seeelectron

See an Electron Lately?

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This is not about seeing an electron, but rather, the notion that seeing something with our eyes is the end-all requirement for the validity of anything. I will show that our human eye, as a light detector, is NOT a very good detector at all in many aspects, and thus, using it as the standard detector to validate anything is utterly irrational.

The motivation for this is that I often see a lot of ignorant statements on PF that either questioned, or dismissed something just because we can’t “see” it. A prime example that often pops up is the claim that we “haven’t seen an electron”.

https://www.physicsforums.com/threads/concept-of-probability-wave.517272/#post-3423528
https://www.physicsforums.com/threads/bifurcation-of-the-mind.156864/page-4#post-1249395
https://www.physicsforums.com/threads/translating-english-into-mathematical-equations.406116/#post-2736393
https://www.physicsforums.com/threads/chicken-or-the-egg.475024/page-2#post-3162734
https://www.physicsforums.com/threads/no-scientist-has-ever-seen-an-electron.460209/
https://www.physicsforums.com/threads/indisputable-proof-that-electrons-exist.145501/

I could go on and on, but you get the idea. So now, I will show that “seeing” is over-rated!

Of course, there are several ways to attack such stupid (yes, STUPID) arguments. The first is the question on what we mean by “seeing”. Often, most people simply meant seeing something with the human eyes. But what exactly does that mean? If these people were to think carefully, it means a series of events that must occur: (i) visible light from some source hits an object; (ii) light from that object travels to our eyes (iii) our eyes then transmit electrical impulses to our brain (iv) we detect that object visually. That, my friends, is what is meant by seeing with our own eyes.

Next, by the above description, it is clear that our eyes can only see electromagnetic radiation, and not only that, it can only see it within the visible spectrum, which isn’t very much. Thus, if something either does not emit EM radiation, or if the radiation is outside of the visible spectrum, we can’t see it! Let’s go back to our friend the electron. It is a charge particle. Our eye cannot “see” it even if it hits our eyeball! But can we still see it? Sure we can! Enter a cloud chamber! When an electron, especially high energy ones, moves through a cloud chamber, it ionizes some of the air/gas/water vapor molecules. This creates a nucleation site for water vapor condensation, leaving a cloud trail in the chamber. There, you have seen an electron. One could also argue that our eyes are not the only “detector” around. We can also use our other senses. We can’t see wind, but we can hear and feel the moving air. We can’t see heat/IR, but we can certainly feel it on our skin. Our eyes is only ONE of the “detector” that came with our bodies.sensitivity of the human eye over a range of frequency

And speaking of the human eyes as detectors, anyone who has done anything with detection instruments can tell you that the eyes is a very bad detector in many cases. Sure, it has a very high spatial resolution, but man, it sucks everywhere else. For example, look at this figure that shows the sensitivity of the human eye over a range of frequency and also its response sensitivity.

 

Compare to other devices, the human eye has 2 very clear shortcomings: (i) the range of wavelength it is responsive to is extremely small; and (ii) its sensitivity (i.e. quantum efficiency, or QE) is quite low. It has a peak QE of ~1% at around 550 nm. What this means is that out of 100 photons that come in, it can detect, on average, only 1. Compare the range and QE of Vidicon and CCD and our eye is a very poor light detector! And this is what some people are using as the sole criteria of what’s real and what isn’t? Is this rational?

Next, we will deal with the response time, which will produce the time resolution, of the human eye. We all know that when we go see a movie, it is nothing more than a series of still-image frames, moving past us fast enough that we do not see its motion, but rather see the image as being continuous. Standard movie frames (at least till all the new advancements in movie projection) used to go at 24 frames per second (FPS). This translates to 0.04 second per frame. We also know that the human visual system holds an image for about 0.02 second. It means that anything that comes into our visual system faster than 0.02 second will not be perceived as being distinct. So the 0.02-0.04 second is roughly the time resolution of the human eye.

Now, compare this to other devices. I’ve listed before some typical photocathodes used in accelerators. Note the time responses for the various types of photocathodes. The worst of these are in nanoseconds. This is still order of magnitudes shorter than the human eye! One example is GaAs, which is a common photocathode use in both accelerators and photodetectors. On Pg. 25 of this presentation, one can see measurement of the time response. The full-width-at-half-maximum of this photocathode is of the order of picoseconds!

So the human eye is not only a bad detector in terms of its bandwidth range and also in terms of sensitivity, it is also a very SLOW detector and can’t separate a series of event occurring faster than 0.02 second!

As with many things that a lot of people spew without thinking, the debunking of such things often are quite simple IF one has a little bit of knowledge, and the the ability to analyze the situation. Analyze what it means by “seeing”, and then analyze the “detector” that is being use as the criteria. And apply such techniques to the pile of manure that one often hears in the media from politicians, etc., assuming you have such patience. If you are using “seeing” as your sole criteria to accept the validity of something, then you need to seriously examine this “detector” that you hold so highly, because it is a very poor detector!

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PhD Physics

Accelerator physics, photocathodes, field-enhancement. tunneling spectroscopy, superconductivity

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  1. glaucousNoise
    glaucousNoise says:

    There's some important philosophy here that's being ignored though. I can't recall the source of the quote or the quote itself, but there's a quote of the form:"We can build a model of how the hands of a watch tick and make predictions, but we can never open the watch to understand its inner workings"or something like that. It's very important, I think, to not make a terrible philosophical mistake engaged in by particle physicists in particular, and confuse our models with reality. So the question "Is an electron real? No one has ever 'seen' one" may be posed stupidly if the standard of existence is human eyesight, but it arises from something very important, which is curiosity about what the dividing line between what is an objective, external reality and what is not.An electron, in many ways, is a complex, sometimes inconsistent network of mathematical and qualitative assertions, and the fact that we cannot see it raises genuinely important questions about what the difference is between human models and objective reality, since ordinary people don't often ask such questions about, say, Zebras.

  2. Smattering
    Smattering says:

    All right. But when they complain that nobody has ever seen an electron, they are not claiming that their eyes are superior detectors. It's more like an allegory for the fact that the subject is too abstract for them.

  3. 256bits
    256bits says:

    QuoteAnd apply such techniques to the pile of manure that one often hears in the media from politicians, etc., UnquoteI have the feeling that even if your prose was "required reading", there still would be a segment of the population that  would remain unconvinced, and stubbornly comment  "But still ….. "

  4. ZapperZ
    ZapperZ says:

    There’s some important philosophy here that’s being ignored though.

    Important to whom?

    I can’t recall the source of the quote or the quote itself, but there’s a quote of the form:

    “We can build a model of how the hands of a watch tick and make predictions, but we can never open the watch to understand its inner workings”

    or something like that. It’s very important, I think, to not make a terrible philosophical mistake engaged in by particle physicists in particular, and confuse our models with reality. So the question “Is an electron real? No one has ever ‘seen’ one” may be posed stupidly if the standard of existence is human eyesight, but it arises from something very important, which is curiosity about what the dividing line between what is an objective, external reality and what is not.

    But you are making an a priori assumption that there IS “an objective, external reality” that is somehow inaccessible to us. How would you even know such a thing exist? You are basing your argument on a unicorn. This is the worst part of “philosophy” and why such a topic isn’t allowed in this forum.

    An electron, in many ways, is a complex, sometimes inconsistent network of mathematical and qualitative assertions,

    Say what? You stated this without any kind of justification or evidence. Show me where it is “sometimes inconsistent network of mathematical and qualitative assertions”.

    since ordinary people don’t often ask such questions about, say, Zebras.

    They should, because their observation of zebras abide by the SAME set of rules. And in fact, I would assert that there are MORE definitive and quantitative observation of electrons than there are zebras. I can’t see zebras when it is dark, but I can still detect electrons with my detector!

    But beyond all this, in your haste to sell your unobserved reality, you completely missed the whole point of the article. It has nothing to do with objective reality that you are so in love with. Rather, it has everything to do with how bad your eyes are as a detector. Is this something you do not agree with despite all of the evidence that I had presented?

    Zz.

  5. ZapperZ
    ZapperZ says:

    All right. But when they complain that nobody has ever seen an electron, they are not claiming that their eyes are superior detectors. It’s more like an allegory for the fact that the subject is too abstract for them.

    “.. an allegory for the fact that the subject is too abstract for them… ” What does that even mean?!

    Is it like claiming ignorance of a law after you’ve broken it? “Sorry officer, I didn’t know I was breaking the law!” How well does that go?

    Just because “they” didn’t understand it doesn’t make it abstract and unobservable.

    Zz.

  6. sophiecentaur
    sophiecentaur says:

    ”.. an allegory for the fact that the subject is too abstract for them… ” What does that even mean?!

    Is it like claiming ignorance of a law after you’ve broken it? “Sorry officer, I didn’t know I was breaking the law!” How well does that go?

    Just because “they” didn’t understand it doesn’t make it abstract and unobservable.

    Zz.

    Actually I see where he’s coming from. He is pointing out that some people demand a concrete form of evidence of things before they are prepared to acknowledge its existence or even that ‘scientists’ could understand those things. That attitude makes me smile when people post ideas like that, using electrons all the time for their communication.
    PS I was looking for a better word than “allegory” but couldn’t come up with one. I assume you agree with the meat of his comment – but I found your post equally abstruse, I’m afraid. :smile:

  7. ZapperZ
    ZapperZ says:

    Actually I see where he’s coming from. He is pointing out that some people demand a concrete form of evidence of things before they are prepared to acknowledge its existence or even that ‘scientists’ could understand those things. That attitude makes me smile when people post ideas like that, using electrons all the time for their communication.
    PS I was looking for a better word than “allegory” but couldn’t come up with one. I assume you agree with the meat of his comment – but I found your post equally abstruse, I’m afraid. :smile:

    But that is the whole point of the article. A “concrete form of evidence”, for most people, implies seeing it with their own eyes. My argument here is that your eyes that you’ve been using as the standard bearer for detection are very poor, and worse than many detectors that we have!

    However, if people are demanding they should be able to see an electron with their eyes because electrons are something “too abstract” for them, then the issue here isn’t the detection, but the understanding of what electrons are! After all, physicists won’t argue that electrons do not exist simply because they can’t see them with their eyes. So just because something appears abstract to you, it doesn’t mean that you need to see it for you to accept that it exists. After all, brain surgery is “abstract” to me. Do I dismiss it simply because I don’t understand it? Do I really need to see brain surgery in action with my own eyes for me to accept that it can be done?

    Zz.

  8. sophiecentaur
    sophiecentaur says:

    A “concrete form of evidence”, for most people, implies seeing it with their own eyes.

    But, of course, they don’t [U]always[/U] want to ‘see’ something with their own eyes. The typical person we are discussing is quite prepared to believe all sorts of ‘evidence’, even when presented third hand, on the grounds that they ‘could understand that’ and the information reinforces their prejudices. The daft arguments for and against medical treatments are an example.
    I guess we’re just saying that people are fallible and we happen to be taking offense about their attitude, particulalry when it happens to go against [U]our[/U] special ‘loves’. So we are actually being no more rational than the others. (You just can’t win).

  9. Smattering
    Smattering says:

    ”.. an allegory for the fact that the subject is too abstract for them… ” What does that even mean?!

    It means that they are lacking the required background knowledge (or in some cases even the cognitive capability) to verify the presented chain of evidence, and they are not willing to just believe what they are told by someone who claims that he can.

    Just because “they” didn’t understand it doesn’t make it abstract and unobservable.

    The problem is that if you are unable to verify a presented chain of evidence yourself, then you have to believe in the judgement of others who claim that they can. With respect to natural sciences that might not be an issue for you, but there might be other areas where even you are lost.

    Let’s assume for example, that some law expert presents you a chain of legal arguments that you are completely unable to verify on your own. Then you might say something like “On the high seas and before the court, one’s fate is in Gods hand”. And this is actually the same category of statement as “Nobody has ever seen an electron”. It just means: I am unable to verify this myself. So either I just believe what the so-called experts tell me, or I have to take an agnostic position.

  10. ZapperZ
    ZapperZ says:

    It means that they are lacking the required background knowledge (or in some cases even the cognitive capability) to verify the presented chain of evidence, and they are not willing to just believe what they are told by someone who claims that he can.

    The problem is that if you are unable to verify a presented chain of evidence yourself, then you have to believe in the judgement of others who claim that they can. With respect to natural sciences that might not be an issue for you, but there might be other areas where even you are lost.

    Let’s assume for example, that some law expert presents you a chain of legal arguments that you are completely unable to verify on your own. Then you might say something like “On the high seas and before the court, one’s fate is in Gods hand”. And this is actually the same category of statement as “Nobody has ever seen an electron”. It just means: I am unable to verify this myself. So either I just believe what the so-called experts tell me, or I have to take an agnostic position.

    But even you have to admit that this is not what the article was about. It is about the use of one’s eyes as the sole determination of what “exists” and what doesn’t! If you insist that it is justifiable that people who do not understand the physics involved with electrons, and that the ONLY way that they can be convinced that electrons exist is by seeing them with their own eyes (i.e. using a very poor detector), then we have nothing more to talk about here.

    Zz.

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