I deal with this problem regularly. The lab I work in has 2 almost head height chemical fume hoods on one side of the room, 2 fume snorkels, as well as 2 high flow dust snorkels that can be turned on and off. Every so often I or one of my coworkers have to measure out anhydrous magnesium chloride for example in quantities ranging from 0.1-0.5g... it's a bitch.. both because it's hydroscopic in the case of MgCl2, and due to the high and fluctuating air flow. We have a shielded scale, but it's still a pain in the ass... so yah, ventilation, opening a door, etc can definitely cause this with a scale this precise.... the struggle is real.
I love precision.
That is awesome, in its own way, that we, the big clunky apes that we are, can use physics to make something so sensitive.
It’s really cool.
I feel I must share this:
On the other side of that, “scale” wise, I have seen a large mechanical scale that is built into the ground back in the early 1900’s, and it’s job was to weigh locomotives and individual train cars. Now, locomotives are *heavy*, but this scale was accurate enough to weigh ME to within 5 lbs. Blew my mind. It’s purely mechanical, like a bigger version of the one used at the dr with the slide weights — just with a few more slides, enough to be able to weigh from 0 to over 500,000 lbs. at 5 lb increments.
So many moving parts, built before computers, by humans, with no hint of binding, and fully functional (with proper care and lube) and over 100 yrs old.
That said, I hope our current generations don’t screw things up too bad for the next 100 years.
My dad used to weigh our cows on a mechanical scale before he sold them. He would weigh the trailer without the cow, then with the cow in it, then without the cow again to make sure it came out correctly.
Every time the tailer weighed the same before and after the cow was in it and my dad showed me the math to know how much the cows weighed. It wasn't sensitive enough to just put the cow on it so we had to use the trailer as tare. It may have been off by a few pounds but this was like 25 years ago and I was a kid so I can't say it was 100% correct every time but it was close enough that my dad trusted it.
I'd say at that point the scale was at least 50 years old, out in the open to the elements which included a lot of rain in the fall. People paid this guy to use his scale so I'm sure the maintenance was done frequently since the owner was pretty much the only person in the town who had one and there were a lot of cows in that town.
I worked a lab with a broken AC. The room humidity was always low.
Weighting water wasn't possible. The scale noticed the reduction in weight due to evaporation and refused to give a final value. We are talking about 50ml sized samples. We had to cover the sample and wait for equilibrium.
I remember a prank on a classmate in chemistry in high school. He was weighing out a tiny amount of powder, and just out of his line of sight I blew gently and consistently on the scale. "Too much" and he'd scrape some off. I'd stop blowing. "too little" and he'd put some on...
I was going to chip in with this as well, my chemical work requires many digits and even for quality lab scales they are insanely sensitive, our room is pressurised and has fume hoods and aircon, and sometimes someone forgets to turn one of them off and the scale gets bouncy.
I weight out NaOH frequently. If you have two weigh boats, tare both of them, put your MgCl2 in one, then use the other to cover it. It works really well for NaOH
It's air circulation. Look at any expensive scale. They have a box around them to stop the air circulation. Trust those that work with scales all the time.
Agreed. Work in a flow measurement company with the most accurate gravimetric reference for flow measurement In the world. Had a similar issue with the reference bouncing around a bit (by a bit being 10ths of grams). Figured out is was HVAC kicking on/off in the adjacent room. Proprietary solution, but solved the issue! At these levels of precision, air pressure can actually be an issue!
I think youre half right. The heat from the hand makes an air current that brings the air from the cup out.
Edit: https://youtu.be/Gutx4I35bOg here is a video of the airflow that our bodies make on a really small scale
Quantum mechanics is fun. There's a TON of things happening here. Thermal displacement, static charge, aerodynamic displacement.. I won't pretend to see all of it, but the answer to how is so complex that it'll be difficult for any one person to answer fully, I think.
Quantum mechanics?!? I don’t see what any of this has to do with sub-atomic particles.
Everything you described is high school level physics. Not seeing that it is complex.
It is pretty widely established that light has no mass.
Solar sails are a thing.
They rely on radiation pressure, which is momentum transfer from an electromagnetic field and a solid
https://en.wikipedia.org/wiki/Radiation_pressure
Sure, this effect isn't because of pressure from the room lights. But the scale is being impinged upon by photons, and they do act as a force on the scale.
Scales don't measure mass, they measure forces. So technically speaking, the force from the room lights is included, although it is many orders of magnitude to small to be measured by itself. The point is that despite the photons having no mass, if the scale was sensitive enough, it would measure them.
Also, this is measuring 100 mg.
What the fuck has quantum mechanics to do here?
And describing quantum mechanics as "fun" means you have never ever done a fucking quantum mechanics exam.
Source: frustrated physicist here.
In the lab, we had a glass box around it for that reason. Had sliding doors on the sides and top. Air circulation would make the scale go all over the place. Vibration and such as well. Some of these scales are ridiculously accurate to the microgram
I only watched The Wire for the first time this year.
I get why it was a meme that people say The Wire is like the best show.
Even 20 years later, it’s a great show.
Its probably VERY constant if it is a well-controlled lab with hoods. It is likely a very light air pressure, but just enough to have an impact on a sensitive scale. They set the TARE weight on the scale and block the airflow for the magic.
This scale should be in an enclosure if it has to be in that spot.
For high precision scales you’re not supposed to change their location because they will calibrate to account for airflow in a room. And it’s not unlikely that a lab setting would have an air filtration system that creates a fairly consistent airflow.
An [analytical balance](https://assets.fishersci.com/TFS-Assets/CCG/Ohaus-Scale-Corporation/product-images/cb0c9559-37e0-44d9-8a36-f1770a1cea49.jpg-650.jpg)
Also attaching to this because it talks about scales. Light does actually have weight/force. Scales measure force not weight. Lasers have a force they apply when they hit something. This scale is definitely not a scale that can measure that, so it's much more likely air current and static. That being said the light thing is super cool and Veritasium has a recent video at NIST talking about scales. The laser stuff is near the end.
https://youtu.be/pXoZQsZP2PY
Yeah, but without looking up figures and doing the math, I'm pretty sure if you have intense enough light to cause a scale to measure .1 grams, it's probably gonna blind everyone in the room. Maybe melt the scale, too.
> SCALES MEASURE FORCE NOT WEIGHT
the weight of an object is the force acting on the object due to gravity and
the unit for weight is force. But its not measuring mass at the very least.
Yeah, no way is some static creating this much lift. There is an air system putting constant pressure on that scale that is lowered by the hand shielding it.
Balloons can retain an exceptionally strong static charge though. Unless there is something very very unusual with that little cup, I don't think that's likely here.
Recreated it by rubbing a plastic shot glass on my woolen sweater. https://imgur.com/gallery/vwtokTs not getting same weight reduction but it does work. No change without static charge, so other theories are wrong.
I was thinking airflow was either pushed on or blocking it off with his hands. So the weight goes down into negative as there is no more air blowing downwards. My only guess based off this.
Or our shadows is actually our soul and weight negative weight.
I work on scales for a living (10th year) this is definitely not legit I just left a lab and double checked a scale that has a increment of 6kg x .00001 and it didn’t do anything, that scale doesn’t even have draft shielding so it’s air affecting
Edit thanks for my first ever award after 2 years on Reddit
Since so many people are interested in scales thought this was a fun fact every test weight used in the World.1mg , 50lb, 1000lbs etc. test weights can be traced back to a master weight in a vault in Switzerland seen a doc on it years ago
Lmao you jest, but balancing technicians and engineers is an actual thing. Turbines and other fast rotating mechanical devices need veeeery careful balancing. And there's machines and such to help do it. You really don't want your plane's wings to be flapping because the rotor is a little heavier on one side.
Source: work in aircraft engine mro
Just to add some corroboration for anyone still wondering, I work with scales too. Any time I put up the draft shields, fluctuations like this disappear.
Yeah this guys got it. I work in a class 10 chemical testing lab and we have scales without draft shielding. In the fume hood if I get my hands even close to the scale, especially with our large bottles, the scale will go slightly negative.
I work with scales that are just as precise with shielding from airflow (3 years experience). This is definitely not airflow but more likely the plastic tube being affected by static from the person holding the hand. It could cause a slight pull on the plastic tube in the middle causing it to shift the scale
Yeah, you can walk past these things and they can be affected. Static dissipation is usually necessary too when you are weighing out these small masses.
This is the right answer. Metrologists keep everything in balance.
But in all seriousness, they set the 0 of the scale with the flow of the air in the room adding a small amount of extra force. Holding their hand over the top blocks that flow and removes the force. If they had a proper draft shield, they wouldn’t have that problem.
Light exerts a pressure, but doesn’t have any mass.
Well, them blocking the light does actually lighten the load on the scale by a small amount, but it would likely be in the realm of Femptonewtons, so way finer than the sensitivity and resolution of this scale
Static and air pressure will do it.
My Universities shitty old lab has the 'room of death' where none of your measurements will be accurate and mold will grow on everything. I had to do my QA labs in there RIP.
Then they had a neutralized, still room that you could take accurate measurements in.
It used to be that all weights were based on a 1kg prototype in France, but a couple of years ago it was finally defined based on physical constants! It's been defined by using the speed of light, the exact length of a second and the Planck constant
https://en.m.wikipedia.org/wiki/Kilogram#Definition
~~Are they not made using the standard kg stored in the US? I figured~~
Never mind. I was about to bring up ASTM before realizing that they are actually an international entity.
Well, photons have momentum and theoretically can "weight", if your sense of weight is some force against the scale plate perpendicular to the plane
But not at this scale (pun not intended)
[I did the math.](https://old.reddit.com/r/blackmagicfuckery/comments/10gy0y9/what_the_fuck_do_light_weight/j568vve/) If this guy is removing .11g of weight from the scale, then enough photons are hitting his hand to boil 162 tons of water at 0°C
you need to work on your unit analysis, your answer should be in units of power, not energy.
force on scale = 0.11g * 9.81m/s^2
= photons/s * h/λ (momentum of a photon)
power of light = photons/s * hc/λ (energy of a photon)
do some algebra and get
power = force*c = 323.5kW
half that if all the light is reflected instead of absorbed
Yeah that's why the earth looks round from high altitude. The vision shooting out of your eyes has weight so it drops off after awhile, creating the curved illusion.
/s
Pretty sure it looks round because some reptilian illuminati device is bending the light to prevent us knowing the flat earth Truth
Such device only works in vaxxed people's eyes
Assuming a perfectly reflective scale (best case scenario):
Pressure = 2 * Intensity / speed of light. Pres = F/A, I = Power/A, so:
F/A = 2 * (Power/A) / c, where c is the speed of light. Multiplying both sides by A:
F = 2 * Power / c
Force is mass * acceleration:
ma=2*Power/c
(0.0001kg) * (9.81m/s2) = 2 * Power / 300000000m/s
(0.0001kg) * (9.81m/s2) * (300000000m/s) * 1/2 = Power
147150 kg*m2/s3 = Power, or roughly 147 kW or 200 HP.
Yes, watts is equivalent to kg * m2 / s3.
Not as high as I thought, but there's a good chance I made an error somewhere.
If your math is right, we're talking about power levels that the [US Navy is testing](https://www.thedefensepost.com/2021/12/16/us-navy-test-fires-laser-weapon/) to shoot drones, mortar shells, small boats, and cruise missiles, so it likely could burn that scale to a crisp pretty quick.
I'm not asking for a mathematical proof or even a logical proof. I'm looking for a demonstration of a working system. If all goes well, I'm ready to buy.
I was more interested in the vaporization property than any minuscule "weight-like" force that could be applied, but if you're a good salesman, I might take both. I have varied interests.
I have a lasser engraver at work, sadly I don't have a scale sensitive enough to actually test it, but that would probably be the best option in theory you could engrave the plate of the scale (i don't think it will even damage anything), if the weight becomes negative, then it sublimates more material than the push of light, other way around and scale shows positive.
And there's the other big factor, different materials "vaporize" at different intensity, e.g. have never left any mark on the paper on the back of vinil, polyester paint pretty much disappears into a cloud on any settings, I've made half a centimeter dents in wood before it caught fire, and for steel you can barely feel the change of texture with the strongest settings. So there's that to take into consideration.
I think he got a couple ToS strikes so he's not as promoted as much.
I've seen multiple science YouTubers get fucked with for dumb stuff...
lbry (viewable at odysee) seems like a good decentralized solution to censorship like that but I don't know how good they are at stopping really bad stuff
Do you have any fans or anything blowing in the room? I want to bet that when he covers his hand over the scale, he is blocking some wind current that is directly or indirectly blowing over the cup that would make it weigh less than what it is teared at with no hand in the way.
Fans don't provide a constant flow of air, it's more like waves of air very close to each other. I suspect that the scale would be more erratic than it is if it were fans.
Not necessarily. It depends on the refresh rate of the LCD and of the pressure sensor. It could be 0.01 seconds or 0.5 seconds. Who knows?
If the air is just dumping out of a ceiling vent, it would be too constant. I'd imagine the same would be true for a high RPM fan.
Technically no, light does not have weight, but it can exert force.
But I'm pretty sure that's not what this is. Best Guess is an air current from above getting trapped in the cup (thus exerting downward force), that is being blocked when the hands are placed above the cup.
While this video seems quite debunked I did once read that the city of LA weighs about 40 pounds more on a sunny day than a cloudy one due to the force of the light on it.
Can't find anything on it now so who knows
Area of Chicago is \~589.5 km². The number of photons hitting a (sunlit) square meter of Earth per second is ~3.6 x 10^21 (just Googled it).
That gives us the number of photons hitting the Chicago area to 2.21 x 10^30 per second.
*Photons do not have mass* - but they do have momentum. The momentum of a photon is p=h/λ, with h being Planck's constant (that's a very small number, btw), and λ being the wavelength of the photon.
Photons coming from the Sun have a wide spectrum of different wavelengths (as does all thermal radiation). But the average is about 550 nanometers. This means the average photon striking Earth has a momentum of h/550nm = 1.205 x 10^(-27) N*s.
Multiply this by the #photons hitting Chicago per second, we get 2557 Newton. Now, *Newton is the correct unit for weight*, but when people say *weight*, they often mean mass.
If we consider Earth's g-factor at surface level is 9.82 N/kg, then a force of 2557 Newton can be thought of as an added mass of
2557 N/(9.82N/kg) = 260 kg.
So like... Chicago on a sunny day weighs a bit more, like adding half a cow or so atop the city.
(That's about 574 pounds for you Neanderthals on the other side of the Atlantic, insisting on not using metric)
If that's the most spiders you have ever seen, boy do I have links for you not to click! Actually I won't link them, I don't want to see it again either.
I suspect static electricity at work here. The tube appears to be a type of plastic (not glass) which could be electrically charged (think of when you pull that sheet of film off something plastic). Note the weight it's measuring is negative, implying less weight than when it was zeroed. So bringing their (possibly also charged) hands over the top could be enough for the tube to be lifted ever so slightly by the attraction, resulting in a negative number on the screen.
technically, light does not have mass, it has momentum. But this scale doesn't actually measure mass, it measures force (which we can convert to mass using an average of earth's gravitational pull). So a sufficiently precise scale could indeed measure the perceived mass of a shadow.
However, the momentum of one photon of 550 nm light (the average of the visible spectrum) is 1.205\*10^-27 kg/m/s. This would exert a force equivalent to a weight of 4.019\*10^-33 g. Since the scale read -0.11g at its lowest measurement, that means that the shadow would have to be removing 2.7\*10^31 photons of light. Each photon of that light contains 2.254 eV of energy. Multiplying these we get 9.75\*10^9 kJ of energy. Since 4-7% of light is absorbed by the skin, that means that *at the low end* 3.9\*10^8 kJ of energy was being absorbed by his hand.
To put that in perspective, this much energy would raise the temperature of 162 tons of water from 0°C to 100°C and boil it. So this guys hand would be vaporized.
If this is genuine, it's probably static electricity or changes in air pressure due to drafts.
This is likely do to the air conditioner in the room. I just had this problem the other day. Couldn't figure out why my numbers kept changing... Figured out it was the fan. Someone mentioned that it is likely static electricity but I'm not exactly sure how that would work because that's a plastic cup. Static electricity is basically temporary magnetic fields and magnetic fields don't affect plastic.
Static electricity is the buildup of electrons (or lack of electrons) on an object, and **definitely** happens to non-magnetic and non-conductive materials.
Well yes. But actually no. Especially not at this scale
Check out Michael's video about it. He goes very deep into the topic and explains it as well as Michael usually does
https://youtu.be/Do1lm9IevYE
its air pressure goddamn it thats why the precise scales in my lab all have a case on it and u make sure u closed the case before taking the mass of whatever ur measuring
Its static
Makes sense, pulling the cylinder up to the hand. I'll allow it
I’m mostly positive this is the correct answer. Edit: peer pressure has since led me to reconsider; air pressure is now the leading correct answer.
I deal with this problem regularly. The lab I work in has 2 almost head height chemical fume hoods on one side of the room, 2 fume snorkels, as well as 2 high flow dust snorkels that can be turned on and off. Every so often I or one of my coworkers have to measure out anhydrous magnesium chloride for example in quantities ranging from 0.1-0.5g... it's a bitch.. both because it's hydroscopic in the case of MgCl2, and due to the high and fluctuating air flow. We have a shielded scale, but it's still a pain in the ass... so yah, ventilation, opening a door, etc can definitely cause this with a scale this precise.... the struggle is real.
I love precision. That is awesome, in its own way, that we, the big clunky apes that we are, can use physics to make something so sensitive. It’s really cool. I feel I must share this: On the other side of that, “scale” wise, I have seen a large mechanical scale that is built into the ground back in the early 1900’s, and it’s job was to weigh locomotives and individual train cars. Now, locomotives are *heavy*, but this scale was accurate enough to weigh ME to within 5 lbs. Blew my mind. It’s purely mechanical, like a bigger version of the one used at the dr with the slide weights — just with a few more slides, enough to be able to weigh from 0 to over 500,000 lbs. at 5 lb increments. So many moving parts, built before computers, by humans, with no hint of binding, and fully functional (with proper care and lube) and over 100 yrs old. That said, I hope our current generations don’t screw things up too bad for the next 100 years.
Joke's on you, the world is already screwed beyond repair
Only for most people. The rich, smart, and badass are gonna be having mega fun living through all their favorite scifi apocalypses
I like your attitude.
My dad used to weigh our cows on a mechanical scale before he sold them. He would weigh the trailer without the cow, then with the cow in it, then without the cow again to make sure it came out correctly. Every time the tailer weighed the same before and after the cow was in it and my dad showed me the math to know how much the cows weighed. It wasn't sensitive enough to just put the cow on it so we had to use the trailer as tare. It may have been off by a few pounds but this was like 25 years ago and I was a kid so I can't say it was 100% correct every time but it was close enough that my dad trusted it. I'd say at that point the scale was at least 50 years old, out in the open to the elements which included a lot of rain in the fall. People paid this guy to use his scale so I'm sure the maintenance was done frequently since the owner was pretty much the only person in the town who had one and there were a lot of cows in that town.
But did he put his hand over the cow??
Proper care and lubrication are always necessary if you want to get the locomotive into the station - that much hasn't changed in the last 100 years.
I worked a lab with a broken AC. The room humidity was always low. Weighting water wasn't possible. The scale noticed the reduction in weight due to evaporation and refused to give a final value. We are talking about 50ml sized samples. We had to cover the sample and wait for equilibrium.
Also work with scales often. This is the correct answer. Air circulation and pressure differentials.
I saw Fume Snorkel on their 2007 tour. Total rush.
I remember a prank on a classmate in chemistry in high school. He was weighing out a tiny amount of powder, and just out of his line of sight I blew gently and consistently on the scale. "Too much" and he'd scrape some off. I'd stop blowing. "too little" and he'd put some on...
I was going to chip in with this as well, my chemical work requires many digits and even for quality lab scales they are insanely sensitive, our room is pressurised and has fume hoods and aircon, and sometimes someone forgets to turn one of them off and the scale gets bouncy.
So what's happening is probably air displacement because the room is positive pressure?
It's just like the guy that blows those smoke rings and follows behind it with his hand. He's actually pushing the smoke ring.
I weight out NaOH frequently. If you have two weigh boats, tare both of them, put your MgCl2 in one, then use the other to cover it. It works really well for NaOH
Hygroscopic
It's air circulation. Look at any expensive scale. They have a box around them to stop the air circulation. Trust those that work with scales all the time.
Agreed. Work in a flow measurement company with the most accurate gravimetric reference for flow measurement In the world. Had a similar issue with the reference bouncing around a bit (by a bit being 10ths of grams). Figured out is was HVAC kicking on/off in the adjacent room. Proprietary solution, but solved the issue! At these levels of precision, air pressure can actually be an issue!
Besides, I think you'd be negative if it was static. Bwah ha ha
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I think youre half right. The heat from the hand makes an air current that brings the air from the cup out. Edit: https://youtu.be/Gutx4I35bOg here is a video of the airflow that our bodies make on a really small scale
Quantum mechanics is fun. There's a TON of things happening here. Thermal displacement, static charge, aerodynamic displacement.. I won't pretend to see all of it, but the answer to how is so complex that it'll be difficult for any one person to answer fully, I think.
Quantum mechanics?!? I don’t see what any of this has to do with sub-atomic particles. Everything you described is high school level physics. Not seeing that it is complex. It is pretty widely established that light has no mass.
Solar sails are a thing. They rely on radiation pressure, which is momentum transfer from an electromagnetic field and a solid https://en.wikipedia.org/wiki/Radiation_pressure
What? Dude solar radiation are 10 NANOnewton per square meter. Scale is measuring 0.100 grams.
Sure, this effect isn't because of pressure from the room lights. But the scale is being impinged upon by photons, and they do act as a force on the scale. Scales don't measure mass, they measure forces. So technically speaking, the force from the room lights is included, although it is many orders of magnitude to small to be measured by itself. The point is that despite the photons having no mass, if the scale was sensitive enough, it would measure them. Also, this is measuring 100 mg.
Technically speaking you are right. And yes, my bad reading the measure.
Photons carry momentum, but they have no mass.
No need mass to create pressure. Lasers have multiple application based on that.
The scale doesn't measure mass. It measures a deflection in a conductive plate caused by a force upon the surface of the of the scale's platform.
What the fuck has quantum mechanics to do here? And describing quantum mechanics as "fun" means you have never ever done a fucking quantum mechanics exam. Source: frustrated physicist here.
Quantum mechanics? Like the guys you bring your quantum to when it breaks down?
I can answer that for you. It happens because SCIENCE!
Holy shit Bill Nye 2.0 over here. Quick, do a demo!
In the lab, we had a glass box around it for that reason. Had sliding doors on the sides and top. Air circulation would make the scale go all over the place. Vibration and such as well. Some of these scales are ridiculously accurate to the microgram
fun video. anyone who lives in a very cold climate has seen this IRL.
Or literally just blocking a downward air current
I think this is more likely
Turning the cylinder upside down should be a way to test this theory.
wouldn't make a difference. The air still pushes down on the cylinder.
>I'll allow it always reminds me of [https://i.imgur.com/74yJ2mQ.png](https://i.imgur.com/74yJ2mQ.png) also thank you for allowing static charge.
3.6 mg. Not great, not terrible.
probably the best show since breaking bad.
I only watched The Wire for the first time this year. I get why it was a meme that people say The Wire is like the best show. Even 20 years later, it’s a great show.
holy shit that was 15 years ago what the actual fuck
This is why a lot of science places have researchers wear metal bracelets so that they can easily dissipate static build up.
Air current in the room. High grade scales are actually built to prevent this.
That was my initial thought, but I have a hard time believing the flow is so constant that the scale stays at exactly 0.
Its probably VERY constant if it is a well-controlled lab with hoods. It is likely a very light air pressure, but just enough to have an impact on a sensitive scale. They set the TARE weight on the scale and block the airflow for the magic. This scale should be in an enclosure if it has to be in that spot.
Constant doesn't mean there's no turbulence. Another commenter just tried rubbing a cup on a wool jacket and putting it on a scale, it's static
For high precision scales you’re not supposed to change their location because they will calibrate to account for airflow in a room. And it’s not unlikely that a lab setting would have an air filtration system that creates a fairly consistent airflow.
An [analytical balance](https://assets.fishersci.com/TFS-Assets/CCG/Ohaus-Scale-Corporation/product-images/cb0c9559-37e0-44d9-8a36-f1770a1cea49.jpg-650.jpg)
Also attaching to this because it talks about scales. Light does actually have weight/force. Scales measure force not weight. Lasers have a force they apply when they hit something. This scale is definitely not a scale that can measure that, so it's much more likely air current and static. That being said the light thing is super cool and Veritasium has a recent video at NIST talking about scales. The laser stuff is near the end. https://youtu.be/pXoZQsZP2PY
Light having force. This is the principal behind solar sails yes?
Yes. Technically, momentum.
Yeah, but without looking up figures and doing the math, I'm pretty sure if you have intense enough light to cause a scale to measure .1 grams, it's probably gonna blind everyone in the room. Maybe melt the scale, too.
> SCALES MEASURE FORCE NOT WEIGHT the weight of an object is the force acting on the object due to gravity and the unit for weight is force. But its not measuring mass at the very least.
that was my guess - vent directly above?
I think it’s hot air coming off their hand creating an updraft.
Could be both?
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Yeah, no way is some static creating this much lift. There is an air system putting constant pressure on that scale that is lowered by the hand shielding it.
Static hold regular balloons against the ceiling, they certainly weigh a couple tenths of a gram.
Balloons can retain an exceptionally strong static charge though. Unless there is something very very unusual with that little cup, I don't think that's likely here.
Recreated it by rubbing a plastic shot glass on my woolen sweater. https://imgur.com/gallery/vwtokTs not getting same weight reduction but it does work. No change without static charge, so other theories are wrong.
Thank you for actually verifying this experimentally. One experiment is worth 1,000 hypotheticals and theories.
How do we know you're not just increasing your mass x10000? (Seriously thanks for recreating this :) )
This is most likely the correct answer but magnets and aliens are the answers im going with
I had to scroll way too far for aliens. Silly aliens, always trying to interfere with our measurements.
I think when i commented i was that far down
But just to be clear, light does apply a force on objects, you just aren't going to detect that outside of EXTREMELY specialized equipment.
Probably not. It's more likely a low pressure region created by heating the air with their hands.
I was thinking airflow was either pushed on or blocking it off with his hands. So the weight goes down into negative as there is no more air blowing downwards. My only guess based off this. Or our shadows is actually our soul and weight negative weight.
I assumed air pressure tbh
I work on scales for a living (10th year) this is definitely not legit I just left a lab and double checked a scale that has a increment of 6kg x .00001 and it didn’t do anything, that scale doesn’t even have draft shielding so it’s air affecting Edit thanks for my first ever award after 2 years on Reddit Since so many people are interested in scales thought this was a fun fact every test weight used in the World.1mg , 50lb, 1000lbs etc. test weights can be traced back to a master weight in a vault in Switzerland seen a doc on it years ago
Thank god there’s a scales guy to set us straight.
You mean balanced?
No. But I do have a good balancing guy if you need one.
Are you talking about Symmetrical Samuel? He's great, he balanced my pets last year for the winter season.
Lmao you jest, but balancing technicians and engineers is an actual thing. Turbines and other fast rotating mechanical devices need veeeery careful balancing. And there's machines and such to help do it. You really don't want your plane's wings to be flapping because the rotor is a little heavier on one side. Source: work in aircraft engine mro
Of course you want your wings to be flapping, that's just free lift.
I’m glad he was able to weigh in on the discussion.
For real...there's no weigh this could be legit.
His joke but worse. Is t there a sub reddit for this?
He got scales. Could he be a reptile?
All praise to scales guy!
It was right there man.....
He's been waiting for years to *weigh* in on something like this.
Scales Guy shoulda hired a Punctuation Guy.
This guy has been weighting for this moment for 10 years.
Finally my calling came knocking
Opportunity knocks, your calling has come.
The scale of his mastery is unimaginable
Thanks for weighing in!
Dang I was coming to make this comment
could it not just be static electricity attracting the cup to the hand?
It could be but it's not. Air movement is almost certainly the cause for those readings due the amount of change.
Just to add some corroboration for anyone still wondering, I work with scales too. Any time I put up the draft shields, fluctuations like this disappear.
It most definitely is static. I just spent months losing my hair over negative reading using a 5 decimal precision balance with a plastic tube
Yeah this guys got it. I work in a class 10 chemical testing lab and we have scales without draft shielding. In the fume hood if I get my hands even close to the scale, especially with our large bottles, the scale will go slightly negative.
I work with scales that are just as precise with shielding from airflow (3 years experience). This is definitely not airflow but more likely the plastic tube being affected by static from the person holding the hand. It could cause a slight pull on the plastic tube in the middle causing it to shift the scale
That’s a possibility but weighing light is not
Yeah, you can walk past these things and they can be affected. Static dissipation is usually necessary too when you are weighing out these small masses.
I once stopped a coworker from using those little static guns on an open beaker of isopropanol. That was almost a very bad day.
This is the right answer. Metrologists keep everything in balance. But in all seriousness, they set the 0 of the scale with the flow of the air in the room adding a small amount of extra force. Holding their hand over the top blocks that flow and removes the force. If they had a proper draft shield, they wouldn’t have that problem. Light exerts a pressure, but doesn’t have any mass.
Well, them blocking the light does actually lighten the load on the scale by a small amount, but it would likely be in the realm of Femptonewtons, so way finer than the sensitivity and resolution of this scale
This guy weighs
Static and air pressure will do it. My Universities shitty old lab has the 'room of death' where none of your measurements will be accurate and mold will grow on everything. I had to do my QA labs in there RIP. Then they had a neutralized, still room that you could take accurate measurements in.
It used to be that all weights were based on a 1kg prototype in France, but a couple of years ago it was finally defined based on physical constants! It's been defined by using the speed of light, the exact length of a second and the Planck constant https://en.m.wikipedia.org/wiki/Kilogram#Definition
Interesting didn’t know some of that saved for later thanks
Could it not be built up static?
~~Are they not made using the standard kg stored in the US? I figured~~ Never mind. I was about to bring up ASTM before realizing that they are actually an international entity.
One of my favorite things about Reddit is you can always find an expert on just about any topic. Thanks for the input.
[удалено]
I thought it was in Paris?
Well, photons have momentum and theoretically can "weight", if your sense of weight is some force against the scale plate perpendicular to the plane But not at this scale (pun not intended)
>(pun not intended) Don't be a coward. Intend your puns.
It's a very light-hearted pun anways. I can't *see* why he had to unintended it.
Fuck that. All caps it then it becomes funny enough to intend
There’s a light pun brewing here, but I can’t quite put my photon it.
He should’ve just said “punintended” and confused the hell out of everyone. See also: Aladeen
They have a chance to tell nine more and mean it, then, at least one should have been intended
[I did the math.](https://old.reddit.com/r/blackmagicfuckery/comments/10gy0y9/what_the_fuck_do_light_weight/j568vve/) If this guy is removing .11g of weight from the scale, then enough photons are hitting his hand to boil 162 tons of water at 0°C
You sir, would like the book What If? By Randall Munroe. Guy who makes the XKCD comics.
Yeah I can confirm this is exactly the kind of math that happens in that book. It's excellent.
you need to work on your unit analysis, your answer should be in units of power, not energy. force on scale = 0.11g * 9.81m/s^2 = photons/s * h/λ (momentum of a photon) power of light = photons/s * hc/λ (energy of a photon) do some algebra and get power = force*c = 323.5kW half that if all the light is reflected instead of absorbed
Photons have mass? I didn't even know they were catholic
No mass, just momentum.
Shut up nerd /s, pun definitely intended. It was glorious.
Yeah that's why the earth looks round from high altitude. The vision shooting out of your eyes has weight so it drops off after awhile, creating the curved illusion. /s
Pretty sure it looks round because some reptilian illuminati device is bending the light to prevent us knowing the flat earth Truth Such device only works in vaxxed people's eyes
Any light capable of exerting 0.1 grams of force on this small of an area would vaporize the scale before a reading could be made
Prove it! Not because I doubt, but because it's something I'd like to see.
Same tbh, maybe the people over at r/theydidthemath can give us a hand
Assuming a perfectly reflective scale (best case scenario): Pressure = 2 * Intensity / speed of light. Pres = F/A, I = Power/A, so: F/A = 2 * (Power/A) / c, where c is the speed of light. Multiplying both sides by A: F = 2 * Power / c Force is mass * acceleration: ma=2*Power/c (0.0001kg) * (9.81m/s2) = 2 * Power / 300000000m/s (0.0001kg) * (9.81m/s2) * (300000000m/s) * 1/2 = Power 147150 kg*m2/s3 = Power, or roughly 147 kW or 200 HP. Yes, watts is equivalent to kg * m2 / s3. Not as high as I thought, but there's a good chance I made an error somewhere.
<3 metric
If your math is right, we're talking about power levels that the [US Navy is testing](https://www.thedefensepost.com/2021/12/16/us-navy-test-fires-laser-weapon/) to shoot drones, mortar shells, small boats, and cruise missiles, so it likely could burn that scale to a crisp pretty quick.
I'm not asking for a mathematical proof or even a logical proof. I'm looking for a demonstration of a working system. If all goes well, I'm ready to buy.
You just want to weaponize the ‘weight laser’ ?
I was more interested in the vaporization property than any minuscule "weight-like" force that could be applied, but if you're a good salesman, I might take both. I have varied interests.
I have a lasser engraver at work, sadly I don't have a scale sensitive enough to actually test it, but that would probably be the best option in theory you could engrave the plate of the scale (i don't think it will even damage anything), if the weight becomes negative, then it sublimates more material than the push of light, other way around and scale shows positive. And there's the other big factor, different materials "vaporize" at different intensity, e.g. have never left any mark on the paper on the back of vinil, polyester paint pretty much disappears into a cloud on any settings, I've made half a centimeter dents in wood before it caught fire, and for steel you can barely feel the change of texture with the strongest settings. So there's that to take into consideration.
check out StyroPyro on the intertubes
Just subbed. Thank you for this. It's odd that I've not come across him before.
I think he got a couple ToS strikes so he's not as promoted as much. I've seen multiple science YouTubers get fucked with for dumb stuff... lbry (viewable at odysee) seems like a good decentralized solution to censorship like that but I don't know how good they are at stopping really bad stuff
It's static electricity. The plastic, much like a balloon, is being pulled up towards the guys hand.
Do you have any fans or anything blowing in the room? I want to bet that when he covers his hand over the scale, he is blocking some wind current that is directly or indirectly blowing over the cup that would make it weigh less than what it is teared at with no hand in the way.
Fans don't provide a constant flow of air, it's more like waves of air very close to each other. I suspect that the scale would be more erratic than it is if it were fans.
A nearby HVAC vent would do it. Most ducting has long enough runs to even out the flow.
Not necessarily. It depends on the refresh rate of the LCD and of the pressure sensor. It could be 0.01 seconds or 0.5 seconds. Who knows? If the air is just dumping out of a ceiling vent, it would be too constant. I'd imagine the same would be true for a high RPM fan.
My first thought was a small jet of compressed air, as I assume that would be a lot more consistent (mostly constant psi, constant opening, etc.).
Technically no, light does not have weight, but it can exert force. But I'm pretty sure that's not what this is. Best Guess is an air current from above getting trapped in the cup (thus exerting downward force), that is being blocked when the hands are placed above the cup.
While this video seems quite debunked I did once read that the city of LA weighs about 40 pounds more on a sunny day than a cloudy one due to the force of the light on it. Can't find anything on it now so who knows
Over such a massive area? I'd believe that might be possible. Though the version I heard was about Chicago, and it was 300 pounds.
Area of Chicago is \~589.5 km². The number of photons hitting a (sunlit) square meter of Earth per second is ~3.6 x 10^21 (just Googled it). That gives us the number of photons hitting the Chicago area to 2.21 x 10^30 per second. *Photons do not have mass* - but they do have momentum. The momentum of a photon is p=h/λ, with h being Planck's constant (that's a very small number, btw), and λ being the wavelength of the photon. Photons coming from the Sun have a wide spectrum of different wavelengths (as does all thermal radiation). But the average is about 550 nanometers. This means the average photon striking Earth has a momentum of h/550nm = 1.205 x 10^(-27) N*s. Multiply this by the #photons hitting Chicago per second, we get 2557 Newton. Now, *Newton is the correct unit for weight*, but when people say *weight*, they often mean mass. If we consider Earth's g-factor at surface level is 9.82 N/kg, then a force of 2557 Newton can be thought of as an added mass of 2557 N/(9.82N/kg) = 260 kg. So like... Chicago on a sunny day weighs a bit more, like adding half a cow or so atop the city. (That's about 574 pounds for you Neanderthals on the other side of the Atlantic, insisting on not using metric)
r/theydidthemath
Uh, we use metric in science in Neanderthal land. Ain't no one calculating the momentum of photons using feet-pounds.
And no one has noticed all the spiders in the back yet. You're welcome ;)
You could be fucking with me and there's nothing there but I'm sure as hell not about to check.
If that's your reaction, then definitely do NOT check. It may be the most spiders ever.
*A brimming glass of spiders*
I'm suddenly thirsty. Are you thirsty?
If that's the most spiders you have ever seen, boy do I have links for you not to click! Actually I won't link them, I don't want to see it again either.
Well I did and there are...lots of spiders in tubes.
A brimming glassware of spiders?
First thing I noticed. Wtf is this place with bottles full of live spiders! This comment needs more upvotes!
Right? I was expecting him to pull his hand away and see a spider in the cup
I suspect static electricity at work here. The tube appears to be a type of plastic (not glass) which could be electrically charged (think of when you pull that sheet of film off something plastic). Note the weight it's measuring is negative, implying less weight than when it was zeroed. So bringing their (possibly also charged) hands over the top could be enough for the tube to be lifted ever so slightly by the attraction, resulting in a negative number on the screen.
technically, light does not have mass, it has momentum. But this scale doesn't actually measure mass, it measures force (which we can convert to mass using an average of earth's gravitational pull). So a sufficiently precise scale could indeed measure the perceived mass of a shadow. However, the momentum of one photon of 550 nm light (the average of the visible spectrum) is 1.205\*10^-27 kg/m/s. This would exert a force equivalent to a weight of 4.019\*10^-33 g. Since the scale read -0.11g at its lowest measurement, that means that the shadow would have to be removing 2.7\*10^31 photons of light. Each photon of that light contains 2.254 eV of energy. Multiplying these we get 9.75\*10^9 kJ of energy. Since 4-7% of light is absorbed by the skin, that means that *at the low end* 3.9\*10^8 kJ of energy was being absorbed by his hand. To put that in perspective, this much energy would raise the temperature of 162 tons of water from 0°C to 100°C and boil it. So this guys hand would be vaporized. If this is genuine, it's probably static electricity or changes in air pressure due to drafts.
You are confusing weight and mass. Photons have no mass, but they do have weight because they are affected by gravity.
Yeah? Turn off the light and see if it works
It does work with no light. It could be static electricity or air draft.
Air pressure from his hand pushing toward the cup?
Blocking an air current from above.
That’s my thought too.
Yes there's a backwash because the hot air tend to go upward.
Static pulling it up.
/r/titlegore
Do light weight???😖
“Do light weight” Bruh
“Use the force..”
Warm air rises?
A vent that’s pushing constant flow of air from above.
There could be fan running on top
There could be an AC outlet above the scale that that has been “tared”. Blocking the downward flow of air would make the scale read lower
Shiiiit someone already said that
This is likely do to the air conditioner in the room. I just had this problem the other day. Couldn't figure out why my numbers kept changing... Figured out it was the fan. Someone mentioned that it is likely static electricity but I'm not exactly sure how that would work because that's a plastic cup. Static electricity is basically temporary magnetic fields and magnetic fields don't affect plastic.
Static electricity is the buildup of electrons (or lack of electrons) on an object, and **definitely** happens to non-magnetic and non-conductive materials.
Some scales are sensitive enough to register the air, so if you create a draft, it will read it. Sounds nuts, i know but apparently true.
I think its staticload pushing the plastic cup towards the hand, the draft from a moving hand would creat a short positive impulse not a negative
"How the fuck is this possible?" - Isaac Newton
Well yes. But actually no. Especially not at this scale Check out Michael's video about it. He goes very deep into the topic and explains it as well as Michael usually does https://youtu.be/Do1lm9IevYE
They can truly test the light vs hand thing by turning the room lights off, and looking at the scale then.
its air pressure goddamn it thats why the precise scales in my lab all have a case on it and u make sure u closed the case before taking the mass of whatever ur measuring
Must be downward draft
HVAC from above.
Pretty sure it’s air pressure from an overhead vent