Wine Glass Questions - Answered

How does a wine glass resonate, what is the mechanism?

The wine glass resonates by cycling energy back and forth between two forms, kinetic energy and potential energy.  The instant when the glass is not deformed, the glass is moving at a maximum velocity and all of the energy is stored as kinetic energy in the form of a moving mass.  The instant when the glass is at its maximum deformation, the glass has stopped moving and all of the energy is stored as potential energy in the form of a compressed spring.  In between these two states, the energy is stored as combination of kinetic energy and potential energy.

How is the resonant frequency of a wine glass determined?

The resonant frequency of a wine glass is determined by a combination of the effective moving mass of the glass and the effective stiffness of the glass interacting with each other.  The higher the effective moving mass of the glass, the lower the resonant frequency.  The higher the effective stiffness the glass, the higher the resonant frequency.

In Other Words:  Rap the glass and it twangs at its natural
resonant frequency.  If that tone isn't satisfactory, partially
fill the glass with wine and rap it again.

Repeat as necessary.

Drink the wine following each trial.

If you have been following along I stated that I will not give any clues to lead people to the correct answer.  It's a no-spoon-feeding zone.  You either get it right or you don't.  I also said that if nobody gets it I will provide the answers next week.

Over the years I have provide a ton of informative explanations so you should take back your words because they are a lie.

Over the years you have provided a lot of words, and occasionally a few pictures or drawings to go along with them. Whether those words and pics can be considered informative explanations or not is purely subjective opinion.
Cheers

Wine Glass Questions - Answered







  The higher the effective moving mass of the glass, the lower the resonant frequency.  The higher the effective stiffness the glass, the higher the resonant frequency.

How does a wine glass resonate, what is the mechanism?--The wine glass resonates by cycling energy back and forth between two forms, kinetic energy and potential energy.

Er-no.
The wine glass will not resonate at all unless it receive's energy from another source.

 

The instant when the glass is not deformed, the glass is moving at a maximum velocity and all of the energy is stored as kinetic energy in the form of a moving mass.

Er-wrong again.
Some of the energy is dissipated as compression waves--  sound waves MH.

 

The instant when the glass is at its maximum deformation,

Already included this bit in one of my explanations--which of course you said was wrong.
Quote post 1696-It resonates due to the deformation and reformation  of the wine glass from it's rest shape,

 

the glass has stopped moving and all of the energy is stored as potential energy in the form of a compressed spring.  In between these two states, the energy is stored as combination of kinetic energy and potential energy.

Nope-im afraid not. Some of the energy is dissipated as compression waves(sound waves),and some is dissipated as vibration through the table or platform the wine glass is sitting on.

How is the resonant frequency of a wine glass determined?
The resonant frequency of a wine glass is determined by a combination of the effective moving mass of the glass and the effective stiffness of the glass interacting with each other.

So you say the resonant frequency is determined by-effective moving mass,and stiffness of the glass.To you this is correct.
I say (post 1696)-The resonant frequency of a wine glass is determined by the shape,size,and structure of the glass,where you effective moving mass !is! the shape and size,and your !stiffness! is determined by the structure of the glass/crystal that the wine glass is made from;

Lol
MH-you really are a comedian some time's

It was a good laugh-if nothing else.


Brad

Tinman, I agree the approaching magnet will give rise, but only to the peak of the positive, at TDC that positive peak then reverses instantly to negative peak ,and as the magnet leaves the negative peak rises back to the zero line.??
Why would the decline of the + peak and the propagation of the negative peak take twice as long when only at TDC?
The only way I can see your sine wave is if the core of the coil is twice as wide as the magnet. This would give time for decline of the positive and the rise of the negative.
Not trying to start an argument  just trying to understand.
artv

Because complete flux linkage from the PM to the core will happen just before TDC,as the magnetic fields will curve toward the steel core of the inductor(generating coil). The flux linkage will also remain at it's maximum slightly after TDC due to this magnetic field curve. Let's just say that we get total flux linkage between the PM and the steel core at 1* BTC and 1* after TDC. This gives us 2* where the magnetic field in the core is not changing in time. As the magnetic field is not changing in time,then there will be no EMF produced across the generating coil--as per faradays law of induction states.

at TDC that positive peak then reverses instantly to negative peak

That simply cannot happen,as can be seen in the AC wave form. You cannot jump from the positive peak of the EMF wave form,to the negative peak of the EMF wave form--you must pass through the 0 volt value first.

Please do not take any notice of MHs messed up timing diagram and associated wave form,as it is incorrect. Faradays law of induction says that it is incorrect. How MH came up with that one--i will never know.

I will put together a test bed,and i will show you in slow motion the wave form that is produced when a magnet passes a coil. I will show from a 10 oclock starting position to a 12 noon finnish,and then from 12 noon to the 2 oclock position,and then a full sweep from 10 oclock to 2 oclock.
We can watch all this in slow motion on my scope.

Will get it done for you ASAP.


Brad

That will be greatly appreciated. Can you do the test with a iron core and just an air core ?
Looking forward to it. Thanks artv

I can do that.

So just to clear things up a bit.
when we use 1 single small magnet with a small field,you will(should see a sharp rise in a positive sine EMF (voltage across the coil)as the magnet approaches the coil,and then a sharp decline to the 0 volt line,as the magnet is stopped at the center of the core. As we move the magnet away from the core of the coil,we should see a sharp rise in EMF across the coil,but with a negative sine. I will set the scope up to show the sine being a positive value when the magnet is approaching the core of the coil,and then a negative sine when the magnet is leaving the core of the coil.

When i remove the stopper,and we do a full sweep from 10 oclock to 2 oclock,we will see a sharp transition from peak positive to peak negative--maybe this is what you were talking about?.
But as you will see,the trace on the scope will show that the EMF dose pass through the 0 volt line on the scope,and that will be the point where the magnet is directly inline with the core of the coil.

We will see this more clearly when i do the motor driven generator test,where the frequency will be much higher.

Test setup already half done.


Brad

It is quite funny that you can keep on and on about that magical question you asked EMJ--keep on badgering him about it time after time,and yet you your self cannot understand the very laws you preach--that being faradays law of induction.

You just had to step in,and say my diagram was wrong--even admitting to being picky. You then modified my diagram to show what !you! think is the correct wave form for the !circled! time- path (in orange) for the magnets start and end position to form that sine wave you drew on the diagram.

I agreed with Bill to keep it civil,and so i will not use the words you keep using.
But every time you have tried to correct me on this thread,and call me all sorts of names under the sun,you have repeatedly fell flat on your face,and i have had to continually correct your mistake's,so as those here will learn from correct information.

I cannot believe after all this time--all your insulting smart ass comments toward other experimenters (mostly EMJ),and all your preaching of the laws you love so much,that you have no idea how to show them on a simple diagram--which you did not even have to draw--i drew it for you,and you scribbled some rubbish on it.
You preach faradays law of induction,but you screw it all up when it's comes to showing it on paper--you just dont understand what you preach,and there for have no right what so ever to judge other people-like EMJ.

Your ass should be made to apologize to EMJ,as you know less than he dose about basic induction.
In fact,i think EMJ would run rings around you in basic transformer induction-even though he dose not agree with what TK and myself say about mu little schematic and question.
The one you have screwed up is as basic as it come's,and you had another epic fail.
 Say sorry to EMJ,and come back when you have learned the basics of induction.

Brad

LOL

You then modified my diagram to show what !you! think is the correct wave form for the !circled! time- path (in orange) for the magnets start and end position to form that sine wave you drew on the diagram.

You are absolutely unbelievable sometimes.  The arrow was circled to remind you that the disk is rotating because your second incorrect diagram showed a zero volt output only.

Your third attempt looks great, and at least you are implicitly admitting your mistakes, but we wouldn't want you to say that lest your brain breaks.

In Other Words:  Rap the glass and it twangs at its natural
resonant frequency.  If that tone isn't satisfactory, partially
fill the glass with wine and rap it again.

Repeat as necessary.

Drink the wine following each trial.

Yes, early in the thread you were bursting with attitude when we started to talk about resonance and getting all riled up.  And lo and behold, now that you see the answer you realize that you were not in fact able to answer the question correctly.  Now that you see the answer you can be a better "resonance researcher."

Dear Brad.

Attached is a screenshot of a " pinched field " waveform past an unloaded coil.

This was done a couple of years ago under the " eye " of T-1000, we were looking at the Leedskalnin generator.

I managed to get a pair of 6 mm ( 1/4" ) square magnets with the N poles facing into a rotor that was spun by hand. Note the tightness despite the very low rotation speed.

Cheers Grum.

Yes Grum
That is the wave form you should see when a single magnet with a tight field is passing an inductor.

Brad