🚀 go-pugleaf

Hakki_Kocabas@kcbbs.gen.nz (Hakki Kocabas) writes:

>> For example, electrons were there much before quantum mechanics  
>> (at least 30 years before) when they were observed in Braun tubes  
>> and similar devices. By the way, your TV and your terminal  
>  
>Whose electrons ?!  
>  
>> (except if LCD) is a Braun tube, and a  
>> ray of electrons produces the image. No quantum mechanics is  
>> necessary to observe this fact ... :-)  
>  
>WoW !  
>So it is a fact that my CRT emits electrons, is that right ?  
>but fact according to what theory ? How can I prove that  
>my CRT emits electrons, according to what theory ?  
>  

Electrons are a good counterexample to your idea. They were
discovered by chance, when people were playing around with
vacuum tubes with a little gas in them, and high voltage.

I guess you have seen electron rays in high school, where you can
see the nice blue colour (blue if the rest gas is air, as usual)
emitted by the ray inside the tube, when you look at it from the side.

Electrons were discovered like this, noting a coloured ray 
in a vacuum tube. No theory preceded the observation. 
You can say that you need a theory of what a colour is, and of what
glas is, but we can leave this for a later thread ... :-)

In high schools they show this experiment in the same way, because 
it shows that by putting a power supply to to pieces of metal in a vacuum, 
you get a beam of something. This something is called "electron".

Later, you can start to measure the mass of it (yes, you need the concept
of mass to do that), the charge (idem) etc.

This fortuitious observation was the reason we say (and you too)
that electron's were *discovered*, and not *invented* or *constructed*.


			Christoph Schiller