Cavendish Gravity Experiment Time Lapse Version 2
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- เผยแพร่เมื่อ 27 ก.ย. 2024
- A few years back, I posted a video of my replication of the Cavendish Experiment, which both supported the idea that all objects exert a gravitational force on all other objects and allowed for the calculation of the universal gravitational constant. Unfortunately, due to some poor planning and environmental problems, my version didn't go well. Thanks to those who pointed out some problems with the procedure ... I had no idea that that video would attract thousands of views, and numerous comments (some of which with lots of cursing!).
This version of the experiment addresses some of the issues that came up the first time around. Right now, I'd still consider this the testing phase for developing a Cavendish apparatus I'm really happy with.
In the summer of 2018, I'll be building a large-scale apparatus in my home (where I can better control environmental conditions) which should allow me to make measurements precise enough to determine the value of the gravitational constant. Be sure to subscribe and click the notifications bell so you'll receive alerts as I progress through the build and testing of the new device. See the first video in that series at • Cavendish Gravity Expe... .
81 persons didn't reproduced the experiment by themselves, yet they're still claiming it is fake... lol.
Thanks for all your effort Andrew!
If you have an iron sphere, (which by the way is denser than the supposed density of the Earth), and it is 1m in radius, and it is on top of a mountain or on a large plain (eg a desert) and suspend a needle from a thread and leave it 4mm from the sphere, on a windless day. The needle is therefore 4 thousandths of the radius of the sphere. If the sphere were planet Earth, the needle would be at a height of 4 thousandths of the Earth's radius, that is, 250th parts of the Earth's radius, that is, approximately 25km. Do you think the needle will be attracted by the force produced by the gravitational field of the sphere? If your answer is that not because the needle is being attracted by the Earth's gravity, I would tell you that you remember the branch of physics called static, suppose a zero friction surface, eg a very slippery and steely floor, if you are stopped (you are the needle now), then gravity attracts you with a force such that your acceleration is 9.8 m / s2, (your weight), but that force is canceled out by the resistance of the floor, what prevents someone from giving you a push and give you an acceleration from a vertical direction to the acceleration of gravity? Nothing because there is no friction and the weight force is canceled. Of course, your acceleration will last as long as the force of who pushed you, if it lasts about 2 seconds your final speed will be vf = acceleration per time, plus your initial speed q is zero, if it is a falling body, the time that lasts the force (weight) would be the time of fall. Returning to the example of the needle and the metal sphere, in case of not being attracted by the sphere, we could say that the force that prevents us from seeing the effect of the attraction would be the friction of the air. Well then suppose a room in the desert and where the vacuum was made, and the same needle at 2mm and a video camera with great zoom and image definition, and many frames per second, as a witness, then the needle is now at 2 thousandths parts of the radius of the metallic sphere ... That is, 1/500 of the radius of the metallic sphere. If the metallic sphere were the Earth, the needle would be at a height of 1/500 of the Earth's radius, that is, 6500km / 500. Approx 13km high. How long do you think it would take for an airplane 13 km high in free fall to fall to the ground? We can calculate it but it is not the case, intuitively we know that in much less than 1 hour. If in 1 hour the needle does not touch the metallic sphere, it would be strong evidence that the theory of universal gravitation is wrong. * The needle must be made of a non-magnetic material, and must be placed in such a way that its center of "gravity" and that of the sphere form a horizontal line to the plane. Regards!.
@@ezequielalzugaray3236 Did you finish your experiment and publish your results?
@@mrshankly213 haha no, because later, I realized that according to the theory of universal gravitation, in that iron sphere, the acceleration of gravity on its surface is millions of times less than the acceleration of gravity on Earth. Greetings from Montevideo Uruguay. Translation: google translator cortex.
@@mrshankly213 lmfao
At 6:41 the rod begins moving before you even place a bowling ball down. I think this experiment needs to take place in an environment where air currents cannot factor in.
Another factor to eliminate would be static electricity. Also, the bowling bowls are large enough to affect both ends of the beam disadvantageously - a smaller, more dense weight (say lead sphere) would surely sharpen the results.
@@1977ajax what about temps ? and why not do the experiment in a free fall environnement ?
ps : when he say's he's interraction may cause the experiment to give false result but just does not think the thing through...
@@raoulduke8110 And it's also pointless when he decides to leave the room in order to avoid disturbances but he's always there to mark down the position variations. Some people say there's no goal on doing this experiment in a vacuum chamber but there's actually a point there and still I don't know if it was already done.
I know of one torsion balance done in a chamber but it envolves magnets and it has other purposes as it's part of a bigger study and is well explained in the paper. Do you know if there is an experiment like this already?
@@curiosidadesdalife381 Yes, there is a small vacuum chamber torsion balance you can use, works well.
Agreed. The heliocentric religion dogma claims that "all mass attracts mass". If this were true, there would be billions of examples and you wouldn't need a contraption to prove it. . .
"I had no idea that that video would attract thousands of views, and numerous comments (some of which with lots of cursing!)"
Welcome to the flat earth and geocentricism debate
vertigo0331 kkkkkk
"debate"
Don't pretend your side isn't just as if not more guilty.
There is no debate.
_"F.E is all about science and visual evidence."_
LOL
Thanks for this great video -- I loved your dedication and yes, your style! Cavendish's work first fascinated me in college physics, and your work has renewed it. I also appreciate your detailed responses to comments -- like you, I didn't realize we were still debating gravity and the shape of the earth! Keep up the good work, and thanks for it -- you geek!
No one is debating gravity or the shape of the world except a few trolls who should go back to school.
2:40 one thing seems looking wrong with your experiment that the pillar on right side may effect the balance
INNOVATION & INITIATIVE Diy
The experiment detects the tiny change produced by the introduction of the test masses. Everything else has a gravitational attraction, of course, but those didn’t vary during the experiment, so didn’t produce any change in the orientation.
The pillar can't 'e'ffect anything but might affect the expt. Try to remember: affects cause effects.
I thought that straight away. It doesn't invalidate the result, but it does change where the apparatus will settle.
@@alvamiga Thats why he said a baseline before.
Every force affected it to that point. Than he made a difference (Bowlingballs) and measured the effect. Nothing wrong.
While I can see that I won't change TinyApe's mind here, he does raise a few interesting ideas that I'd like to address for anyone else who reads this. There is quite a bit to discuss, so I'll break it up in separate replies to this comment which are under the character limit for comments.
1: Air currents - as discussed in the video, there is an HVAC system feeding air to my classroom when the weather requires it. This experiment was intentionally done on a 75 degree day, at which temperature the ventilation system is shut off. There are still tiny fluctuations in the air currents associated with opening and closing doors (which I made sure did not happen), and in fact with my own motion in the room. I don't have a great idea of how to avoid small air currents associated with motion, since the experiment has to start with the bowling balls away from the balance and end with them close. Access to a large scale vacuum chamber would be ideal, but not feasible for my take on this experiment. I doubt that many would argue that a modern school with closed windows and doors and the HVAC system off is going to have more problems with air movements than a barn in 1797. Amazingly, though, our current value of G has changed very little since Cavendish’s time.
2. Wire vs. string - I agree that wire makes more sense. In the first iteration of this experiment, I used twine. I had to wait for days for the twine to stop winding and unwinding. I learned my lesson, and used plastic coated, single stranded copper wire this time. Given the amount of time this was hanging before the experiment was completed (nearly a week), and twists in the wire should have worked themselves out already. Certainly, it would be a pretty big coincidence that a pendulum with a stable equilibrium before the bowling balls in place would suddenly start unwinding a twist as soon as the bowling balls are in place.
3. Bowling ball material / electromagnetic properties - the entire pendulum setup here is made of conductive materials (iron, aluminum, and copper), and I attached the copper wire (with bare wire exposed) to a steel beam that supports it. This sytem is grounded, then, so we can expect any charge it picks up to be dissipated almost immediately. The bowling balls are made of polyurethane, which is non-conductive. While it is possible they picked up a charge at some point, I don't think this is likely. The balls are stored in an unused fume hood, all the way to one side so they contact the metallic walls. These are grounded to prevent a buildup of charge when the fan is on, which could otherwise lead to a buildup of charge on the walls, causing a spark that could ignite any flammable gasses being used or created in a chemical reaction that might be conducted in the hood. The balls are resting on cardboard platforms, which will not allow any charge on the floor to pass to the balls. The balls are made from non-ferrous material, so any magnetization the iron shells of the weights on the pendulum may have picked up will not cause forces between the pendulum and the bowling ball. Unless, of course, you suspect that I've snuck a magnet into my bowling ball to try to trick you into believing in gravity ... more on this in point 5.
4. Scientific theory - there is a common misconception in science means something that is known, but which scientists are still uncertain about. People often believe that a theory is waiting for someone to prove it so it can become scientific law. In fact, theories never become laws. Laws describe patterns in nature. In this case, the law of universal gravitation describes the pattern that all objects attract all other objects in an interaction we call gravity. The strength of this interaction is proportional to the masses of each object and the inverse of the square of the distance between them. The constant of proportionality in this relationship is G, the gravitational constant. This value has been determined experimentally since Cavendish initially performed the experiment in the late 18th century. His results lead to a value of 6.754×10−11 m3 kg−1 s−2. Since that time, other replications of the Cavendish experiment have allowed for slight corrections. More recently (within the last 10 year), atom interferometry has been used to determine the value of G as 6.67191(99)×10−11 m3 kg−1 s−2 . While there are different values measured at different times in different labs, this is to be expected given the extreme sensitivity to outside influences that a device required to measure this tiny force must have. The value for G (however it may change as we develop better ways to measure it) is, nonetheless, part of the law of universal gravitation. The fact that it's part of a law doesn't mean it's proven more than a theory, it means it's a statement of an observed pattern.
A scientific theory differs from a law, not in whether it has been "proved" or in how much evidence we have for it, but in what type of a statement is being made. Laws describe overarching patterns in nature. Theories explain why those patterns exist. A theory is a statement of the mechanism which causes observed laws (or patterns). To step away from physics, the theory of evolution does not state that populations of organisms change over time. The theory, instead, involves small changes (caused by random mutation of DNA that occur during the reproductive cycle) leading to individual organisms that have a range of different traits. Most of these differences are insubstantial, but rarely a change will cause an individual organism to either to better or worse at staying alive or reproducing than organisms without that mutation. If this organism has offspring, and its offspring inherit this different trait, we could expect them to also to do slightly better or worse at staying alive and reproducing. On a long enough time scale, we could expect that this modified trait (if favorable for survival and reproduction) will become more common in the population as a whole. On very long time scales, populations take on more of these favorable traits, while less favorable traits tend to die out. The population as a whole changes over very long periods of time as a result of random mutation of DNA and associated changes in an organisms ability to survive and mate (referred to as natural selection). The theory isn't about whether populations change or not, it's a proposal of the mechanism by which they change, and that proposal must be consistent with available evidence. To say that a statement in science is "only a theory" is to say that it is only an explanation for a well-established pattern which is supported by all available evidence. Science does not make claims of perfection, and is open to changes when new evidence requires it. If you are waiting for a theory to become a law before you take it seriously, then you misunderstand the meaning of "theory" and "law" in a science context.
5. Skeptics vs. Deniers - There is a growing trend of mistrust of science in general. While many will claim that they are simply providing skepticism to the process (which is an essential part of science), there is a line that "deniers" have crossed. In science, we are skeptical of a statement in the sense that we don't just take someone's word for it that this is the way it is. Instead, we demand the evidence they've collected to make our own analysis and reach our own conclusions. We propose and conduct different experiments to support or refute ideas. We compare ideas in one discipline to experiments in differents disciplines to check for alignment with other well-established, evidence-supported findings. When we find something that doesn't match up, we are open to changing our established understandings of the way things work. The fundamental idea in science is that a reasonable, reliable understanding of our natural world can only come from observable evidence. Scientists take a skeptical attitude throughout this process of designing experiments, collecting data, interpretting data, sharing data and interpretations, checking interpretations against existing data, designing new experiments to collect new data to check against previous interpretations, and continually refining our ideas until we find agreement between observable evidence and our own explanations of how nature works. Deniers look at that process and say, "yeah, but you didn't PROVE it."
Arguments between skeptic scientists and deniers are as unfruitful as those between scientists and faith-based thinkers. A denier argues that we shouldn't believe anything we can't prove absolutely (which is impossible). A faith-based thinker argues that evidence isn't what determines what is true and untrue, but that tradition or scripture do. A scientist argues that what is true is what is demonstrably supported by every scrap of evidence we can muster, and that if future evidence shows us what we previously believed is incorrect, then our thinking will need to be adjusted in the face of that new evidence. These arguments can't be fruitful because there is no common agreement on what constitutes a convincing argument. An argument based on all available evidence isn't good enough for a denier, and the evidence itself is meaningless to the faith-based thinker.
It is right to be skeptical in science. This means demanding supporting evidence for ideas, replicating experiments to test the evidence itself, and creating new experiments to test ideas in different ways. Being skeptical does NOT mean reading on facebook that scientists have been trying to trick us for years into thinking the Earth is round, when in fact it's flat, then refusing to accept any evidence you find because it's coming from scientists whom you now think can't be trusted.
I'm thrilled to be part of the scientific process in this medium. The idea that I can attempt to replicate parts of a well-known scientific experiment to add evidence to the overwhelming collection of evidence for the law of universal gravitation using $50 worth of materials in my high school classroom is amazing to me. While I certainly won't argue that my apparatus has the precison required to advance the current understanding or refine the current accepted value for G (6.674 08 x 10^-11 +/- 0.000 31 x 10^-11 m3 kg^-1 s^-2 from the most recent CODATA recommendations), I do think I'm able to give my students and others who find my videos chance to see this well-known, evidence-supported idea in action.
At the same time, it's extremely disheartening to be exposed to those who would make such a leap as, "your results weren't perfect and neither were some other videos I saw on TH-cam, so, therefore, Cavendish was a fraud and gravity isn't real." I simply can't fathom how any reasonable person could think along those lines.
Hi I was wondering if you knew of someone who has done this experiment successfully on a very large scale. Since gravity is supposed to increase with size, shouldn't much larger mass used to attract the torsion bar produce much more clear results? I am having a really hard time trying to find this, and was wondering if you knew off the top of your head.
Also shouldn't you be able to use something twice as massive as a bowling ball and achieve twice the results? If that is true, why didn't you use something more massive than bowling balls?
The original experiment used lead balls weighting a few hundred pounds. Washington State has an ongoing "Big G" experiment that's very successful if you're interested.
Here's where you can buy a tabletop one: www.pasco.com/prodCatalog/AP/AP-8215_gravitational-torsion-balance/
Thinks
+ Lou Jr : If there's a cute woman in the car next to my skateboard, I can definitely feel the physical attraction, in the real world! I am doing experiments and will be proposing a "hotness co-efficient" to Newton's laws in an upcoming paper.
My comment is as ludicrous as yours; the differences in masses in your example are ridiculously small in relation to the tiny force of gravity they'd have to each other. A person on skateboard's gravitational attraction to a building or car would be infinitesimal and un-measurable. Duh.
the thing is that the more you increase the size of the weights to increase attraction, the more you also increase all the frictions and constraints of the whole set up. You get more gravity, but you ruin everything because things move less freely. That's why scientists have switched to experiments using interferometry instead (lasers and stuff). It's easier to control a laser in a small vacuum than a one-ton weigh in a wind-protected and earthquake-protected tower.
Awesome ! Although you did not measure the value of G, you showed the gravitational affect on cotidian objects. Congrats and thank you very much !
Attracting girls is easier than attracting bowling balls if you were a little less nerdy.
Does the attraction of women follow the inverse-square law?
How did you ground ALL THE COMPONENTS so there is no charge?
Did you even read the five part post above?
@@57thorns Did you want to post it here so I know what you are talking about?
@@anonymousguest9290 Andrew Bennet, seems the comment is not pinned and it really needs to be.
@@57thorns And you'd like me to load and scan over 934 comments until I find it? Is that what you are proposing? Why not just copy and paste it here if you've located it?
@@anonymousguest9290 Yes, as a matter of fact I do.
Would have been nice to have moved the bowling balls to the other side of the torsion balance and got the opposite deflection angle.
It would have taken another week to make another experiment.
To do this correctly you need an isolated cabin to do the experiment in, and several days for the apparatus to get in a stable state.
Remote monitoring using cameras is of course better than moving around in the room.
Have you considered using silk thread? High strength and very twistable. You could visually see large angular displacements. There may be long term settling of the silk, but it would be a very visual and qualitative display of gravity. No lasers and fine measurements needed.
Also, find a scrap metal company and purchase a heavy hunk of metal instead of bowling balls. Or, a bunch of lead shot. ie, don't get magnetic material.
woodfirepower that does seem like it would be more effective ... the bowling balls had the virtue of being materials I already had available. I'll look around for a deal on something a little denser.
bud, make two cinder block towers and fill the cinder blocks with sand.
Bowling balls are not magnetic.
Physicist Charles Coulomb and Cavendish, 15 September 2020 - cloud.mail.ru/public/4MUd/Ao4WCYyFq
Physicist Charles Coulomb and Cavendish, 15 September 2020 - drive.google.com/file/d/1vBeRJDpISIo5eLOpJD_CliBN65DWsrpu/view?usp=sharing
I dont see how this fixes your original test. A soon as you moved out of the frame the weights started to move, even before the bowling ball was placed down.
Andrew, thank you for recording your Cavendish experiment! I particularly liked that you didn't hide how incredibly hairy the exerimental details of it are One question, and I hope it isn't too mean to ask: What gravity constant did you get from your experiment, and how does it compare with Cavendish's?
I was rewatching a marvelous video on Sixty Symbols on the Cavendish experiment (which is just fantastic BTW), and in the comments someone mentioned two videos that very easily proved the validity of the Cavendesh experiment, well the first one from Mr Lund Science actually referred to yours which was the second video in question. So I followed the rabbit hole to where it led me. I am a retired electrical engineer, but I never tire of eloquent experiments, which definitely fits well with your take on this justifiably famous experiment. Mr Lund used 25 kilogram lead brick attractor masses (possibly 26 kg masses), and just like your experimental setup, the results were just so obviously proving Scheihallion, Newton, Cavendish and most of the scientific community correct. Both of my children are in university studying two different areas of engineering. Since the experiment was such an obvious success, I have forwarded this video for them. One thing did come out of my observation of your experiment and your procedural comments in the comments section, I feel that these should be in the description section of the video, since they really did clarify some aspects of your thoughts, Cavendish's and Newton's thoughts as well. Very enjoyable, kudos to you. Cheers from Canada.
Can you do it with 4 mases? 2 of them being a lot heavier?
Those were the days! You could win a Nobel price with two bowling balls, a stick, and some wire! Nowdays you need a huge particle accelerator, or a space telescope!
Cavendish observed his resuits from outside the enclosure. Much of your persistent oscillation could be due to air disturbed by your movements, and even the convection from your warm body causing a small airflow at ground level as the warm air arises around you. Even your moving mass may be causing movement.
Not much use for calculations but a decent demonstration of the principle of the torsion balance, though.
His body is in the same place both times. Air currents would be roughly the same either time. The experiment has been repeated thousands of times in all sorts of conditions all around the world, and they all have measurable results that fit with the gravitational theory.
And ya know, the massive pillar it's right next to. And the whole building and everything in it.
@@MsHojat if they have been repeated to this standard them thousands have been mugged
Maybe fashion a cardboard enclosure for the bar, and use heavier weights like cinder blocks or exercise weights. Reverse sides of the blocks to make sure it always swings towards the blocks regardless of side.
When Everest performed the great survey of the Indian Subcontinent, the plumb bobs used to establish and maintain line annoyingly swung a bit towards the Himalayan Mountains giving a clue to calculating their mass.
So as regards "weighing the earth"... is it that you know the mass/density of the bowling balls, so you can work out the force due to that known mass... and then calculate what the earth's mass is, given that you know what force Earth's gravity exerts?
can somebody please tell me how this proves anything other than if one was to suspend an object in such a manner it will precess?
The way the object moves was influenced by the gravitacional attraction with the balls
@@marciallea-plaza4908 no - it was influenced by what you think to be gravitational attraction! Always bear in mind, nobody can PROVE the existence of gravity!
Peter & Pete they literally gave you an answer and you said “you just think that.” If not gravity, then by what process do you propose this motion is occurring? We know that gravity exists, this experiment, combined with thousands of others, verify that gravity is a very real phenomenon. en.m.wikipedia.org/wiki/Solar_eclipse_of_May_29,_1919#Observations
@@hambonesmithsonian8085 sorry, you only think that. Remember also the movement of the clear plastic tube swinging back and forth is different to the movement the uploader obtained in his previous demo where the bent rule never swung back. It's clear the uploader is fabricating his reality just like Cavendish did; people think the earth's a sipnning ball and they'll do whatever they can to find a piece of evidence to support that claim!! But the claim is clearly wrong!
@@PeterPete you’re trolling right?
THE GREEN LIGHT...IT MOVES :O
Imagine getting mad that a makeshift setup imitating an experiment that was more rigorously created to prevent outside influences isn't perfect and isn't as good as the original experiment because it wasn't as rigorously created to prevent outside influences
The flattards are just jelous that this experiment is much better set up than anything they can even dream of doing themselves, and the result is in line with the hypotheses it is based on.
In contrast to every single flattard experiment that can be trivially shown to probe either nothing, or more often the opposite of the flattard claim.
And now we can watch the flattards flood in to try do occupy our time by drowning this in comments.
I seems to me that it would be impossible to get it completely steady - air movements in the room, and even the rotation of the earth itself would be a factor.
The Earth's rotation doesn't affect this at all.
The rotation of the earth literally does not affect this
Surely the Earth's rotation must be acting as well?
Not without the rig swinging like a pendulum.
Did you take into account the Bernoulli's principle? The air between those masses also matters.
A scientist on Twitch said scientists tried to find a higher dimension with this experiment but didn't find anything spectacular. They were looking for a very weak effect & had to use more sensitive apparatus & had to take many special measures e.g. no farting
I have a question. Is there anywhere in the world a real set up experiment of Cavendish? A working one? And if not, wouldn't that be strange? Such a foundational experiment and results taken from that? Wouldn't it be of great importance for the sake of education, not to mention to proof, or test, or to take away questions and sceptisism about it?
Washington State University has the "big G" experiment. You can buy a tabletop set up to do the experiment from PASCO too. it's a pretty common college experiment.
This is an experiment that's been done and redone literally thousands of times in the last two hundred years. There are also more modern approaches such as Atom Interferometry that have been used in the last few years to calculate the value for the gravitational constant, G.
I think you are under the assumption (which I believe to be incorrect) that if there is undeniable evidence for an outcome produced by science, that people will stop denying it. I really had no idea until I posted this video and a previous version of it that there is a group of people out there who are essentially denying the existence of gravity, many of whom also believe the Earth is actually flat.
i dont deny gravity, but in my 15 years of physics carrier i actually never saw the experiment working - at least not to the degree cavendish did it , he was less then 1% off - each set up i saw was off by magnitudes :)
Most tabletop set ups are about 10% off or so. Pasco makes one that I think is within 5% accuracy. The original Cavendish one used an entire shed and as you know, the more massive the weights the better the accuracy. Washington State University's got the most elaborate ongoing experiment that I know of. Measuring G down to very close distances and so far, the inverse square law is holding up.
+Lyle Landstrom If you consider how weak the actual force appears to be, 10% for a "tabletop" measurement apparatus is pretty amazing!
A high-school kid even getting the right order of magnitude for big G, using rigorous measurement and maths is also fairly impressive.
If you put a fence of some kind around the experiment, would that make a significant difference to the effect of air currents on the pendulum? I was thinking of a kid's paddling pool, but I guess you'd need to use transparent plastic or something so that you can use your laser the same way.
He disproveed this himself. He put the setup right next to the pillar lolol. The wooden Pilar is mass also...why would it attract to the ball and not the Pilar lol
He didn't disprove himself, as pillar would exert force along radius of rotation of balls, which wouldn't do much to results.
@@tgstudio85 As it rotates weights' positions change so influence on them should be effected by the pillar due to different distances.
I like the simplicity and effectiveness of this experiment, in theory. This was a crude set up though and that kind of made it less interresting.
Hello Andrew. Awesome work, thanks for investing all the work and putting it online. I am not a flat earther, but I believe us scientists need to carefully discuss all possible sources of error, which might affect the outcome of such a sensitive experiment. In this particular setup I believe both the Bowling Balls as well as the Test Masses might have been electrostatically charged as neither the balls not the bar seem to have been very well grounded. I am sorry to say this, but by very carefully applying the correct amount of charge one would also observe an attractive force even if gravity not existed, which of course it does.
I did not look up Cavendishs original setup, but I assume by using all conductive material, clearly showing that everything is electrically well connected and also proving that by using two hollow metal balls of the same size (also being electrically well connected) do **not** create the same effect could help people to trust this experiment even more.
Oh, the laser is a really nice touch.
I think you just disproved gravity as a mass attracts mass force. Because prior to you placing the balls in the vicinity oof the hanging pole with steel weights attacched. it suddenly started twisting towards the direction where you were going to place the balls.
And then when u placed the balls it did not increase its speed any at all.
Almost as if its movement had nothing to do with the balls mass.
Even cavendish knew that his body mass would affect it according ti the theory.... this is a bad experiment until you eliminate yourself from the room
Very nice to see this experiment. However. The device started to rotate before you put the bowling balls on the floor. When i drag the youtube slider back and forward, i get the impression the device swung around the same position more or less the whole time.
Not possible at that speed
The question is whats inside that wooden thing next to the CGE experiment.
That's the frame that is holding the bar for this. It's a bit thrown together, but that was my bowling ball pendulum setup originally. I strapped a 2x10 frame with an arm to hold the top of the pendulum to a steel post in the room using tie-down straps. I also figured that some teenager was likely to try and swing the ball at the wooden frame, so I strapped a Pasco catalogue to the post to add a little dent and noise protection.
Why can't we replicate this experiment with mountain on one side?
Unless the mountain is on wheels, you can't remove the mountain for one run and restore it for the next. It's the comparison of the two runs that demonstrates the effect.
Why not use ball bearings or other pivot device? Why does torque, or how does torque play a role in gravitational forces? As in the torque from a string or wire, that would have to be overcome? So many questions.
The ideal balls for this experiment would be balls of osmium, which is beyond the budget. Tungsten balls would be the densest material that is practical to obtain, that would improve your ability to get results.
The way torque plays a role is that the wire exerts a torque that is proportional to the angle of twist, when it is displaced from its neutral position. You can measure the constant of proportionality, kappa, in tau = kappa*theta, by measuring the period of oscillation when the torsion pendulum swings without the stationary balls. You determine the moment of inertia I, from the ball and rod masses and geometry, and then use T=2*pi*sqrt(kappa/I) to solve for kappa.
Once you know the effective torsion constant of the wire, the displacement from the neutral position will tell you what torque due to gravity from the stationary balls is causing the assembly to rotate to its resting position. This will then allow you to calculate the force due to gravity between the stationary balls and the balls on the torsion rod, which is ultimately what we are interested in measuring, so we can determine the Big G. This also shows that gravity isn't only created by astronomical bodies, but also by bodies at the human scale that are practical to weigh individually, so we know both masses and the distance in F=G*M*m/r^2.
I'm five mins through. Seriously, why are you confused that by walking right past your experiment, you have unsettled it. Get the experiment shielded from outside influence...So frustrating to watch.
What if the bowling balls and also the metal bar have just the tiniest amount of electrical charge?
How much electrical charge then?
Bowling balls are made of polyester, and it can be easily discharged by touching it with metal rod.
Not unless it has some form of conductive coating, or conductive component, like graphite, within the resin. The charge is not mobile on a charged insulator, it is localised, you can change the charge at the point you touch but not universally across the surface of the object.
I'd love to set this in a huge vacuum chamber. Is there anyway one can extrapolate the results into the gravity constant number?
You'd need much, much larger balls since the friction of the string against whatever it is hanging from would be enough to mess up the experiment.
@@condorman6293 I don't think that would affect the measurement since you would calculate G by finding the torque exerted by the wire
Have you considered the gravitational effect of the pillar (with the large board attached to it)? It's quite close.
The pillar is a constant in both set-ups (i.e. without the bowling balls, and with).
As said above.
True, but the pillar doesn't move, so its presence wouldn't cause a change in the equilibrium position. The bigger issue here is the lack of shielding against electromagnetic forces.
How did you discount other variables that could have affected your results like temperature? It's more than possible temperature differentials between the objects could have caused a pressure differential field to exist between the objects thus causing them to move. Air flows within the room too! For greater conclusivity you need to do this demo in a vacuum where even temperature can be consistent throughout all objects. It is literally insane to use Cavendish's experiment to support the idea of gravity!
Nope. He used this experiment in the 1800s, found out the gravitational constant wich has proven to correct time and time again.
@@txm100 tks for replying but you're only supporting an IDEA that's been put forward as fact. I'm sorry to burst your dreams! If you actually carried out this demo with an UNBIASED MIND you'd have to ask yourself whether variables other than the idea of a gravitational constant could affect the results!
So what other plausible explanations could account for any attraction, if any observed? Perhaps trace amounts of iron within the lead balls? Perhaps temperature differentials between the objects? Perhaps movement in the apparatus also?
You're living in a dream world if you think cavendish proved a gravitational constant over 100yrs ago
fascinating, thanks for taking the time
Could you please provide us with a list of the specific materials you used in this project? Thank you.
Two 4 big heavy hunks of material(better not be magnetic), bar, a steel wire, a laser and a mirror.
The idea that if one shoots a cannonball straight up in the air at the earth’s equator (which has a rotational velocity of about 1000 miles/hr) that it would fall behind or forward by a certain distance is false. Go on a jet plane (traveling at a constant velocity at about 500 miles/hr) and throw a ball straight up in the air. Or stand in the isle and drop a ball from a high height. I will put money down there will be NO deflection of the ball whatsoever. Now do the same with the plane at a complete stop. I’m sure the same thing will happen; the ball will fall straight down. But note that the entire earth with everything on it is spinning at a constant velocity (at the equator at 1000 miles/hr). Only if the inertial frame (the jet plane in this case) is changing its velocity or direction will one see the ball veer from dropping straight down. Since the earth and everything on it is spinning at a constant velocity, one will see NO deflection.
The point about using a cannon on the equator is that the cannon will shoot its shell far enough into the air to show an effect. Dropping a ball a mere metre or two from your hand will not show a measurable effect. The minor muscle tremors from your hand holding still is enough to swamp out any effect you might be able to measure.
There would be a tiny tiny deflection if one dropped the ball on earth’s surface as there is a very slight difference in the rotational velocity of the ball held at about 5 ft high and at the surface of the earth. If one precisely dropped the ball on the jet I’m thinking that there would be a similar tiny deflection all things being the same with the jet moving at a uniform velocity and direction. Someone calculated the deflection of a hypothetical tower of 5,000 ft from NYC and it was about .5 inch. So using this result for 5 ft, the deflection would be 0.0001 inch. So to correct my statement, there is a deflection but it’s a very small amount.
MUH DENSITY
M-MUH WEIGHT
MUH AETHER MAGNETIC FORCES
Could you please explain how to measure a theory?
en.wikipedia.org/wiki/Gravity#Newton's_theory_of_gravitation
@@camper089 this guy literally just created a video that you're commenting on that did that...
@@camper089 1. Scientific theory!= theory. A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment. Such fact-supported theories are not "guesses" but reliable accounts of the real world.
2. Newton published Law of Gravitation, not Theory of Gravity.
How do you know it's not from the moon? was the position of the moon the same in both experiments?
Lmao what?
One ball is next to a metal I beam!!! Would that intervfere with teh experiment? Even breathing woudl affect it. Utter bullshit.
Yes, absolute utter bullshite!! 👍
Would you mind testing that to verify?
Now try something else, having a bowling ball suspended in the air and putting a small weight on a balance, like a scale, s few inches below the ball, with the other side of the balance farther away from the ball. Then we'll see if the ball is really exerting gravitational force or not. The horizontal rotation of the Cavendish experiment could be caused by something other than gravity, for all anyone knows. Pulling something upward, against earth's gravity, would be more convincing.
Get the coriolis force into account as a Focault pendulum would show.
Way to go showing you don’t understand a Foucault pendulum.
Even before he put down the second ball the laser was already outside of the oscillation range. Gravity is real, people.
Ok. I don't really understand why it's oscillating. Can someone please explain this to me?
Essentially, the bar is a horizontal pendulum. There's nothing to prevent the bar swinging once something sets it in motion, except for the friction in the wire resisting its twisting. But that's too small compared to the motion induced by Andrew walking around the apparatus. If this was a proper experiment instead of a demonstration, he'd do what Cavendish did and set it up in an enclosed area, then let it settle for a time before observing it.
I would've liked to see removal of the bowling balls and it's return to the original angle. Very interesting experiment though.
Someone explain this. Physicist Gates found self correcting code, Adikras, in string theory last year, this year Musk says he's 100% sure we live in a simulation. My question. Are simulations created or can code evolve from nothing.
Mike Franco I think you’re taking the argument a little too literally. I’d suggest checking out solipsism. Even if this was a simulation, it would be very difficult to prove one way or another, we probably could never even test it. So why worry about the tiny details if we can’t tell the difference?
It looks like that suspension wire is creeping. It should be quartz - or at least a glass thread. And a very light gauge copper wire to ground the bar. And I'm pretty sure those bowling balls are insulating enough to carry some residual electrostatic charge. Lead or brass weights would be ideal - grounded of course.
So if you had paid attention you would know the wire WAS COPPER AND GROUNDED.... and how did you notice the alleged creep? Just saying.
@@jimmiller5891 Copper creeps under tension. Sorry, but that is just a fact. That's why suspensions for these kinds of system are drawn quartz glass. Even these will need a few days to stabilise. The ground should be made with a very fine copper wire draped loosely along the quartz fibre. But the big grounding issue you have is the bowling balls themselves. They will inevitably carry a static charge on their non-conducting surface. They should be something like brass so the electric charge can be grounded. Also obviously non-magnetic. Bear in mind that the electrostatic force is about 10^37 times as great as the gravitational force. That makes the likelihood that you observed any gravitational effect at all here close to zero.
@@jimmiller5891 Just to add. A back-of-an-envelope calculation gives an estimate of less than a microgram of actual gravitational force present in your experiment. Are you seriously trying to fool yourself into thinking that you saw that? If you didn't do the sum first, shame on you. If you did, and still presented this as if it were real, even more shame on you.
Even the slightest fart would interfere.
this was really helpful! thank u for posting
Must be real he's wearing a tie
What the use of tiptoeing when there's an office party upstairs, where the cable is attached. Not to mention the 2 tonnes concrete column right next to one these masses !
Yeah but those columns did move during the experiment did they?
@@psychalogy I thought we were measuring gravity? The pillars don't count?
@@Volleyball_Chess_and_Geoguessr Not unless they move they don't. As long as they are stationary with respect to the experiment their influence on it will be a constant.
You also should remember that this follows the inverse square law, so as long as the two test masses are very close together and are a good distance from any other mass in the horizontal direction, it shouldn’t effect the experiment too much.
the thing with the cavendish expariment is theres always so many factors involved with the cause of the movement of the weights thats its near impossible to pindown "Mass" being the cause of attraction between two object.....
earthbe c. if you investigate the original experiments he didn't just knock this up in a few days and take a couple of readings. It was carried out over a year and many many measurements were taken under rather robust conditions. All of which would were peer reviewed at the time.
The swinging interval the reflected laser makes is the noise. Your signal ought to be 10x larger than that to be able to make conclusions. Also, after detecting a reading with the balls you need to remove them to verify that the system returns to the same initial spot (state). Finally, you will need to calculate the actual force, if any, because the scientific method calls for the match between a theory and the experiment. You didn't do that. The tortion string is a good idea. However, your movement around the room upsets the equilibrium (just as you suspected) and I would go as far as to say that the air conditioning openings can/does affect the equilibrium just the same. You may think about replacing balls with containers you can fill remotely with water, say. If anything, your vid is a good example of not following the scientific method.
Awesome video!
shouldn´t a force apply always? sometimes yes, sometimes not , sometimes more, and sometimes less.. isn´t that called chance? hmmm.....
why oscillate?
Jagad Hariseno its analogous to pulling on a spring, after you let go, the spring will bounce around right?
You proved gravity! All the other stuff in the room including you are impacting your experiment...
I was just wondering why you didn't put this in an enclosure or maybe a heavy enclosure to eliminate the impact of other G forces?
Were you concerned that bouncing the laser on the apparatus would provide some kind of thrust?
I'm not sure you understand how gravity works if you think that a heavy enclosure will eliminate it...
everybody’s talking about flat earth ears so much all the f,at earth comments are gone lmao
Run it again twice with your masses on both sides (right-handed and left-handed) and show the math to calculate G.
Cavendish build 👍 blue marble science guy TH-cam channel.
Next time loose your tie before doing anything.
I cannot read all comments, so this may be a repeat observance?
As this experiment is so sensitive to airflow, the Bowling balls could act as a shelter or attraction or at least divert the flow of air?
The original Cavendish was encased for this very reason!
kudos mate for trying this experiment to defend the heliocentric model.i am at this moment a flat earther because of all of the other experiments i have seen by noted physicists of their day I:E lack of curvature,having two opposing pressure systems without a solid barrier between them.the lack of the earths rotation and the presence of aether.that being said i still have problems with the heliocentric model and questions,the reasons for appluading you are that this is the only way we will decide the issue practical experiments and not theorys written on a blackboard so thank you but it will take a lot more convincing for me:)
Wouldn't that big ass pillar effect this as well?
The pillar is a constant in both set-ups (i.e. without the bowling balls, and with).
why was this done next to a huge column which would exert its own pull on the masses?
When I was watching this, I was constantly wondering why isn't that scale tilting all the way to the bowling ball on the right (like shouldn't its pull also add up and twist the weights even further), and your comment basically answered that question for me.
If there is a gravitational pull at ALL you would see one side glued to the earth, or the other, since the EARTH is the largest mass involved in this EXPERIMENT! (Sorry excuse for one, if u ask me, but....)
And, of course that 1.5° angle shift was twice actual shift, since the reflected beam is deflected through twice the angle that the mirror rotates.
where was the control experiment this is very average science b+ for effort c- for convincing data
Switching off gravity is problematic.
The coriolis effect,humidity, air movements,temperature, vibrations,the material of the various components,
(for example the thread) of this structure, makes measuring inaccurate...even wrong.
But for those who do not believe in gravity, I propose to jump out of a flying plane without a parachute.
It can be enlightening for a short time.
( Please, don´t do it...) :-)
It would be really cool if you redo the experiment using non-metalic objects, that are hard to get electrostatic energy in them, in the system, also changing left and right side of the mass body. Just so it will be absolutely clear for even the blind and the debate can finaly be put to rest. ( There are such versions, even with video, but either non-english or poor quality )
How does this prove gravity
All they can do is show you the experimental proofs, they can't make you understand them. That's on you and your IQ, or lack thereof.
psychalogy that’s a sad way to look at things, IQ simply determines how quickly one person can comprehend information. You should do your best to explain to others who are legitimately curious. You and your condescending toxicity are the reason flat earthers are so prevalent.
Basically, the force experienced by the two balls correspond to the twist of the spring that’s holding up the whole ensemble. Since the guy in the video knows the masses of the bowling balls, the angle of deflection, the spring constant of the spring, and the distance between the bowling balls he can do some algebra to calculate the value of what’s known as the gravitational constant.
Вы снова коснулись дороги. Я псих.
Even replicated the office air coming on to move the device... 😂 😂 😂
That wasn't office air.
The Cavendish experiments have been conducted multiple times.
It was proven in all cases
Why would it swing AWAY from the bowling balls?
The torque of the wire
@@rinse-esnir4010 Torque Smork. I twould eventually settle down. How did the moon form by rocks sticking to each other like magnets if they were torquing away from each other? Why when we jump do we not torque away from earth as we see the balls doing here?
@@Volleyball_Chess_and_Geoguessr It won't settle down, because when the wire is unravelled, the gravity pulls the balls towards eachother, creating torque, which eventually overcomes the gravity pull and makes the balls swinging back. And so on, and so on. When setup correctly, the gravity pull and torque are in balance, keeping the balls swinging back and forth.
We don't know how the moon was formed, most likely it was created after the earth was hit by another celestial body.
@@Volleyball_Chess_and_Geoguessr You don't seem to understand torque. If you twist a wire, you create a torque. When you release the wire, it unravels, releasing the torque.
You don't create a similar torque when jumping up: you just apply a counter force with your legs, and when that force stops, you fall back to the earth.
@@Volleyball_Chess_and_Geoguessr No, it won't settle down, because as soon as the string is at rest, gravity pulls the balls towards eachother.
I will make you 1 k subs today
just you moving about the room is causing the movement. you can't do this experiment in these conditions.
He did and he got results.
The gravitation model does not work. You are misunderstanding the "reality". Forces coms from outside... As the middling of air and water.
The gravitational model works well enough to keep buildings and bridges up, aircraft flying, boats floating and spaceprobes flying, not to mention predicting the motions of heavenly bodies. Flat Earth predicts nothing.
So...you're telling me that two bowling balls curved the fabric of spacetime enough to see a change over 2 degrees? Shine a laser past one then. If the light bends, I'll believe you. So far, whatever this phenomenon is, it doesn't look like gravity. Wouldn't we expect the instrument to - over time - reduce it's field of swing dramatically and rest next to the bowling balls eventually without moving?
The gravitational field needed to detect such a bend in a laser would need a much higher mass, like the scale of a planet or a star. You might be able to detect a curve in that beams path? But it would require ridiculously sensitive equipment. Here’s an experiment that occurred over a century ago that would meet your specifications en.m.wikipedia.org/wiki/Solar_eclipse_of_May_29,_1919#Observations
@@hambonesmithsonian8085 yeh, I know about general relativity, I'm saying though, is a bowling ball _actually_ curving the fabric of spacetime enough to influence other objects? Or is this something else... If this _was_ the case, wouldn't astronauts just be constantly being hit by floating objects in the ISS, drawing objects like pens into orbit around themselves? Dude, I want to understand gravity. I really do. But so far, no one understands it. Einstein had an idea, but, it's not finished, so physicists all over the world are working with it because there is so little creativity to generate any new ideas. Maybe one day... until then, so much doesn't fit together.
Ben Simpson it’s most definitely gravity, what you have to remember is that gravity is an extremely weak force. Which is why this experiment takes as long as it does. Do you have a discord? I could explain better on there. I don’t want to pollute the comment section.
@@hambonesmithsonian8085 riiiight. But gravity isn't a force, it's an illusion given from spacetime curvature due to mass-energy (or so it is currently believed). Also, it's hardly weak. Earth is 150M km from the Sun and yet we've been orbiting it for billions of years. So...I don't know how you could say it's weak. Try to use your magnet from where you are, and I'll hold out this piece of metal... I'll wait.
Ben Simpson gravity is extremely weak compared to other forces. Notice how you can use a tiny magnet to pick up a paper clip right? How else could a magnet overcome the gravitational pull of the entire planet?
A scientist should avoid using superstitious expressions such as "cross your fingers" implying that success is based on luck.
Patrick Coston A scientist is just an educated person. Figures of speech are what persons use. Your comment is silly.
G constant does not exist. Why does that giant steel girder not have its own "gravity?"
Hey salzmann
Next day: pretty stable. Air current. Right. Is this the exact test Cavendish did? No? Then it’s null.
No one else hear the static?
this is obviously not a valid result )
you know that in the experiment the cavendish used balls weighing 150kg, and you have balls of 7kg. and at the same time you measured the shift of equilibrium comparable with the cavendish? :)
firstly, it would be nice to describe the installation parameters, the mass of loads and balls, the length of the bar and cable.
if i suppose that sphere is about 10kg and one weight on the bar is 2kg and distance is 30cm, than the force will be f = g * 10 * 2 / (0.3**2) = 1.46e-8, multiplying by 1e5 will give us equivalent weight: 0.0015 mg, multiplying by two finally we have 0.003 mg. you just can not imagine how small is this force to shift your equilibrium at some noticeable angle )
btw, force in cavendish experiment was something about 0.015 mg. and he measured the shift of equilibrium about 2.3 degrees )
and, of course, after such an arrangement of the balls, one would have to try to put them on the other side of the crossbar in order to get the balance shifted to the other side.
and conduct a series of ten experiments with the fixation of such shifts in different directions.
Good sir, most bowling balls are only 16 lbs to 8 lbs. Average male weight is 150 lbs. According to your description of gravity. Should you not remove the large 150 lb weight from the room to control for outside forces? Or is your weight automatically ignored by the setup?
I don't want to crunch the numbers on exactly how far away your mass needs to be to control for it. I'm too lazy for that. But you are too lazy to control your experiment properly so who is the real idiot?
The experimenter is much further away from the pendulum than the bowling balls. On the order of ten times further away, which by inverse-square law means that the effect is attenuated by one hundred times. He also has the same effect on both weights in the pendulum which shouldn't affect the oscillation at all. He's also in the same position in both set-ups, i.e. with the bowling balls and without, by the graph paper, so his mass is a constant.
At least you were aware of distance. Distance is a huge factor; it weakens gravitational force by the _squared_ amount rather than mass which is linear. That said, what you didn't consider is all the other heavy masses in the picture, and how they were constant. The man in the room is just another constant just like everything else. As long as he stays in one spot, and in the same spot during the two measurements it's not a problem.
That said, to do some simple rough math, I'd say the balls re about 6 in from the test masses, there's two of them, and the tester looks to be at least 4 feet away. Some basic math 2*(4/.5)^2 means he'd have to weigh 128 times more than a bowling ball to have the same impact as the bowling balls have. Not only that, but like I said even if he was a significant force, it wouldn't matter as long as he stayed in the same spot for both tests. The test involves comparing with and without the masses. If a consistent difference can be measured between those two conditions, the experiment is very likely to not be any sort of fluke from interference when multiple averages are taken like he did. It then becomes virtually impossible to not be totally accurate and as good as fact when thousands of people all over the world repeat the same test with the same sort of results. It's not a coincidence. It doesn't need to be precise perfect. It needs to have noticeable difference.
This is a joke of course the balls move, they have been magnetized.
AIr pressure, movement within the room. He needs to be out of the room all together. movement doesn't means its because of gravity. Magnetism, static electricity, lights in the room...micro air movment....this experiment is not science.
he didn't observe anything but a random swinging bar
Wilson Garcia I’m almost in shock. This is the definition of pseudoscience. Yet, Cavendish crested big G with this?
Chris Berry
our constant for gravity(6.67408 × 10-11 m3 kg-1 s-2) may not be exactly precise. but its precise enough to launch satelites and map trajectories for space crafts. how we measure time is also imperfect and due to time dilation on satellites it requires constant adjustment and calculation, based on gravitational and movement differences, from places on earth. *but wilson is right i think we witnessed a swinging bar and not much more. poorly conducted and measured experiment*
I think you got it exactly right. The bar was rotating. Here is the good part: rotating due at least in part to a concept we call gravity.
It is called simple harmonic motion - which is precisely what we epexct to see.
Wilson Garcia
So would you care to explain why you skipped that part of the video that shows the shift in the centre of oscillation ?