Power from thin air

[Xena E]

So the investors in this case: that video shows two guys talking, a black guy who is interviewing a white guy, who seems to be the spokesperson for a group of investors. Therefore not likely a gang using stolen funds but probably bona fide investors.

But... these will be private investors, and organisations making one off investments.

Fund managers at large institutions wouldn't be this involved and certainly wouldn't make themselves known to be have been scammed.

This part seems set up. Make the white guy look the dumb arse but get the point across?

Professional fund managers would have investors money spread across hundreds or thousands of individual 'opportunities' so that individual failures slightly reduce the dividends, not cause actual overall loss.

This isn't a stock market crash situation. It's just a scammer using religion and racial pride to steal from his own people unfortunately: most of the Chikumbutso promotional material on YouTube have positive viewer comments that are based on religious, national, or racial pride, not an understanding of the actual technology involved.

This guy is hailed by his supporters as the "Black Nikola Tesla" this is certainly pretty close to the truth, he's definitely another charlatan for sure.

The mass delusion that there is some undiscovered source of untapped energy in the world that only needs to be harnessed is a common one and will not be going away anytime soon.

X

[SteveThackery]

This guy is hailed by his supporters as the "Black Nikola Tesla" this is certainly pretty close to the truth, he's definitely another charlatan for sure.

How refreshing it is to see someone else who thinks Tesla was a charlatan. To be fair, I think he was both an impressive inventor and a charlatan - the two are absolutely not mutually exclusive. Also, some of his claims appear to be sincere but reflect a strange lack of understanding.

For example, his idea that stimulating a large structure such as a building at its resonant frequency will cause vibrations to build in amplitude until the whole thing collapses is just nonsense. He failed to appreciate that complicated structures have numerous "resonant" frequencies in a pattern as complex as the structure itself. Also, he didn't seem to understand the concept of damping: that energy is lost to heat and sound, preventing the mechanical vibrations building up beyond a certain level.

How wonderful (and dangerous) it would be if Tesla's claim was true: that you could demolish a building simply by strapping a device the size of a shoe box to it and connecting it to a signal generator. Think of it: explosives-free demolition. I wonder why it never caught on.

So: visionary, inventor, charlatan, Dunning-Kruger victim.

Sorry! Off-topic. 

[themadhippy]

How wonderful (and dangerous) it would be if Tesla's claim was true: that you could demolish a building simply by strapping a device the size of a shoe box to it and connecting it to a signal generator. Think of it: explosives-free demolition. I wonder why it never caught on.

But its true man, a secret agency were experimental with device based on teslas  work in a central new york tower block back in 2001

[Bud]

According to Joshua 6:1–27, the walls of Jericho fell after the Israelites marched around the city walls once a day for six days, seven times on the seventh day, with the priests blowing their horns daily and the people shouting on the last day.

Soirce: Wikipedia https://en.wikipedia.org/wiki/Fall_of_Jericho
 

[TimFox]

This guy is hailed by his supporters as the "Black Nikola Tesla" this is certainly pretty close to the truth, he's definitely another charlatan for sure.

How refreshing it is to see someone else who thinks Tesla was a charlatan. To be fair, I think he was both an impressive inventor and a charlatan - the two are absolutely not mutually exclusive. Also, some of his claims appear to be sincere but reflect a strange lack of understanding.

For example, his idea that stimulating a large structure such as a building at its resonant frequency will cause vibrations to build in amplitude until the whole thing collapses is just nonsense. He failed to appreciate that complicated structures have numerous "resonant" frequencies in a pattern as complex as the structure itself. Also, he didn't seem to understand the concept of damping: that energy is lost to heat and sound, preventing the mechanical vibrations building up beyond a certain level.

How wonderful (and dangerous) it would be if Tesla's claim was true: that you could demolish a building simply by strapping a device the size of a shoe box to it and connecting it to a signal generator. Think of it: explosives-free demolition. I wonder why it never caught on.

So: visionary, inventor, charlatan, Dunning-Kruger victim.

Sorry! Off-topic. 

I recommend you read the history of the Tacoma Narrows Bridge collapse of 1940.
A local doomsayer had predicted its failure and filmed the catastrophe as wind-driven resonance destroyed the bridge, which movie became famous.

[Xena E]

Interesting comparison.

(A bridge deck that was an ignorant aerodynamic design being acted upon by a gale force wind, and a madmans shoe box containing some kind of tuned vibrator? Yup exactly the same.)

 

[TimFox]

Military engineers had known for ages that troops should break their marching rhythm before crossing bridges.
In musical instruments, the resonant structures (strings or air columns) can be excited by random noisy forces such as edge tones (wind instruments) or frictional slip-stick (violins), or by impulsive force (plucked strings) to get somewhat continuous oscillations.

[Analog Kid]

In musical instruments, the resonant structures (strings or air columns) can be excited by random noisy forces such as edge tones (wind instruments) or frictional slip-stick (violins), or by impulsive force (plucked strings) to get somewhat continuous oscillations.

I play the violin, am quite familiar with it, and have no frigging idea what you're talking about here.
Pizzicato does not result in any kind of continuous tone, at least not compared with arco (bowing).

"Frictional slip-stick"? I assume here you're referring to how the bow produces sound on a stringed instrument, by alternately sticking to and releasing the string* (due to rosin on the bow). Of course, while that mechanism is "noisy" and random, the tone produced by the instrument is not, due to the definite pitch of the string plus the resonance of the body (and especially the top and bottom plates)

* Which means the driving force of the instrument's sound is a triangle or sawtooth wave.

[TimFox]

In musical instruments, the resonant structures (strings or air columns) can be excited by random noisy forces such as edge tones (wind instruments) or frictional slip-stick (violins), or by impulsive force (plucked strings) to get somewhat continuous oscillations.

I play the violin, am quite familiar with it, and have no frigging idea what you're talking about here.
Pizzicato does not result in any kind of continuous tone, at least not compared with arco (bowing).

"Frictional slip-stick"? I assume here you're referring to how the bow produces sound on a stringed instrument, by alternately sticking to and releasing the string* (due to rosin on the bow). Of course, while that mechanism is "noisy" and random, the tone produced by the instrument is not, due to the definite pitch of the string plus the resonance of the body (and especially the top and bottom plates)

* Which means the driving force of the instrument's sound is a triangle or sawtooth wave.

For slip-stick, the driving force is random and not syntonous with the resonant frequency of the string.  The resonance is excited by the noisy waveform and produces the musical note.
Pizzicato obviously produces a far shorter duration of the musical note, as does a plucked harp string.
Arco is a longer duration of the driving force and produces a more continuous note.
An interesting driving force is the "edge tone" as in a recorder or organ pipe.
Musical acoustics is fascinating and there is a large literature of the physical basis for it.

[BrianHG]

Power from thin air was invented back in the 1760s.  Here is an example clock which was literally powered from thin air:

https://en.wikipedia.org/wiki/Cox%27s_timepiece
This one was built in 1864 and still runs to this day...
https://en.wikipedia.org/wiki/Beverly_Clock

More modern example also exist, however, they rely more on temperature change instead of atmospheric pressure change...

https://en.wikipedia.org/wiki/Atmos_clock

[Analog Kid]

An interesting driving force is the "edge tone" as in a recorder or organ pipe.

I had to look that one up.
So "edge tone" is simply the mechanism whereby sound is produced by a stream of air hitting a wedge, as in instruments that use fipples (e.g.,, recorders or some organ pipes); not the same mechanism that drives other wind instruments like reeds, double reeds, side-blown flutes or brass instruments with mouthpieces.

[Xena E]

Military engineers had known for ages that troops should break their marching rhythm before crossing bridges.

Yes, and engineers continue to be ignorant:



However even this resonance was caused by several tonnes of humans naturally falling into step, not a tiny by comparison mass of what can be carried in a shoebox. Tesla never proved it possible, nor will anyone else. A building so affected would have to be designed to be that unstable.

The trifecta is: input energy, resonance, and damping. The damping in a simple structure is its mass, in an electronic resonant circuit it's losses.

Other urban myths on the subject of resonance taken to absurdity, and equally as nonsensical have also been covered.

[TimFox]

An interesting driving force is the "edge tone" as in a recorder or organ pipe.

I had to look that one up.
So "edge tone" is simply the mechanism whereby sound is produced by a stream of air hitting a wedge, as in instruments that use fipples (e.g.,, recorders or some organ pipes); not the same mechanism that drives other wind instruments like reeds, double reeds, side-blown flutes or brass instruments with mouthpieces.

Yes. Brass mouthpieces exploit vibrating lips, while winds exploit vibrating reeds.  Transverse flutes are a different geometry for the edge tone.
Again, the resonant structure (string or air column) determines the pitch, but the driving force need not be a single tone.
If you compare an acoustic guitar to a solid-body electric guitar disconnected from its amplifier, the need for the guitar body, bridge, etc. becomes obvious, to generate a reasonable volume of sound, more than the string itself can project.

[TimFox]

Military engineers had known for ages that troops should break their marching rhythm before crossing bridges.

Yes, and engineers continue to be ignorant:



However even this resonance was caused by several tonnes of humans naturally falling into step, not a tiny by comparison mass of what can be carried in a shoebox. Tesla never proved it possible, nor will anyone else. A building so affected would have to be designed to be that unstable.

The trifecta is: input energy, resonance, and damping. The damping in a simple structure is its mass, in an electronic resonant circuit it's losses.

Other urban myths on the subject of resonance taken to absurdity, and equally as nonsensical have also been covered.

It’s not accurate to say damping is from the mass.
In a forced damped harmonic oscillator, damping results from a retarding force proportional to velocity.
(Automobile shock absorbers are an example.)
This is analogous to the resistance in an L C R resonant circuit.

Another urban myth is getting the entire population of China to jump up and down in synchrony, using radio broadcasts.

[SteveThackery]

I recommend you read the history of the Tacoma Narrows Bridge collapse of 1940.
A local doomsayer had predicted its failure and filmed the catastrophe as wind-driven resonance destroyed the bridge, which movie became famous.

You aren't serious, are you? Have you given any thought to the enormous amount of power available from that gale compared with Tesla's shoe-box sized device?

Of course you can vibrate anything to death with enough power but that wasn't Tesla's claim. He claimed that his "demolisher" was in a small wooden box in the hotel basement.  It was opened after his death and found to contain some sort of measuring device (I can't remember the details).

EDIT: Re. The wibbly-wobbly bridge: there was never any suggestion that the bridge might collapse. It was closed because of the discomfort to the pedestrians (once they got bored with the novelty).

[SteveThackery]

Yes. Brass mouthpieces exploit vibrating lips, while winds exploit vibrating reeds.  Transverse flutes are a different geometry for the edge tone.
Again, the resonant structure (string or air column) determines the pitch, but the driving force need not be a single tone.
If you compare an acoustic guitar to a solid-body electric guitar disconnected from its amplifier, the need for the guitar body, bridge, etc. becomes obvious, to generate a reasonable volume of sound, more than the string itself can project.

I don't get where you are going from this, @TimFox.  The reality of the phenomenon of resonance is evidently well understood by the contributors to this discussion.  Nobody needs to be taught this. The discussion is about whether Tesla's claim to be able to demolish a building using a shoe-box-sized transducer is remotely realistic. And it isn't: the power required to overcome the damping is enormous. Your example of the Tacoma Narrows bridge required the power of a gale force wind.

[TimFox]

I was trying to point out the difference between driving a resonant structure near its resonant frequency and other types of driving force, answering requests for clarification.