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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  1. Smattering
    Smattering says:

    But even you have to admit that this is not what the article was about.

    Sorry, it was not my intention to bash your article. The article is well-written, and I enjoyed reading it.

    If I was allowed to propose one improvement, it would probably be to put more emphasis on the commonalities between “detecting something with your eyes, ears or sense of touch” and “detecting something with external tools”.

    It is about the use of one’s eyes as the sole determination of what “exists” and what doesn’t!

    I get your point, and you certainly did a great job explaining why external tools can be much better detectors than our natural senses. But for some of the sceptics the challenge might rather be to understand what the process of detecting something with an external tool has in common with the process of detecting something with our natural senses.

    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.

    You are completely right: Our eyes are indeed very poor detectors when compared with a CCD. But we all had much time to get used to our eyes, and we all (at least those of us who can see) have acquired a great part of our knowledge about “the world” by observing it with our eyes. Trust is closely related with familiarness. People are confident that they can judge about a chain of evidence that they can see with their eyes, simply because they are so familiar with this process.

  2. Nugatory
    Nugatory says:

    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.

    That’s not quite right…. In that case your choices are to believe what the experts tell you, or to decline to take any position on the grounds that you haven’t studied the issue yourself. The latter is not an agnostic position – the agnostic position is that the truth is unknowable, so actively denies the possibility that the experts have the answer when the agnostic does not.

    The “No one has seen an electron with their own eyes” argument sets teeth on edge because it ignores this distinction, promoting the arguers lack of knowledge into a universal truth.

  3. sophiecentaur
    sophiecentaur says:

    The word is EVIDENCE. You couldn’t trust your eyes alone, even if you somehow thought you had ‘seen’ an electron. Have you ever ‘seen’ a distant galaxy (except as a photograph)? Have you ever ‘seen’ a tektonic plate moving? Why does the phrase “believe the experts” read as being dismissive? If we didn’t have experts, we would have no medicine, engineering or chemistry; we need to believe them and, when several of them agree and present evidence, that is more than enough to be going on with. On the other hand, when we see Penn and Teller, we don’t actually believe that the little guy’s head has just been cut off.

  4. Smattering
    Smattering says:

    That’s not quite right…. In that case your choices are to believe what the experts tell you, or to decline to take any position on the grounds that you haven’t studied the issue yourself. The latter is not an agnostic position – the agnostic position is that the truth is unknowable, so actively denies the possibility that the experts have the answer when the agnostic does not.

    I always thought that not taking a position is the main point about agnosticism. But if you think that agnosticism refers to a specific motive for not taking a position, then let’s just call it “not taking a position”.

  5. sophiecentaur
    sophiecentaur says:

    I always thought that not taking a position is the main point about agnosticism. But if you think that agnosticism refers to a specific motive for not taking a position, then let’s just call it “not taking a position”.

    That sort of implies equal weighting to the expert view and my uninformed view. How can one hang on to an uninformed view on the off chance that it could possibly be right (the probability being based on ignorance, perhaps). This has been the approach of medical quackery and many people have suffered accordingly.
    Science is agnostic by nature. Science admits to the ever present possibility that, tomorrow, a theory may arrive and turn everything upside down. But you owe it to yourself to to commit to what you have found to be right until there’s some damned good evidence to the contrary.

  6. Smattering
    Smattering says:

    That sort of implies equal weighting to the expert view and my uninformed view. How can one hang on to an uninformed view on the off chance that it could possibly be right (the probability being based on ignorance, perhaps).

    Because there are people who simply have no trust in authority, and who are not willing to accept authority. I am not one of them, so please do not blame the existence of such people on me.

    I also mentioned the alternative which is simply to believe what is claimed by those who are considered experts. But then again, how do you know who has the best expertise? If you are lacking the knowledge to judge on subject yourself, then it seems likely that you are also lacking the knowledge to decide who is competent with respect to that subject. So again, you have to trust the judgement of others.

    At the end, it is all about trust: If you cannot judge yourself, you have to trust the judgements of others.

  7. sophiecentaur
    sophiecentaur says:

    Yes. You have to trust. People often have a problem with that because giving that trust may mean hard work in actually learning some theory rather than some easier, half baked ideas. Imo, that’s often the reason for choosing a model. (It is such a shame to be maths phobic, in particular.)

  8. ZapperZ
    ZapperZ says:

    Because there are people who simply have no trust in authority, and who are not willing to accept authority.

    Then those are the people who live out in the woods, devoid of any contact with civilization. After all, for them to use their cellphones, fly in an airplane, or go to a doctor will all require that they be an expert in Special Relativity, General Relativity, Quantum Mechanics, Medicine, etc… These backwoods, isolated folks are not the one I encountered who asked me if I have “seen” an electron, and they are also not the ones who posted in all those threads that I cited in the article, because that will imply that they have to use some modern electronics and will have to know solid state physics and material science.

    We have ended up with making too many claims and too many characterization of “other” people as strawmen to argue against this. If you are not one of them, don’t speculate on their behalf unless you are willing to defend such a thing. The article points to the fallacy of just your eyes as the final arbiter of what is real and what exists based on the fact that our eyes are very poor and limited detectors.

    Now, this is BEFORE I argue on the fact that our eyes and our “observation” can easily be fooled. We are not only limited by many optical illusions, but what we see has to be processed by our brains, which in itself has its own set of issues. I can point out to you studies in which people swear they saw something that never happened (seeing Bugs Bunny at a Disney theme park) simply via a suggestion. Now, did their eyes actually saw that? But they claim they did, so it is as “real” to them as anything else.

    So now, not only do we have a physical shortcoming in terms of our optical system alone, but we also have a shortcoming in terms of how human being actually decide if he/she actually saw something in how the brain process on what we believe we saw.

    And this is the device that these people will trust in.

    Zz.

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