Ive looked all over for a video to explain this, and you did it perfect job just clicked. This was most likely due to the fact that you used actual obiects in your video thanks a lot 😀😀
This is away better than the other videos on the internet. You explained it very well. Please make more videos on such kind of practicals. Keep up your good work!
Wow, first explanation of sound wave mechanics that ever clicked in my brain. Thank you! The most educational 6min 49 sec ever!. So far so good. Now, why does the bottle have a much lower resonant pitch than the graduated cylinder, even though it is much shorter? Hmmm. Is there a correlation between the total volume of the bottle and the graduated cylinder? Can the length/width be factored in to predict the frequency of resonance? Why is it that every question you answered raises another question in my head? Or in this case three, Haha, thanks again!
Thank you so much for making these. I always feel like I come away with a at least basic understanding of something I couldn't grasp before. You explain things very well. =)
Most people get overwhelmed because they don't know the basic formula for where their numbers come from-oh, I remember you mentioned 1/4. The formula can be asked about in ChatGPT or found in a book, for example: L=(2n−1)×wavelength/4 n is the level of the tone
Really great video.Please keep up the good work.Now,I have a doubt that at 4:38 the tuning fork resonates 2-3 times with the cylinder with decreasing amount of fluid.How is that possible?I know that the tube can have several different frequencies but I think the tuning fork has only a single particular frequency so how can it resonate with all the different frequencies ,as I have read that resonance only occurs between "similar" frequencies?
TUNING fork have a fixed frequency. as the level of water decreases the length of the pipe increases the frequency decreases. In a standing wave of closed pipe odd multiples of the fundamental frequency gives the next frequencies which can resonate with the tuning fork as the length of the pipe valued is different in each resonance. so the tuning fork is not responsible for numerous resonance, the increasing length of the pipe makes it behave like different pipes of odd harmonics
Crazy how electromagnetic waves behave very similar. We can use “tubes” of quarter wave length and see the same resonant effect if the end is closed with a conductor. But if the end is opened then the resonant frequency is half wave length. Just like sound in this video!!! I actually use this at work everyday.
At 1:30 how do we know there aren't any other nodes/antinodes inside the tube? Why wouldn't it be a node-antinode-node-antinode distance, in which case the tube's length would equal 3/4 of the wavelenght? I know that then it's a higher harmonic but the equation then changes completely and we get a frequency that's triple its original one.
Great video! However, could you give an explanation on why a node exists in the middle of the double-open pipe? Or: why aren't the gas molecules all move in unison back and forth along the pipe? Thanks!
I don't know about the gas molecule part. But for an open ended tube at the ends you'd have anti nodes since max displacement occurs. And a node can be found exactly half way between two anti nodes thus in the middle of the double open pipe
approximately before the year 1815 the brass trumpet had no valves. could the physics you are explaining result in designing a superior trumpet of that pre-1815 type? We know obviously that trial-and-error could be used to find a proper trumpet tube length (and we know that the primary note and also the harmonics) are keyed to the fairly precise length...Ultimately I am asking do you think the phyics (a la math) is really key to design of a superior or more perfect trumpet? (but what is "perfect"....could be output power or could be frequency precision [ in-tune or out-of-tune] I would suppose).
I wish I had found your videos long ago. I am a Physics teacher too. I am wondering how you set up your class so that every kids has the inquiry opportunity which is hard to manage. How many kids do you have per class and do you ask the students do the experiment by themselves or what? Thank you.
The magic word is "Stations." You want perhaps as many as 5 experiments set up in your classroom. The students can rotate from table to table trying out the experiments. Get them to put their hands-on the experiment. Even in this video, each experiment can be a station. I know it is hard, but try to eventually have a hands-on activity every day.
hi James, thanks for this interesting film. My students tried to calculate the groundfrequency of a soda bottle yesterday, just by measuring the length of the bottle and using 340m/s for the speed of the air. They found a frequency of app 410Hz. When they blew on the bottle, they found a frequency of app 250Hz using their mobil phones and Phyphox. Using 250Hz the bottle resonated, not wit 410Hz. Can you explain this difference? Thanks !!
Yes, the bottle is not a tube. There is extra width which increases the effective length. The formula I use is only for long thin tubes, in fact it is an approximation for 1D sound waves. The worst bottle would be a perfect sphere, which is known as a helmholtz resonator. Most bottles will not meet the tube approximation, which itself has some problems.
Dear Prof., I have a mix up in my terminology, I think you can clear things up. I did the following experiment: I have air flowing through a straight pipe. Pressure ratio between outlet and inlet is lower than the critical pressure ratio, which suggests flow velocity at the outlet is close to the speed of sound. I have recorded the sound of this process and analyzed the frequency spectrum. Suprisingly for me (but maybe not for you), the dominant frequencies are in a integer ratio to one another. So this would imply a standing wave behaviour.. but can it be called that? The air is moving at a great speed through the pipe after all. I search on the web for explanation, of little avail. Literature containing a mathematical approach would be greaty appreciated. Take care, love your videos.
does anyone know what the name of the music he used at the beginning for his intro? it sounds really nice and i want to know the name so i can find it elsewhere 😭
I tried do determine the sound speed in my room using your way. It came out to be about 320 m/s, with a constant frequency of 696 Hz and wavelength about 0.46 m..... Can it be somehow correct?? Btw it's cold here ( below 20° C)
One thing you didn't mention it when we fill a bottle(or a tube in this case) like at 4:28 the frequency of sound coming increases as the length of air in the tube is decreasing so the wavelength decreases resulting in increased frequency!!
I have tried a lot but failed to make a PVC flute of 6 holes closed at one end with a rubber cork...sir Can you help me anyhow to find the distance between cork, blow hole and the figure holes???....please
i have a doubt sir , that shouldn't the tuning fork be placed like 90 degrees rotated about axis ,like the fork is vertical and not face down ,the disturbance cause by the fork is not face down but along the tuning fork. pls clarify.the theory is very well explained by u sir :-)
Both 90 degrees and zero degrees rotation will work. However, 45 degrees rotation will be silent. Try this by holding a fork to your ear and listening.
Nice job Just one issue You cannot assume (1:29) the node to anti node distance to be one quarter of the wavelength, it can be three quarters or even five quarters.
