Joule Thief 101

[Pirate88179]

Please go ahead Brad, I would like you to tell me what you think is wrong with my two answers.

Here they are:

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.

Stiffness only refers to the resisting of a movement in a given direction.

Elasticity refers to both the resistance to the movement AND the returning to the condition/configuration prior to being moved as seen in a resonating glass.  They are NOT synonymous engineering terms. 

Other than that, I don't see any other real errors here.

Bill

[tinman]

Stiffness only refers to the resisting of a movement in a given direction.

Elasticity refers to both the resistance to the movement AND the returning to the condition/configuration prior to being moved as seen in a resonating glass.  They are NOT synonymous engineering terms. 

Other than that, I don't see any other real errors here.

Bill

all of the energy is stored as kinetic energy in the form of a moving mass ?

If so,then where dose the energy come from that creates the sound ?

[MileHigh]

Stiffness only refers to the resisting of a movement in a given direction.

Elasticity refers to both the resistance to the movement AND the returning to the condition/configuration prior to being moved as seen in a resonating glass.  They are NOT synonymous engineering terms. 

Other than that, I don't see any other real errors here.

Bill

No, that's not true.  I asked that the questions be answered in simple terms.  Are you trying to tell me that you can't talk about the stiffness of a spring?  Are you telling me that you have never used that term in your life when talking about a spring?  Are we all in remedial English class now?

Here, from a spring manufacturer:

http://www.acxesspring.com/spring-stiffness-calculator.html

There are many spring calculators around the internet but none like Spring Creator. This spring stiffness calculator will calculate all of the values required to determine whether the spring will be stiff enough to meet its requirements. The stiffness of your spring depends on the proportion of each spring dimension with all the others. This is where spring index and space between the coils (pitch) comes in. The examples shown below the calculator will explain why your spring is either too stiff or not stiff enough.

A Dummies link:

http://www.dummies.com/how-to/content/how-to-calculate-a-spring-constant-using-hookes-la.html

Hooke's law gives the force a spring exerts on an object attached to it with the following equation:

F = –kx

where the minus sign shows that this force is in the opposite direction of the force that's stretching or compressing the spring. (k is called the spring constant, which measures how stiff and strong the spring is. x is the distance the spring is stretched or compressed away from its equilibrium or rest position.)

I flat-out refuse to get into another nonsensical debate on this thread.

MileHigh

[wattsup]

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. 

Wrong. The glass never stops moving. At a point where the glass is at its maximum, there is no maximum because that maximum effect is transferred elsewhere on the glass rim. There is no stopping. This is not like a spring.

You are treating this like it is a pulsed coil. This is not a pulsed coil. It is a closed loop that generates it own internal harmonics and there is no stopping anything during the resonance, just the intensity of the resonance will fluctuate but never stop. Why because the energy used to resonate the glass does not stop as well.

This is just junk though. Again unrelated to coils, cores and the like.

wattsup

[poynt99]

Wrong. The glass never stops moving. At a point where the glass is at its maximum, there is no maximum because that maximum effect is transferred elsewhere on the glass rim. There is no stopping. This is not like a spring.

You are treating this like it is a pulsed coil. This is not a pulsed coil. It is a closed loop that generates it own internal harmonics and there is no stopping anything during the resonance, just the intensity of the resonance will fluctuate but never stop. Why because the energy used to resonate the glass does not stop as well.

This is just junk though. Again unrelated to coils, cores and the like.

wattsup

You may wish to rethink your response. Clearly the glass resonates in a uniform fashion, and it does experience a maximum deformation point where it stops before being deformed in the other two adjacent quadrants.

https://www.youtube.com/watch?v=BE827gwnnk4