to clear my doubts
You are welcome!
I understood very easily sir. you helped me a lot sir .thank you so much sir
You are most welcome
Well known terms understanding explanation and animation more helpfull, this vidio should in every school, thnks, india
Thank you for your kind comments!
Really very good viedo you made it very simple to understand sound wave
Thank you for your kind comments! Really appreciate it! :D
You are really a very good teacher sir❤
Thanks really helped me solve few tough questions. Gonna subscribe and share your video.
Thank you!
You are amazing physics teacher 👍🙏🙏🙏❤️
Thank you for your kind comments!
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It was very useful, sir.
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Thank you for your kind comments! Hope it is of help! :)
Excellent Explanation!
Thank you so much!! This video helped me a lot!
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Well done ❤🎉🎉🎉
Thank you, this is an excellent video! Can you tell me how compressions and rarefactions are positioned in relation to a standing wave? For example, in a Reuben's tube? Thank you 🙏
Thank you for this interesting question! I actually did not know the answer to your question but I did some reading up and this is what I understood.
A standing wave is created due to the interaction between the wave and its reflected counterpart. The features of a standing wave is that it creates nodes (where displacement is always zero) and antinodes (where displacement is maximum). For standing waves, the compressions AND rarefactions are both positioned at the nodes! You might think how is this possible? It is because at the nodes, when it becomes compression, half a period later, it will become rarefaction, then half a period, it becomes a compression again, then the cycle repeats.
As an analogy, this pattern is similar to a person who is in favour and both left and right side come rushing towards him/her (like a compression) and he/she can't move (node -> zero displacement). Then both the left and right crowd wants a piece of hm/her and pulls him/her apart both left and right (like a rarefaction) but due to equal forces, he/she still can't move (node).
Anyway, if you still can't visualise the above analogy, please look at this website. It has very clear animations on how nodes becomes compression then rarefaction.
www.acs.psu.edu/drussell/demos/standingwaves/standingwaves.html
Hope this helps!
@@boringphysicsteacher ah yes, of course, that makes so much sense! Thank you so much for taking the time to research and reply, I really appreciate it. You are an excellent teacher 👍 And the link you gave is incredibly helpful too
@@amybroom9452 Thank you for your kind comments! I actually benefited from your question and deepened my own understanding of the topic! 😃
this was very helpful, thank you very much!!!
You're very welcome!
Thank you for subtitles
if the wave direction is to the left, does positive displacement mean it moves to the left?
@@weatherinme6882 Thank you for your question! If the wave direction is to the left, positive displacement means the particle is still on the right side compared to zero displacement. It is because before you even start with a wave, you will have to first decide which direction is considered positive ( which is usually towards right). It is fixed regardless of which direction your wave is moving.
An similar analogy is if you decide that moving right is positive direction, it will remain the same for all moving objects regardless of moving left or right. An object moving right will have more and more positive displacement while another object moving left has a more and more negative displacement.
If we use as what you suggested, whenever you see a positive displacement, you can't tell if an object is on the right because it is moving right or it is actually on the left because it is moving left.
Hope this clears things up
Thank you mate!! really helpful
Thank you...👍
Thank u very much !
🇱🇰
Great video!
it was a very helpful video. thanks a lot!!
Such a clear and concise explanation. You have saved me. Thank you 🙏
Great to hear!
hi sir may i know how do we identify if its a compression or rarefaction at a particular time, if we are given a a displacement time graph of the longitudinal wave instead?
Hello! Thank you for your question! Actually, off the cuff answer is the moment when the displacement of the particle changes from negative to positive should be a compression. By extension ( or on the flip side), when displacement of the particle changes from positive to negative is when it is at a rarefaction. As for the reason, i think I will have to produce a video to explain it. :P
As promised........Check out this video! :)
Life saver for my physics test tmr
All the best for your test!
Best explanation
Thank you for your kind comments!
Quite useful, thnx sir ☺
Thank you for your kind comments!
Thank you so much for clearing the concept 😊
My pleasure 😊
Thank you sir 😊
Thank you so much. This was very helpful :)
Glad it was helpful!
very helpfull thanks
Is this same for transverse waves?
Hi, would like to clarify. Which aspect of transverse wave are you referring to?
Thank you Sir
Good video as always:) Sir can make video abt transverse waves too?
I have made a series of videos on waves. Maybe you could go through them and see what I missed out. Thank you for your support! ruclips.net/p/PLAELz55fSKNzgfal5eZf_EXg_c-MZNPtt
This was very helpful. Thank you!
Excellent
Nah dude, You ain't boring
Hehe..... Thanks! 😄
Very helpful sir!
Loved it
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Most welcome!
WWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW GREAT TEACHER
Thanks a lot
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Thanks!
what if the wave has a negative velocity itself?
Thank you for your question. I assumed that by saying a wave having a negative velocity, you meant the wave is travelling in the opposite direction. The short answer is that there is no difference in the method of identifying compression and rarefaction for both positive and negative wave velocity. It is because for a displacement-distance graph is a snap-shot of the wave at a single moment in time. Compressions and rarefaction are at that position at the point in time and which direction they are travelling towards (positive or negative) next does not affect where they are now.
Sir is the velocity maximum or minimum at a compression and rarefaction?
Thank you for your question! It is not explained in this video. But to answer your question:
Assuming right as the positive direction, the particle that is at the compression is having the maximum velocity/speed and moving towards right (positive direction).
The particle at the rarefaction is also at maximum speed BUT is moving towards LEFT (negative direction). So depending on your definition, some will say that it is the minimum velocity as it has a negative sign.
In short, both compression and rarefaction has maximum speed but compression is moving in + direction but rarefaction is moving in - direction.
@@boringphysicsteacher sir but you said in your video that in rarefraction the particle is being pulled equally so it does not move..so shouldn't its velocity be zero??
@@vatsalgoyal4711 Hi! Sorry to have caused some confusion.
When I mentioned that in rarefaction, the particle is being pulled equally so it does not have displacement was meant to be an Analogy to help students better visualise. The animation that I showed are not the actual movement of the particles of the longitudinal waves. They are used to illustrate that in a compression and rarefaction, how are the displacement of the particles be represented as positive, negative or zero.
The actual speed and movement of the particles in the longitudinal wave is described by their respective displacement-time graph (which is a sine or cosine wave graph). From there, you need to apply from kinematics that velocity is the gradient slope of displacement-time graph. When displacement is zero (either a compression or rarefaction) for a sine/cosine wave, the gradient slope is the steepest (meaning velocity having the largest magnitude). During a compression, the gradient slope (meaning velocity) is positive and in a rarefaction, the gradient slope is negative.
I know that this is not easy to understand and I apologise again for causing confusion for you on my choice of animation and explanation in this video.
@@boringphysicsteacher Thank you very much sir for taking your precious time to give a detailed explanation.. nevertheless your video on this topic was the best I came across on RUclips!
@@boringphysicsteacher Hello teacher, may I ask why does the particle at the rarefraction/compression move? I thought it either vibrates or moves up and down? Since on the displacement distance graph it has 0 displacement. And also, why do we need to know the velocity of the particle of the wave? Does the velocity calculated refer to the speed of the wave or is it the speed of the particle? Thank you!
Thank you so much sir :))
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5:30
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4:36
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Thanks for the compliments!
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