Standing Wave Demo: Organ Pipes

This is a demonstration of standing waves in organ pipes of different lengths, with both ends open and with one end closed.

This demonstration was created at Utah State University by Professor Boyd F. Edwards, assisted by James Coburn (demonstration specialist), David Evans (videography), and Rebecca Whitney (closed captions), with support from Jan Sojka, Physics Department Head, and Robert Wagner, Executive Vice Provost and Dean of Academic and Instructional Services.

[atifhossain]

🔥🔥🔥 best physics demo teacher I've ever found on internet

[arjunt.]

Finally understood 🙄👍👍👍 awesome explanation and experiment

[jubtech]

Beautifully, musically explained, Sir

[S.A.Shaker]

Amazing sir thanks to you now I have finally understood stationary waves in air columns great job sir

[jesterhernandez]

Thank you for all these videos. I am retired and going back to school and I feel high school cheated me out of all this fun that creates curiosity.

[shriyasachdeva]

your demos are always amazing !!!!
you explain so beautifully

[parvathisurineni]

very useful and clearly understood...
thank you

[yeety]

This is a clever way to make pipes for the pedal division on a small organ where space/money is limited. A small organ will usually have just one stop in the pedal division, a 16 foot Bourdon (French for bumblebee!), of which the pipes are typically made of wood and are stopped (closed) at one end. The '16 foot' actually refers to the 'speaking length' of the pipe, ie. the pitch that would be heard on a specific note of an open pipe of said length, but the pipe in this case is actually 8 foot long. This means you can get the sound of a 16 foot pipe using only an 8 foot pipe, saving space and money. The sound created is a nice bass sound that reinforces the fundementals and minimises overtones, however those can be reinforced too by coupling the manuals to the pedals.

Also, if space is even more limited, for example an organ that could fit in a standard house(!!), an organ could be built using 4 foot stopped pipe to create what is usually referred to as an 8 foot Gedackt (German for covered) which again creates the 8 foot sound from a stopped 4 foot pipe, it is again strong in fundementals and lacking in overtones and creates a very dull sound but works well with a 4 foot principal (open metal pipe) which would be the same physical length but create a sound an octave higher, reinforcing the fundementals

[YashKumar-odqr]

f=nv/2l for open pipe, f=(2n-1)v/4l for closed pipe

[nikhilguleria]

That's A Very Clear Explanation Thanks Sir👌

[TrystansWorkbench]

I now understand why the recorders we played at school sounded so awful. We were blowing too hard.

[Offshoreorganbuilder]

I had completely forgotten watching this video, and seeing it again I notice a basic error in the explanation:
The pipes shown are *not* open at both ends. The end closest to the mouth is closed, with only the fine slot through which the air travels as the only communication between this lower end and the main body of the pipe. The opening which is pointed to is there to allow air to flow into the 'throat', or chamber at that end. From this chamber, the air passes through the slot.

[tetraederzufrequenz]

Fantastic explanation.


I have a question :

Can a jammer be bypassed by a Faraday cage?

[rahulnayak]

Sir, can you tell whether there will be any change in tone/volume of an organ pipe had the cross been circular with same inner volume?

[miguelcampos]

An explanation as to WHY the pitch changes by an octave when you stop the end would have been nice.

I suspect it has to do with how the waves are reflected in each case -- in-phase vs inverted.

[zyanharris]

I wanna work with you ... because I love physics I understand it very good ...

[hooseinz]

Hi doctor, I am a PhD student and I am working on the stationary wave thermoacoustic engine. Is it possible that I can put your name as an advisor professor for my doctoral thesis?
Thank you

[bg]

I thought organ pipe would be made out of some organ but I was wrong:(
But nice explanation!

[DaylightRobberyCA]

What if cross-sectional area of the pipe was held constant as we scaled the pipe with length as the variable?

[mattnbin]

I think he has mistaken the term "open". Flutes are only open at one end. Organ pipes are only open at one end and sometimes stopped at the end as he demonstrated. His description of the pipe being open at both ends is incorrect. The air inlet is not considered "open". The mouthpiece on a flute is not considered "open". The mouthpiece end of a flute is stopped. Both flutes and clarinets have open ends. The clarinet is different from a flute as it is a reed instrument and can play lower due to harmonics from the configuration of the vibration of the large reed in a "half length" resonator. This trick is sometimes employed in the reed stops in pipe organs to get an octave lower sound from smaller reed pipes resonators.