Nicely done. i was tired of TLDR versions that basically drop a neodymium magnet inside a copper tube. At last a comprehensive explanation that even in physics lab classes at college level is sometimes overlooked. Very well done.
My dad had some small, powerful magnets, and it was fascinating dropping them down the tube of an aluminum foil roll. It was like magic how they slowly tumbled through.
Historically, a mechanical speedometer had a magnet rotating in close proximity to an aluminium disk. The ability of the disk to continuously rotate, was restricted by a spring, so as speed increased, the pointer attached to the disk would only turn as far as the tension exerted on the spring, thus indicating road speed (plus around 10% due to a legal requirement 🤣). (An early "Smiths" clockwork speedometer, worked without magnets, possibly due to patent requirements)
My lil cup bearings gummed up. Spray it with wd40 on the odd occasion i felt like digging, have a speedo for a week. My new bike? No abs, no speedo sensor... its on the engine speed, like most cars etc run off the gearbox. Means i cant change sprocket ratios :( Hate new stuff. Gimme things i can fix!
I have no idea why some German soda cans are made of steel... They are all made of aluminium in Denmark. But you're right, they are (all?) lined with a lacquer to prevent chemical reactions. Thanks for the early watch!
Since the 1935's all cans were made out of sheetsteel (iron with a bit of carbon) if I recall correctly. Mostly due production capability's. In 1965 aluminium soda cans were slowly introduced.
The last time I encountered steel soda cans was in the US Midwest in the late 1980s, a generic supermarket brand used steel cans, and seemed to transition to aluminum by the early 90s.
@@guyh3403 I assume then that the current supply comes from someone using old production equipment that hasn't broken yet. I once tried to understand which material is cheaper and why. I _think_ what i found was that raw iron starts out cheaper since it is more abundant, but aluminium is much easier to work with, so the more refinement steps there are in your production line, the cheaper it becomes to use alu over steel.
@@fabianradakovitz9064 True, but its not that much used because of weak mechanical strength. But we already have a solution for that with alu conductor steel reinforced cables.
Awesome video! Demonstrations I've never seen before. This has a real world use familiar to coin collectors. Magnetic slides made of rare earth magnets are used to test coins. A silver coin will drop slower than one made of copper or brass. It's a great and quick way to test for counterfeit silver coins.
I had forgotten that silver was more conductive than copper. Silly me. Your big magnet seems to have magnetic bald spots or lacks uniformity. All 3 samples wiggles around the middle.
I have absolutely never in teaching physics for about 15 years heard that it would be a "common misconception" that eddy currents would always cause repulsion. The idea that opposing (in Lenz's law sense) would get mixed up with physical repelling is something new to me. :S Is this a cultural, local or language thing? Has this misconception been studied in scied publications?
Back in the day we were decommissioning a 7T superconducting magnet so I took the opportunity to stick a chunk of aluminum into the bore and that was a lot of fun. Also when in service pushing the evacuated metal tube of the FT-ICR into/out-of the bore was an exercise in patience, but a free hand-held aluminum block was a more dramatically weird feeling.
The floating on water experiment might not work that well. The styrofoam usually gets "attracted" to the edge of the water by itself. I believe it's because of waters surface tension
I am here to judge RUclips's recommendations Good background music Good voice Decent visual examples Very slow video that only covers one or two simple concepts 3.5/5 Worth my time
I first realised this effect when, as a kid my Dad would let me loose on a pile of old scrap cars, and armed with screwdrivers, pliers and an adjustable spanner, I would strip out all the jewel lights, switches and gauges. I stripped out many speedometers and discovered that the cable turned a pair of magnets on an armature which were in very close proximity to an aluminium disc which had a clock-like spring attached to it and also the indicator needle. Fascinating! That was 53 years ago, now!
I anticipated the aluminum would move slower due to the higher resistance dissipating more energy as heat, but it being lighter also makes sense. edit: Now that I think of it, acceleration due to gravity isn't typically determined by weight, so I'd like to see these things fall in the presence of a magnet perpendicular to the ground.
Under idealised circumstances (steady state, which this isn't, but it's very close) the energy dissapated by inducing Eddy currents is inversely proportional to both resistivity and density. So while the aluminium has higher energy dissapation, it's not to do with it having a higher resistance, as that actually reduces the energy dissapation. In this case the braking effect is inversely proportional to the square of the density: one factor due to energy dissapation and one factor because of decreased gravity.
@@JoQeZzZ Thanks, for the explanation. I was just rewatching the video, actually looking at the calculations circa 11:00 and seeing how my expectations were completely backwards.
Always a joy to watch new stuff from you! 🥰 Do you have any plans of exploring superconductivity, or would that be too financially and safely intensive/complicated to try?
QUESTION... The last experiment, using the three samples are affected by the weight of the samples, although the copper and silver are similar in speed despite a weight difference. Could you try in a future video using the rare earth magnet on a pendulum between two blocks of silver/copper/aluminium to see the eddy current braking effect when the moving item is the same between them? The gravity effect is cancelled as the moving item is the same, but the density of the metals would be different (as well as the conductivity). GREAT VIDEO BY THE WAY!!!
Silver is the most conductive to electricity and will have stronger eddy current effects in it when exposed to a powerful magnetic field. I wish it was used in home electrical wiring but unfortunately it's not as cheap as copper. I thought silver would be the slowest to roll of the neodymium magnet, odd
@@brainiac75 that got me to thinking, those should fall slower, then I realized the upper part of the ring is a lot farther from the magnet, and so the square law is raining on the parade. And THAT got me to wondering just how much the diameter of the cylinders is affecting the test. Someone in another comment asked about racing an aluminum cylinder of the same WEIGHT as the copper one, and that's what I was thinking... the larger diameter should lower the diamagnetic repulsion farther from the magnet? But I think at that point the math is getting very ugly and a plain test would be the fastest way to get an answer. Maybe if the LENGTH of the aluminum rod was made bigger without changing the diameter? But THAT got me wondering how things compare at different places on your crazy magnet. It's strongest in the middle right? So a long cylinder may not be fairly compared to a short one?
I don't know what the deal is with Pepsi cans, but they have been using steel for 30+ years. We used to pick up cans to take to the recycler when I was a kid, and the conveyer belts at the recycling facility had strong magnets on them to attract and discard all the Pepsi cans. I think there were other brands, but everyone knew that Pepsi were no good for recycling (for aluminum prices anyway).
Excellent vid. When rolling the cylinders, did anyone notice an increase in speed through the centre of the magnet, and only a slight decrease in speed on the trailing edge. (I'm thinking this was due to increased momentum through the centre)
I remember in high school physics when the teacher had an AC coil at the base of a 1m steel rod perpendicular to the demonstration table. When he placed an aluminum ring around the steel rod it fell and rested on the top of the coil. When the power was switched on the ring rose 15-20cm off the top of the coil and danced in the alternating field. And it got quite hot.
Why should density affect the rolling speed? Both the gravitational acceleration and the rolling friction is independent of density. Could the difference be due to the surface texture?
Magnets are just fascinating... I never get tired of playing with them. I've spent countless hours trying to wrap my head around how they work. I'm convinced that whenever science can completely explain magnetism the worlds energy problems will be solved.
Every time I hear the word eddies all I can think of is this "'Eddies in the space-time continuum.' 'Ah...is he. Is he.' 'What?' 'Er, who is Eddy, then, exactly?”
There are way too many people out there, that are completely oblivious to the fact that in addition to magnetic (ferromagnetic) and non-magnetic materials, there is also the existence of diamagnetic, and paramagnetic elements & compounds. There is a whole world of exciting things to explore, more than one person can ever experience in a lifetime. There is no time to waste!!
So cool. Ive always been fascinated with magnets since i was little and they still leave me in awe. Your videos are so valuable. I love learning new things. Thanks for this and i cant wait to see more!
En ting jeg altid har tænkt på er: Hvor og hvordan i alverden opbevarer du dine store magneter? Fordi de helt store magneter må da kunne give problemer med andet elektronik eller lignende. Elsker at se dine videoer. Bliv ved med det :)
I nogle store kasser, så man ikke kan komme helt tæt på dem: ruclips.net/video/yM4Xe2c0B8M/видео.html Magnetfeltet aftager meget hurtigt med afstanden, så de er relativt harmløse på omkring halvanden meters afstand. Flere videoer på vej. Overvejer at lave en kasse med magnetisk skærmende mu-metal plader indbygget ;)
@@brainiac75 Spændende. Kunne ellers godt forstille mig at det havde været farligt hvis de ikke var pakke godt væk. Men det lyder også som en god ide med nogle kasser med magnetisk skærmning. :)
@@brainiac75 I've wondered if it's possible to build something like a Faraday cage but for magnets. I did some reading, and it does seem like you can use a metal box to "guide" the magnetic field lines, limiting how strong the magnetic fields are outside, but not to the same degree as a Faraday cage can with EM radiation. I don't have a solid grasp on the physics of it though, so I'd love to see any video you make about your experiments with storage boxes for your magnets!
You should try a ratio of the densities beginning with the inclined magnet angle for the slowest time to roll off, and multiply the ratio of one greater density to the lesser or least density and multiply that ratio of densities times the angle of the slowest time, tilt the magnet incline to that new angle and see if the densities roll off the incline in the same amount of time each.
Hm, not sure. If it was just longer to match the weight, it would likely roll at an unchanged pace. But if its diameter was larger to match the weight of the others, I think it would roll faster, because more of it would be in a weaker magnetic field farther away from the magnet. An alu soda can rolls of the magnet quite faster...
@@brainiac75 What if it was the same proportions, but larger to match the weight. Is the soda can empty? If you mentioned if the can was empty, I missed it. I am not really going anywhere with these questions, I am just curious. Eddy currents don't make sense to me, for lack of a better analogy, magical, or property biased, viscosity makes more sense to me.
1:19 German export goods, I live near the border and it is amazing how many danish people cross the border to buy alcohol, sweet and fatty stuff due to the high taxes on it in Denmark. Thanks for supporting our local economy :D
Hehe. Glad to help, but I live too far from the border to save money on it after trip costs (unless I need very large quantities) but a friend left soda steel cans after a party at my house. Very useful for science videos ;D
Aluminum, copper, and sliver not magnetic metals but still have an effect by magnetic due to eddy current effects and Lenz law. It's pretty cool that those metals are not magnetic but still have some effect by magnet. Wondering titanium and tungsten have same effect like Aluminum as those metals also not magnetic.
It's a pretty good video, but you could do another video on electromagnets, including one the scrap metal recycling industry uses to sort even lead. Covalence fields tuned to a particular frequency can attract specific metals, including gold. It's pretty nifty, mostly used in scrap yards to sort large quantities of different metals from each other. Also used when a steel mill is processing incoming metal bales to pull out the metals that can be attracted to them.
Similarly, I read before about an electromagnet called the master magnet that could attract any metal. It was simply an electromagnet with a copper disk attached to its face.
I was SO wrong about which one would be slowest. I thought copper would hold the title due to its ability to conduct electricity. Never guessed aluminium would be the winner. I also didn't know that silver was slightly more conductive than copper. Have you tried doing this with bismuth or some alloys?
I have a question, is there such as thing as an electromagnet that can be purchased anywhere on the internet that can pickup aluminum, specifically an aluminum can? I know that some garbage dumps have special eddy current separators that cost tens of thousands of dollars, but I am looking for something that is small that is battery powered, or can be powered with 120 AC, or with an AC power supply that can pickup a can. Does anything like that exist? I already found electromagnets on the internet that are cheap, and they use AC instead of DC, but I have no idea if they work on aluminum. Maybe such things are not possible to create?
You might. Say you're designing something that is inside of strong magnetic fields, or being careful that your aluminium can doesn't melt into molten aluminum when it's near an inductor
Excellent video. I haven't seen any stainless steel soda cans but now I will pay attention. I've seen another video quite some time ago where the vlogger demonstrated the diamagnetic properties of a MOUSE - a real live one.
Isn't there also a golden spot in internal resistance of the material, so aluminium is a bit worse conductor than tho other two, weighs less and that's helping it to roll slower?
Shouldn't the low density of aluminum have zero effect on its rolling time? If you drop two objects in a vacuum, they will fall at the same time regardless of their density. It's the same when rolling down a slope. The difference becomes noticeable only in the presence of air at higher speeds of movement. However, I think that in this experiment the rolling speed is so small that air resistance should not play a significant role.
How about if you move the magnets close to elements to see if when in a pushing movement what it registers on the scale and when pulling away if it registers it’s getting lighter.
Well I think, the idea is to look at the forces on the cylinders. If you use a very basic model for the friction (lets say it is equal to the normal force to the surface times some constant) we could say the the accelerating force is sin(a)m*g (a being the angle of the magnet, m the mass of the cylinder) and the force due to friction is some friction constan b times the normal force = b * (m*g*cos(a)+ c*v). c being some constant for the specific material (due to conductivity, v being the speed at which it rolls down, rememberg that the current depend on the change of magnetiv field and only occur when it rolls). Alltogether we got something like F_total= sin(a)*m*g-b*(m*g*cos(a)+c*v). Now you can see that, if you divide by the mass to get the acceleration, the "negative" acceleration from the eddie current is proportional to c/m. With smaller mass it gets larger and with bigger conductivity it gets larger. Since the factor by which the aluminum is lighter then copper and silver is bigger than the factor by which its conductivity is smaller, you see what you see. Sorry if this is not very compact :D
I love the effects of magnetic eddy currents Lol *I wonder how the electromagnetic force behaves in space, on massive scales, and really small scales?" Maybe we don't understand how massive things the scale of Galaxies behave? *I really wonder if Electromagnetism plays more of a crucial role in many different aspects of the Universe then we currently understand? Gravity, such a important aspect of nature yet seems like we don't understand "all the details about it yet" (In the form of a analogy) it really does seem like aspects of Gravity share similarities with the electromagnetic force. -Like Static charge's act upon small dust particles & allow them to acquire mass to begin gaining density. We can't have light/radiation, electricity without the electromagnetic force. The strong nuclear force seems to share similar charge behavior as well, so does chemistry. It uses +/- charges to bond compound's. I wonder if these aspects of Nature have more of a connection than we currently understand? Maybe things on different levels, strengths, size's, scales, could alter the behavior of a force we already know about. Maybe just certain things are needed, Such as temperature, density, pressure, velocity/rotation, energy/frequency/vibration, viscosity, etc. Think of how star's are created after enough mass is acquired? Radiation, light, magnetospheres, rotational velocities. They all are so crucial to Nature and all require aspects of the electromagnetic force for it to even exist.. look at a graph that shows the levels where different materials transition into different states of matter: maybe their are threshold points of (density, rotation, heat, atmospheric pressure, etc.) It's just a gut feeling I have after watching tons of science videos covering the behavior of the Universe around us. (the only way we can obtain growth and learn the things we are right about and the things need slight adjustment on? Is to be willing to allow ourselves to be open and thinking from all perspectives even on things we think we already know about.
I was thinking copper due to I have tried dropping a magnet through a waveguide of copper. But then the metals weigh is not a problem ( and I have no silver pipe for comparison ;-) )
I would like it too - but I don't have a 20x10 mm gold cylinder to compare with. I don't know if anyone makes one - at a cost I can afford ;) Thanks for the early watch!
I think it is because they are too good conductors. Aluminium's resistance is around four times lower than iron and the heat is generated in the pan by resistance to the currents ("friction" for the moving electrons). When the resistance is low in a good conductor, the heat generated is also low. Thanks for watching!
Induction cookers "shake" the pot rapidly to produce the heat. They do this by creating a constantly changing magnetic field. This can heat other metals, but is MUCH more effective with ferrous materials. (things a magnet can strongly attract) Copper and Aluminum aren't strongly attracted by a magnet. (microwave ovens have the same issue, their microwaves ONLY heat water molecules, by shaking them, and so can only heat foods with water in them, so they can't heat up an empty bowl or uncooked spaghetti for example) So to check a pot to see if it will work with induction, take a magnet with you shopping/flea-marketing, and make sure it sticks strongly to the bottom. Also, you can buy lighter pots that still work, they are made of lighter materials but they have an iron "puck" in the bottom of the pan that heats up under induction power.
I haven't got an inductive cooktop, but have always questioned why it is "stated" that aluminium will not be heated by inductance - knowing that it is influenced by changing flux ?? have you tested this ever?? (Lenz's law is generally understood as- opposing the changing flux (generally the motion of an object)- not repelling relative to the lines of flux of any absolute magnetic field..)
Nicely done. i was tired of TLDR versions that basically drop a neodymium magnet inside a copper tube.
At last a comprehensive explanation that even in physics lab classes at college level is sometimes overlooked.
Very well done.
When braniac75 is better in showing physics stuff then schools, that's when you know.
That last experiment was so awesome!
Edit: Aren't these wooden wedges the same as in the old video combining two monster magnets?
Those wedges are the one you used to combine the two monolith magnets, not the used to make the 6x4 monstrosity
My dad had some small, powerful magnets, and it was fascinating dropping them down the tube of an aluminum foil roll. It was like magic how they slowly tumbled through.
did you have to wrap a lot of layers, or is just one or two layers of foil enough?
Magnets are the closest thing we have to Magic, awesome video.
Love me a good Brainiac vid 🙂
Thanks for the early watch, Nate :D
Same here.
Historically, a mechanical speedometer had a magnet rotating in close proximity to an aluminium disk.
The ability of the disk to continuously rotate, was restricted by a spring, so as speed increased, the pointer attached to the disk would only turn as far as the tension exerted on the spring, thus indicating road speed (plus around 10% due to a legal requirement 🤣).
(An early "Smiths" clockwork speedometer, worked without magnets, possibly due to patent requirements)
And then bearings wear and magnet start to touch alu disk, needle vibrating like crazy
@@juhajuntunen7866 🤣 You don't look your age 🤣
Often, the flexible drive from the axle broke, and there was no longer any indication of speed!
@@tommiller1315 and the constant up, down, just before broke, would not of been helping
My lil cup bearings gummed up. Spray it with wd40 on the odd occasion i felt like digging, have a speedo for a week.
My new bike? No abs, no speedo sensor... its on the engine speed, like most cars etc run off the gearbox.
Means i cant change sprocket ratios :(
Hate new stuff. Gimme things i can fix!
would like to see more of these myth-busting vids!
Pure classic Brainiac magnet demos! Great stuff, thank you.
I will never get tired of magnets/magnetism. it seems like such a strange force but it effects everything differently.
RUclips shows me less and less of your videos so I make sure to binge them whenever it shows me a new one. Always fun to watch. Never change.
I had no idea there where steel soda cans. I heard some sodas can attack the aluminum more, but i thought that was solved with a liner spray.
I have no idea why some German soda cans are made of steel... They are all made of aluminium in Denmark. But you're right, they are (all?) lined with a lacquer to prevent chemical reactions. Thanks for the early watch!
Both have liner spray, but you can slightly taste steel cans from the exposed steel where you drink from. I actually like it though.
Since the 1935's all cans were made out of sheetsteel (iron with a bit of carbon) if I recall correctly.
Mostly due production capability's.
In 1965 aluminium soda cans were slowly introduced.
The last time I encountered steel soda cans was in the US Midwest in the late 1980s, a generic supermarket brand used steel cans, and seemed to transition to aluminum by the early 90s.
@@guyh3403 I assume then that the current supply comes from someone using old production equipment that hasn't broken yet.
I once tried to understand which material is cheaper and why. I _think_ what i found was that raw iron starts out cheaper since it is more abundant, but aluminium is much easier to work with, so the more refinement steps there are in your production line, the cheaper it becomes to use alu over steel.
Dang, i was just going off of conductivity and guessed silver.
I love how he changes how he pronounces aluminum every other time
I missed that.
If I'd noticed, I'd have beenistening for alumium, another name it has had.
I've never seen an iron/steel drink can before, that's pretty interesting
Conductivity per unit mass would be an interesting metric! Seems like aluminum would be near the top.
It is which is the reason its used in overhead powerlines
@@fabianradakovitz9064 True, but its not that much used because of weak mechanical strength. But we already have a solution for that with alu conductor steel reinforced cables.
Awesome video! Demonstrations I've never seen before.
This has a real world use familiar to coin collectors. Magnetic slides made of rare earth magnets are used to test coins. A silver coin will drop slower than one made of copper or brass. It's a great and quick way to test for counterfeit silver coins.
Great demonstration 👍
Glad you like it, Lexmax. And thanks for the early watch :)
I had forgotten that silver was more conductive than copper. Silly me.
Your big magnet seems to have magnetic bald spots or lacks uniformity.
All 3 samples wiggles around the middle.
I have absolutely never in teaching physics for about 15 years heard that it would be a "common misconception" that eddy currents would always cause repulsion. The idea that opposing (in Lenz's law sense) would get mixed up with physical repelling is something new to me. :S Is this a cultural, local or language thing? Has this misconception been studied in scied publications?
Back in the day we were decommissioning a 7T superconducting magnet so I took the opportunity to stick a chunk of aluminum into the bore and that was a lot of fun. Also when in service pushing the evacuated metal tube of the FT-ICR into/out-of the bore was an exercise in patience, but a free hand-held aluminum block was a more dramatically weird feeling.
The floating on water experiment might not work that well.
The styrofoam usually gets "attracted" to the edge of the water by itself. I believe it's because of waters surface tension
Would be interesting to see if lubrication changes the end results, if friction plays a role or not
Today I learned that Silver is a better conductor than Copper.
:v
Learned that thanks to the audio world.
And some think gold is the best conductor of all, but it is only a little better than aluminum... Thanks for watching!
@@brainiac75 but gold terminals won't corrode anywhere near like how copper or silver, hence gold plated terminals all over.
Physicist here. If one day I become a professor, I'll use your videos
next video idea: buy DP-75 Rottengenmeter (working or dead and make other video repairing it) and make extreme test of it
I am here to judge RUclips's recommendations
Good background music
Good voice
Decent visual examples
Very slow video that only covers one or two simple concepts
3.5/5
Worth my time
Why didn't you just say 7/10
I first realised this effect when, as a kid my Dad would let me loose on a pile of old scrap cars, and armed with screwdrivers, pliers and an adjustable spanner, I would strip out all the jewel lights, switches and gauges. I stripped out many speedometers and discovered that the cable turned a pair of magnets on an armature which were in very close proximity to an aluminium disc which had a clock-like spring attached to it and also the indicator needle. Fascinating! That was 53 years ago, now!
I'm guessing aluminum is the slowest despite being the worst conductor. Due mostly to it being significantly lighter.
I anticipated the aluminum would move slower due to the higher resistance dissipating more energy as heat, but it being lighter also makes sense.
edit: Now that I think of it, acceleration due to gravity isn't typically determined by weight, so I'd like to see these things fall in the presence of a magnet perpendicular to the ground.
Under idealised circumstances (steady state, which this isn't, but it's very close) the energy dissapated by inducing Eddy currents is inversely proportional to both resistivity and density. So while the aluminium has higher energy dissapation, it's not to do with it having a higher resistance, as that actually reduces the energy dissapation.
In this case the braking effect is inversely proportional to the square of the density: one factor due to energy dissapation and one factor because of decreased gravity.
@@JoQeZzZ Thanks, for the explanation. I was just rewatching the video, actually looking at the calculations circa 11:00 and seeing how my expectations were completely backwards.
Don't think the resistance plays a factor here
@@wesleyhayes1847 High resistance would mean weak eddy currents and thus only weak effect from the magnet.
Having higher resistance makes it worse at magnetic breaking... That's why super conductors "lock" to permanent magnets.
Always a joy to watch new stuff from you! 🥰 Do you have any plans of exploring superconductivity, or would that be too financially and safely intensive/complicated to try?
Magnets are used to sort aluminum in recycling plants. The large motorized spinning magnets fling the aluminum off the conveyor belt.
QUESTION... The last experiment, using the three samples are affected by the weight of the samples, although the copper and silver are similar in speed despite a weight difference. Could you try in a future video using the rare earth magnet on a pendulum between two blocks of silver/copper/aluminium to see the eddy current braking effect when the moving item is the same between them? The gravity effect is cancelled as the moving item is the same, but the density of the metals would be different (as well as the conductivity). GREAT VIDEO BY THE WAY!!!
Would also be good time to introduce the reason for laminated construction rather than monolithic solid blocks for some applications
Silver is the most conductive to electricity and will have stronger eddy current effects in it when exposed to a powerful magnetic field.
I wish it was used in home electrical wiring but unfortunately it's not as cheap as copper.
I thought silver would be the slowest to roll of the neodymium magnet, odd
I thought the same, but I didn't take the relative weight of the aluminum vs the silver into account.
The rings look like they came out of HDD's. I have a couple of them myself 😊
I recognized that, haha
Well spotted, they are indeed :D Thanks for the early watch.
@@brainiac75 that got me to thinking, those should fall slower, then I realized the upper part of the ring is a lot farther from the magnet, and so the square law is raining on the parade. And THAT got me to wondering just how much the diameter of the cylinders is affecting the test. Someone in another comment asked about racing an aluminum cylinder of the same WEIGHT as the copper one, and that's what I was thinking... the larger diameter should lower the diamagnetic repulsion farther from the magnet? But I think at that point the math is getting very ugly and a plain test would be the fastest way to get an answer. Maybe if the LENGTH of the aluminum rod was made bigger without changing the diameter? But THAT got me wondering how things compare at different places on your crazy magnet. It's strongest in the middle right? So a long cylinder may not be fairly compared to a short one?
0:39 ofc copper
I don't know what the deal is with Pepsi cans, but they have been using steel for 30+ years. We used to pick up cans to take to the recycler when I was a kid, and the conveyer belts at the recycling facility had strong magnets on them to attract and discard all the Pepsi cans. I think there were other brands, but everyone knew that Pepsi were no good for recycling (for aluminum prices anyway).
Excellent vid. When rolling the cylinders, did anyone notice an increase in speed through the centre of the magnet, and only a slight decrease in speed on the trailing edge. (I'm thinking this was due to increased momentum through the centre)
My thanks for keeping the monster magnet tradition alive
I remember in high school physics when the teacher had an AC coil at the base of a 1m steel rod perpendicular to the demonstration table. When he placed an aluminum ring around the steel rod it fell and rested on the top of the coil. When the power was switched on the ring rose 15-20cm off the top of the coil and danced in the alternating field. And it got quite hot.
LoL!! The flame was like, "Go on!! Leave me alone......stop it ya big bully!! ". 😂
I bet gold would roll slowly aswell?
Why should density affect the rolling speed? Both the gravitational acceleration and the rolling friction is independent of density.
Could the difference be due to the surface texture?
while coper an silver produce stronger eddy currents, they have more mass working against those currents
@@krabkit ah.. ofcourse! That was simple. Basically the moment of inertia is larger for copper and silver.
Thanks :)
Magnets are just fascinating... I never get tired of playing with them. I've spent countless hours trying to wrap my head around how they work. I'm convinced that whenever science can completely explain magnetism the worlds energy problems will be solved.
Every time I hear the word eddies all I can think of is this "'Eddies in the space-time continuum.'
'Ah...is he. Is he.'
'What?'
'Er, who is Eddy, then, exactly?”
There are way too many people out there, that are completely oblivious to the fact that in addition to magnetic (ferromagnetic) and non-magnetic materials, there is also the existence of diamagnetic, and paramagnetic elements & compounds.
There is a whole world of exciting things to explore, more than one person can ever experience in a lifetime.
There is no time to waste!!
Eddy currents and the induced magnetic field are what spin the aluminum disk in analog electric consumption meters.
So cool. Ive always been fascinated with magnets since i was little and they still leave me in awe. Your videos are so valuable. I love learning new things. Thanks for this and i cant wait to see more!
I can't imagine being bored with you around, people in my life are very uninterested in interesting things like these. 😢
En ting jeg altid har tænkt på er: Hvor og hvordan i alverden opbevarer du dine store magneter? Fordi de helt store magneter må da kunne give problemer med andet elektronik eller lignende. Elsker at se dine videoer. Bliv ved med det :)
Kan du ikke engelsk?
@@ChiseledDiamond jo hvorfor da?
I nogle store kasser, så man ikke kan komme helt tæt på dem: ruclips.net/video/yM4Xe2c0B8M/видео.html Magnetfeltet aftager meget hurtigt med afstanden, så de er relativt harmløse på omkring halvanden meters afstand. Flere videoer på vej. Overvejer at lave en kasse med magnetisk skærmende mu-metal plader indbygget ;)
@@brainiac75 Spændende. Kunne ellers godt forstille mig at det havde været farligt hvis de ikke var pakke godt væk. Men det lyder også som en god ide med nogle kasser med magnetisk skærmning. :)
@@brainiac75 I've wondered if it's possible to build something like a Faraday cage but for magnets. I did some reading, and it does seem like you can use a metal box to "guide" the magnetic field lines, limiting how strong the magnetic fields are outside, but not to the same degree as a Faraday cage can with EM radiation.
I don't have a solid grasp on the physics of it though, so I'd love to see any video you make about your experiments with storage boxes for your magnets!
I kinda wonder a bit if the part of the aluminum moving so slow is also because it lighter than the copper and silver.
I would love to see someone make an eddy current slip-n-slide
Or an elevator, as a safety mechanism.
4:24 Do you have a measureing scale to put below the magnets? Does it's weight change while slowing down the aluminium plate?
Yee a new Brainiac vid! These videos are always so well made and i always learn something new! Thanks for making these videos!
Great demonstration .. thanks for the knowledge...👍👍
You should try a ratio of the densities beginning with the inclined magnet angle for the slowest time to roll off, and multiply the ratio of one greater density to the lesser or least density and multiply that ratio of densities times the angle of the slowest time, tilt the magnet incline to that new angle and see if the densities roll off the incline in the same amount of time each.
If you took a aluminium cylinder that weight the same as the copper and silver, would it still be slower?
Hm, not sure. If it was just longer to match the weight, it would likely roll at an unchanged pace. But if its diameter was larger to match the weight of the others, I think it would roll faster, because more of it would be in a weaker magnetic field farther away from the magnet. An alu soda can rolls of the magnet quite faster...
@@brainiac75 What if it was the same proportions, but larger to match the weight. Is the soda can empty? If you mentioned if the can was empty, I missed it. I am not really going anywhere with these questions, I am just curious. Eddy currents don't make sense to me, for lack of a better analogy, magical, or property biased, viscosity makes more sense to me.
Quite impressive and, in some ways, counterintuitive.
1:19 German export goods, I live near the border and it is amazing how many danish people cross the border to buy alcohol, sweet and fatty stuff due to the high taxes on it in Denmark.
Thanks for supporting our local economy :D
Hehe. Glad to help, but I live too far from the border to save money on it after trip costs (unless I need very large quantities) but a friend left soda steel cans after a party at my house. Very useful for science videos ;D
“MAGNETS!”
-somebody on Breaking bad, I think.
Nice aspect that Aluminium was moving down slowest on the magnet. Not something that one would expect. Is this also true for an eddy current seprator?
Should try the rolling experiment in a vacuum to see the effects of Eddy currents electrically discharging atmospherically.
I needed a new Braniac video tonight, thanks!
Aluminum, copper, and sliver not magnetic metals but still have an effect by magnetic due to eddy current effects and Lenz law. It's pretty cool that those metals are not magnetic but still have some effect by magnet. Wondering titanium and tungsten have same effect like Aluminum as those metals also not magnetic.
It's a pretty good video, but you could do another video on electromagnets, including one the scrap metal recycling industry uses to sort even lead. Covalence fields tuned to a particular frequency can attract specific metals, including gold. It's pretty nifty, mostly used in scrap yards to sort large quantities of different metals from each other. Also used when a steel mill is processing incoming metal bales to pull out the metals that can be attracted to them.
Similarly, I read before about an electromagnet called the master magnet that could attract any metal. It was simply an electromagnet with a copper disk attached to its face.
Where do you even get monster magnets?🤔
i think it's linked in the video's description ;)
@@theawecat27 Idk how I did not see that, I have been a fan of Brainiac75 for a long time. Thanks For Showing Me😃
I was SO wrong about which one would be slowest. I thought copper would hold the title due to its ability to conduct electricity. Never guessed aluminium would be the winner. I also didn't know that silver was slightly more conductive than copper.
Have you tried doing this with bismuth or some alloys?
How about taking the three different metals being with porosity like swiss cheese affect the magnetic roll on the magnet Sir ???
I have a question, is there such as thing as an electromagnet that can be purchased anywhere on the internet that can pickup aluminum, specifically an aluminum can? I know that some garbage dumps have special eddy current separators that cost tens of thousands of dollars, but I am looking for something that is small that is battery powered, or can be powered with 120 AC, or with an AC power supply that can pickup a can. Does anything like that exist? I already found electromagnets on the internet that are cheap, and they use AC instead of DC, but I have no idea if they work on aluminum. Maybe such things are not possible to create?
Could there be iron impurities in the aluminium causing the attraction?
where did you get those three cylinders from? also, were any of then coated to prevent tarnishing?
Does electromagnetic induction occur when the can floats towards the stationary magnet creating almost like a feedback loop
Me: I'll never need to know any of this for real life
Also me: Fascinating.
You might. Say you're designing something that is inside of strong magnetic fields, or being careful that your aluminium can doesn't melt into molten aluminum when it's near an inductor
Excellent video. I haven't seen any stainless steel soda cans but now I will pay attention. I've seen another video quite some time ago where the vlogger demonstrated the diamagnetic properties of a MOUSE - a real live one.
Isn't there also a golden spot in internal resistance of the material, so aluminium is a bit worse conductor than tho other two, weighs less and that's helping it to roll slower?
Monster magnet were a great band but I've never heard of aluminium can!
Thanks this experiments were awesome. I guessed it wrongly - didn't account the weight difference. Again what learned.
Shouldn't the low density of aluminum have zero effect on its rolling time? If you drop two objects in a vacuum, they will fall at the same time regardless of their density. It's the same when rolling down a slope. The difference becomes noticeable only in the presence of air at higher speeds of movement. However, I think that in this experiment the rolling speed is so small that air resistance should not play a significant role.
How about if you move the magnets close to elements to see if when in a pushing movement what it registers on the scale and when pulling away if it registers it’s getting lighter.
the aluminum rings look like HDD spacers that go in-between the platters
Great video, thank you. In the last experiment, gravity was mentioned a couple of times, but how does it affect it, by means of friction?
Well I think, the idea is to look at the forces on the cylinders. If you use a very basic model for the friction (lets say it is equal to the normal force to the surface times some constant) we could say the the accelerating force is sin(a)m*g (a being the angle of the magnet, m the mass of the cylinder) and the force due to friction is some friction constan b times the normal force = b * (m*g*cos(a)+ c*v). c being some constant for the specific material (due to conductivity, v being the speed at which it rolls down, rememberg that the current depend on the change of magnetiv field and only occur when it rolls). Alltogether we got something like F_total= sin(a)*m*g-b*(m*g*cos(a)+c*v). Now you can see that, if you divide by the mass to get the acceleration, the "negative" acceleration from the eddie current is proportional to c/m. With smaller mass it gets larger and with bigger conductivity it gets larger. Since the factor by which the aluminum is lighter then copper and silver is bigger than the factor by which its conductivity is smaller, you see what you see. Sorry if this is not very compact :D
I love the effects of magnetic eddy currents Lol *I wonder how the electromagnetic force behaves in space, on massive scales, and really small scales?" Maybe we don't understand how massive things the scale of Galaxies behave?
*I really wonder if Electromagnetism plays more of a crucial role in many different aspects of the Universe then we currently understand? Gravity, such a important aspect of nature yet seems like we don't understand "all the details about it yet" (In the form of a analogy) it really does seem like aspects of Gravity share similarities with the electromagnetic force. -Like Static charge's act upon small dust particles & allow them to acquire mass to begin gaining density. We can't have light/radiation, electricity without the electromagnetic force. The strong nuclear force seems to share similar charge behavior as well, so does chemistry. It uses +/- charges to bond compound's. I wonder if these aspects of Nature have more of a connection than we currently understand? Maybe things on different levels, strengths, size's, scales, could alter the behavior of a force we already know about. Maybe just certain things are needed, Such as temperature, density, pressure, velocity/rotation, energy/frequency/vibration, viscosity, etc. Think of how star's are created after enough mass is acquired? Radiation, light, magnetospheres, rotational velocities. They all are so crucial to Nature and all require aspects of the electromagnetic force for it to even exist.. look at a graph that shows the levels where different materials transition into different states of matter: maybe their are threshold points of (density, rotation, heat, atmospheric pressure, etc.) It's just a gut feeling I have after watching tons of science videos covering the behavior of the Universe around us. (the only way we can obtain growth and learn the things we are right about and the things need slight adjustment on? Is to be willing to allow ourselves to be open and thinking from all perspectives even on things we think we already know about.
Really, reeeeaaally interesting Video! 👍😀
Was interesting to make too! Finally, I understand eddy currents 'opposing' nature :)
What does gold do?
another nice experiment that people can easily do at home is dropping a magnet through a roll of aluminium foil.
This video was strangely relaxing... 😲
I was thinking copper due to I have tried dropping a magnet through a waveguide of copper. But then the metals weigh is not a problem ( and I have no silver pipe for comparison ;-) )
Excellent video as usual. Also I
Cool but would like to see a gold cylinder react to magnets
I would like it too - but I don't have a 20x10 mm gold cylinder to compare with. I don't know if anyone makes one - at a cost I can afford ;) Thanks for the early watch!
@@brainiac75 not sure but try and ask the hacksmith
Why aluminium pans don´t work in a induction cooker ?
I think it is because they are too good conductors. Aluminium's resistance is around four times lower than iron and the heat is generated in the pan by resistance to the currents ("friction" for the moving electrons). When the resistance is low in a good conductor, the heat generated is also low. Thanks for watching!
@@brainiac75 thanks, makes sence, this was puzzling me for a long time.
Induction cookers "shake" the pot rapidly to produce the heat. They do this by creating a constantly changing magnetic field. This can heat other metals, but is MUCH more effective with ferrous materials. (things a magnet can strongly attract) Copper and Aluminum aren't strongly attracted by a magnet. (microwave ovens have the same issue, their microwaves ONLY heat water molecules, by shaking them, and so can only heat foods with water in them, so they can't heat up an empty bowl or uncooked spaghetti for example) So to check a pot to see if it will work with induction, take a magnet with you shopping/flea-marketing, and make sure it sticks strongly to the bottom. Also, you can buy lighter pots that still work, they are made of lighter materials but they have an iron "puck" in the bottom of the pan that heats up under induction power.
@@brainiac75 you might want to take a look at my reply to this question, above
would be interesting if you could make a mono pole generator since you have such huge magnets !
New video with the monster, Exciting!
Yep, they don't come that often ;) Thanks for the early watch, sulfie!
What if the pure aluminum was supercooled would it be further influenced by magnetic field
I believe silver is the most electricity conductivity so i assume it will be slowest
I haven't got an inductive cooktop, but have always questioned why it is "stated" that aluminium will not be heated by inductance - knowing that it is influenced by changing flux ?? have you tested this ever??
(Lenz's law is generally understood as- opposing the changing flux (generally the motion of an object)- not repelling relative to the lines of flux of any absolute magnetic field..)
Questions: Which one is better conductor in extreme weather as to much heat or cold?
The effects are due to trapping of the material in the magnetic field. Check superconductivity theory.
Unfortunately, superconductivity does not happen at room temperature. Wish I could invent it though ;) Thanks for the early watch!
Make the cylinders the same weight and then check the roll speeds
First I thought it was caused by the the impurities. since the alu stick is marked with 99.95&, i.e. 0.05% other metals.Does it have any effect?
The weight of the aluminum cylinder compared to the copper cylinder affects the rate of roll.
Amazing video as always