> a year to fire people even when they don’t show up
In what country? I just checked, in France it's 15 days. The employer can ask to be paid the notice period, and the employee won't get unemployment benefits.
- If the interference pattern was explained by diffraction by a semi-infinite plane, why don't I see it when using only one finger? I only see a blurry shadow. The second finger is needed to make the pattern appear.
- All formulas that are used compute the light intensity projected on a screen. In the actual experiment, we're looking at the slit through a lens (our eye or a camera). That's not the same thing.
- The fact that this is white light interference is handwaved away. To model it correctly, you'd need to compute what happens at each wavelength, then integrate the resulting spectrum multiplied by CIE's x, y z functions at each point, and finally do a bunch of math to bring that in the sRGB color space if you want to display the model's result on a screen.
[Too much math before my first coffee in the morning.
Anyway, the harder I try to write a rebuttal, the harder it gets. Now, assuming a .1mm gap (1/32 inches) and 500nm visible light, the article translates to something like ~A 200 wavelengths single slit can be approximated as two semi-infinite screens~ that makes a lot of sense.
But I may be missing something.]
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Back to your questions:
> - If the interference pattern was explained by diffraction by a semi-infinite plane, why don't I see it when using only one finger? I only see a blurry shadow. The second finger is needed to make the pattern appear.
I got the best results with a led lamp on the wall of my kitchen. It's a 5x5 inches square, with a white translucent plastic and a metallic frame that hides a led strip and can be bought in any electricity store near my home. I was standing like 10 foots away, in a slightly dark area (or use the other hand to cover the eyes and fingers).
I almost put my finger like 3 inches away from my eyes, I close the fingers until I see the pattern. Then I open them slightly and I see a phantom line around my finger that does not disappear when they are far away from each other. If I look very carefully, I see a second phantom line.
- All formulas that are used compute the light intensity projected on a screen. In the actual experiment, we're looking at the slit through a lens (our eye or a camera). That's not the same thing.
A standard trick is to use a lens and a screen at the focus distance instead of a screen at infinity. This is similar to the eye. The lens in the eye will have a different adjustment to make a clear image of the eye, so it will not be exactly equivalent. But it's close enough. I'd not worry too much about this part.
> - The fact that this is white light interference is handwaved away. To model it correctly, you'd need to compute what happens at each wavelength, then integrate the resulting spectrum multiplied by CIE's x, y z functions at each point, and finally do a bunch of math to bring that in the sRGB color space if you want to display the model's result on a screen.
To get a nice rainbow interference pattern, you probably need a almost puntual source of light. A diffuse source will make a blurred rainbow that is impossible to notice. But I need a diffuse source like the lamp in my kitchen to notice the dark lines because they are too weak.
White leds use phosphorus to get the full spectrum, I'd try with a lamp with leds of color that are almost monochromatic. I'd try with red and blue to maximize the distance of the interference lines, but I'm not sure if the blue leds use phosphorus too. Perhaps red and green is better for this. (Perhaps a computer screen with Painbrush filled with #FF00FF is a good alternative.)
Blue LED don't use phosphorous, their spectrum is a few nm wide, just like other colors. I wouldn't bet on the spectral quality of a random screen. OLED might be okay, but other technologies use filters in front of a white light, the spectral width will probably be wider.
>-sure, but weirdly the effect has to be wavelength dependent, but there are no color fringes.
I do think you can get colour fringes in some circumstances. Try doing it in a dark room with a bright light coming through a small gap (e.g. between curtains). Like:
IIRC you can get colour fringes between the finger and the top edge of the gap behind it.
EDIT: I just tested it, there is definitely a rainbow spectrum between the finger and the gap. The gap side is blue and the finger side is red. Not sure if this is the same effect as the article though.
Interesting, I can only see the bands when holding my fingers very close to my eye, and _not_ focussing on it. If I hold my fingers far enough to be able to focus, I don't see them. Maybe my eyesight is not good enough. Focussing on a single finger, I see that the border has a green tint to it.
I agree that there's no colour in the fringes, which is unexpected for white light interference.
Changing the PCB for a known-good one: $10 + maybe half an hour of low-skill work.
Changing the failing component: maybe a few minutes, probably a few hours of an electronics engineer that's familiar with the design (plus his expensive tools). He's probably bad at soldering, so you'll need someone else to do that. Then you need to revalidate the board.
It almost never make economical sense to try to repair the board.
If we were provided board and part diagrams it might be worth it because then you don't need an actual engineer or super highly knowledgeable person to waste a few hours of time just to diagnose most problems. But because we lack such diagrams whoever is diagnosing it also has to reverse engineer how it works in their head.
The fact that we tolerate creating waste because it's "economical" is frankly disgusting. The disposal fees for e waste should make it uneconomical to dispose of boards.
Also training techs to repair SMD parts is really easy and cheap, you're grossly overestimating the costs. The real waste comes from boards with designs that can't be repaired so we tolerate a certain yield. For many small devices the yields are shockingly low.
The other thing is that yields are low because of bad designs. If it became uneconomical for you to throw half your boards out then designers would fix their crappy boards with tombstoned jellybean parts because they used shitty footprint libraries. This is a solvable engineering problem and it's gross that it's cheaper to throw shit into a landfill instead of fixing it.
> The fact that we tolerate creating waste because it's "economical" is frankly disgusting.
I don't think anyone here is suggesting we "tolerate" it, but describing the economic incentives that exist.
> The disposal fees for e waste should make it uneconomical to dispose of boards.
I can't think of any number that you could pick that wouldn't either be ineffective, or cause unintended effects. At $10, that's a drop in the bucket compared to labor costs of component level repair. At $100, you're going to see the local lake filled with obsolete cell phones, which is even worse than them being in a landfill.
To get single photons, you just need to stack up enough stained glass infront of a light source. That's been acheivable for aeons (the photon will go through at random time though).
The difficult part is single photon _detectors_, they're the key technology to explore the single-photon version of Young's experiment (which originally showed that light has wave-like properties).
The first working transistor was centimeter-scale, now billions of them fit in that space.
The first useful internal combustion engines were room-sized, now they fit on a moped.
The truck-sized hole in your argument is talking about "the smallest test". First discoveries/demonstrations of interesting phenomenons don't typically happen at the smallest scale (why would they?).
The first working transistors and engines were of the size which happened to be most convenient to work with. They could then be shrunk because fundamental physical limits to their size were far below human scale. Their inventors were neither constrained by nor interested in those fundamental physical limits. They were inventors, not scientists.
In contrast, a particle accelerator like the LHC is designed from the outset to explore physics at a given energy scale at the lowest possible cost. Shrink it any further and it will no longer work. Despite decades of attempts to come up with alternative designs, when time comes to draw up plans for a successor capable of pushing to even higher energy, it's just more of the same:
100 km/h is slow compared to passenger train (even non-high-speed ones). Depending on how packed the schedule is, it might not be possible to analyse track during the day without causing backups.
A million alternatives is peanuts. Restricting the search space to text files with 37 possible symbols (letters, numbers, space), a million different files can be generated with just 4 symbols.
A trillion is 8 symbols. You still haven't reached the end of your first import statement.
I just took a random source file on my computer. It has about 8000 characters. The number of possible files with 8000 characters has 12500 digits.
At this point, restricting the search space to syntactically valid programs (how do you even randomly generate that?) won't make a difference.
I double checked because these were not the prices I had in mind.
After looking through the options, I think that's because the designs I did quotations for had 0.2mm holes. This is standard for Eurocircuits, but high precision for JLCPCB.
Note that to get the price you quoted, you'll get lead in your PCB, and vias that are not plated, but plugged with conductive epoxy. Changing that gets you to $14 for 5 boards, which is still way cheaper than Eurocircuits.
I'll keep that in mind for the next PCB I design: keep holes bigger than 0.3mm if possible.
My laptop has one of these ethernet ports that half close when not in use. It doesn't work anymore because someone mistook it for the USB port that's right next to it when distractingly plugging their keyboard in.
I agree with the sentiment, but what stops the government designating annoying people or companies as russian (also see "foreign agent" and "matter of national security")?
Also, am I on the hook because my wife's great-grandfather was russian?
Because my idea is that it wouldn't be the government designating them, but judges. Just like a judge already today has the power to lock you up for life, but only after a lenghty rule of law process.
But the trouble is judges are human, and if the boss of your boss who could shut down your court and turf you out is loudly proclaiming "will nobody rid me of this troublesome Russian"... what lawful ruling will the judge find to appease their master?
The other thing that sprang to mind was the US interning their own citizens in camps. Would you be in favour of internment camps across Europe for all citizens with any Russian heritage, preemptively locking them up in case they might provide succor to The Enemy?
You are making an argument against any kind of rule of law in general. If somebody powerful can say to a judge "will you please sentence this competitor of mine to life in prison" and he complies, that's the same problem. But judges in Western countries are very rarely that corrupt, and thus rule of law functions.
In what country? I just checked, in France it's 15 days. The employer can ask to be paid the notice period, and the employee won't get unemployment benefits.
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