Knows his stuff, Learns from his mistakes and shows all the details, great channel.

FUN FACT: Did you know that they use this process for the brakes on drop tower rides. Like Drop Line at DollyWood and Panic Plunge at SilverWood theme parks. There's a couple of reasons for using this magnetic system as appose to using friction brakes. 1). It will never wear out, which means it will work with 100% reliability, Something that you want when you're dropping a ride vehicle from 200 feet in the air. 2). It only activates when the ride vehicle is moving faster then the configured speed. This is important so it doesn't put a load on the ride vehicle while it's being hoisted to the top of the tower. This process is 100% passive.

Something you could have done/ could do in the next installment would be to place the tube on a scale, showing its weight. As the magnet enters and flows down the tube, it should show an increased weight, and will show a further increase when the magnet touches down to the surface of the scale. The ratio of the difference between the falling weight and the Landes weight is the percentage of the acceleration due to gravity that is resisted by the eddy currents produced by the moving magnetic feild.

This is actually a very known phenomenon, metal impurities affect the conductivity of those metals very negatively. A copper silver alloy has worse conductivity than both those metals in their pure form. And even small impurities already show a negative effect, just 0.1% copper is needed to make the alloy a worse conductor than both. Thats why for electric installations of all kind you want 99.99% pure copper.

Thank you for your incredible support this year! I'm looking forward to working on a bunch of exciting new projects in 2024. Wishing you all a fantastic Christmas! 🎄🍻

I have been fascinated by magnets my whole life, and I am 62 now and still in wonder 😅 They one of nature's true miracles.

When a small neodymium magnet ball descends through a copper tube under the influence of gravity, it induces an electric current due to the change in magnetic flux within the tube. This phenomenon is called electromagnetic induction. According to Faraday's law, electromagnetic induction creates a current directed to produce a magnetic field opposing the change in the source of that current. The formula for Faraday's law is: ε = -N * (dΦ/dt) where: ε - induced electromotive force (emf), N - number of turns (in the case of the tube, it could be replaced with other parameters related to the tube's geometry), (dΦ/dt) - rate of change of magnetic flux.

If conductivity is the driving factor in this interaction, try melting copper wire as the source for your metal. The copper used in water pipes is allowed a much looser tolerance for impurities, and only a percent or two can make a noticeable difference in resistance. I'd be curious to see if pure silver works better for similar reasons.

It would have been interesting to hook a VOM up to either end of the metal tubes and see if measurable voltage and current are being induced.

I was waiting for you to demonstrate copper over silver in the end-to-end demo so we could really get a feel for the speed difference. Maybe try that with the twenty pounders? Super cool video. Thanks for sharing!

So glad I found this channel again! I used to have all your bronze casting videos bookmarked.

Beautiful the way you handle those materials (casting).

I was surprised you didn't stack the tubes alternately, Cu, Ag, Cu, Ag, and see the drop speed transition between the segments. Seemed like a lot of work, but nice demo!

Hey Mr Robinson! I see that cracking is an all too common issue with the suspend a slurry molds and I have a suggestion.. usually any cracking is a result of thermal expansion where excess moisture is present in the mold, and what I would suggest to avoid this in the future is to go ahead and put your mold inside of a filament dryer or dehydrator for 24-48 hours at 50 degrees C, this will help to remove any excess moisture in your mold before burnout and you should avoid the cracking issue. Of course there are other reasons why a mold might crack for example in parts of the mold that were not evenly coated with a thick enough layer but assuming that’s not the case, I think dehydrating is a prudent step to take for preventing moisture related cracks

Great experiment illustrates the idea of damping due to electrical current generated from a moving magnet .

thanks for running this with great camera angles it answered a question I had after seeing the opening scene .

Another great video. For someone who is very new to casting videos, the background of your shop looks very interesting. I checked most of your old videos, and did not find anything about a shop tour. I know I would be very interested in seeing a video tour of your shop and some comment on all the tools you use. I hope others might feel the same. Regards.

Man, I wish I had you as a physics teacher back in high school. This experiment looks just awesome

1st timer watching. I like watching the construction process. Instead of searching for copper or silver thick tubing out in the Aether-net someplace, and you could just buy it💸. You made the whole project from raw materials?!. Fantastic! Also shows the pitfalls that can happen with different alloys. Good comments from one of your commenters about the small percentage of impurities. Just show how much room for more novel inventions to be made. Thanks.

Nice workshop there. Kiln furnace, sand blaster etc. quite nice.

Could be intresting to have one long tube with a slit cut out along the side so you can watch the ball drop, and have the tube have sections of different metals so you can see the speed changes

Love your videos! This was super cool to see in action. A neat thing to try would be to put the tube on a weigh scale and see the weight increase when you drop the magnet through, even though it's not touching the tube.

The way you knock the molds to the side before closing the lid gives me chills 🥶

This is wild! Thanks! Molten silver sure is pretty! I love the high-speed sound effects!

Dude, you have a cool workshop and great tools!

The reduced speed of the magnet is almost peaceful and tranquil. I'm a lover of puzzles too, I'm wondering if it would be possible if the integration of the reduced speed could be incorporated into a puzzle somehow. Cool video.

You investigated something different with this classical experiment. That was innovative, informative and interesting. Thanks for doing this and sharing your results.

Do you guys know how much of all the world's discoveries and technology have occurred due to garage investigators like this? We really owe them.

This is an interesting and worthwhile experiment. I see this being used for large scale elevators. You could use a silver section for the initial slowing of an elevator because it's not as strong or abrupt, then use the copper part to slow it down further, before using an electro magnet to bring the elevator to a complete stop. You'll have a nice and smooth slowing and stop. Well done fella, and I absolutely love magnets and their potential 😊

Always appreciate the videos. I hope to get my own foundry setup and it is useful to see the challenges.

Beautiful, masterful, scientific artwork!

A beautiful presentation thank you for sharing with all the Utube community loved it 👍🌟

I think you should try cooling the magnet or the tubes and see if it changes anything. I mean really Cold. It will be fun to see if it will act like a super conductor does when placed over something like liquid nitrogen. It hovers above the cold object.

I have an experiment for you. Take a shot at weighing the combo while the ball is falling through the tubes. But first, try to calculate the forces and determine the weight that you expected.

I can see this guy is pretty serious about his work/hobby, he must have a fortune invested in his equipment. Interesting show.

That was both incredible and educational!

wow that is so cool ! ! ! can't wait to see your "Big Copper Tube" ! ! . . . so . . . if you had drilled a hole and installed a rod in the side of the tube and put a little motor on to rotate it - the magnet ball could levitate inside as long as the motor rotates the tube like you were ! ! COOLNESS and AWESOMENESS at the same time ! 😀🌏

I'm curious what mulitple copper rings sandwiched between plastic washers would do. Might allow the magnetic field to switch faster

My son and I really enjoyed this video. It was fun to explain to him how this works 😊

see now the memory IS returning, this is positive so... with this video i can say that its a step closer to your once valued anti gravinty remember that you already had your high tech era. keep up the good work.🎉❤

This works the other way around as well. If you drop the metal through a strong magnetic field it will result in the same effect. I used a magnet from a hard disk drive, which has a gap that a coin can pass through, and a very strong field that allows for very precise positioning of the read/write heads. Interestingly a US Nickel falls freely through the field even though it is 75% copper and 25% nickel. A silver bullion coin (99.9% silver) slows way down. A US Quarter Dollar (8.33% nickel & 91.67% copper) does slow through the magnet but not as much as pure silver. Interestingly, the nickel is an alloy, (as is the Sterling silver) whereas the quarter is a clad structure, with a copper/nickel alloy around a pure copper center.

It seems to me that with a lathe, you could use a boring bar and machine the inside of the "pipe" to make tighter tolerances. With the demonstration of the ball stopping when the two copper "pipes" were sitting on the table, I'm thinking that the gap space between the magnet and the inside diameter plays a significant role. By boring the inside of the pipe to slightly different diameters, compared to the magnet's outside diameter, you can get different results.

How nice to see the Muggles catching up with very old science. Maxwell used the same principle to explain magnetic levitation over 170 years ago. So much for 'science education'.

Did you try stacking the copper and silver alternating on top of each other? Curious what that would do?

For thick cast silver tubing you can buy jewelers wax tubes and casting investment then do a similar kiln burnout for a much faster and more cleaner and consistent casting. The whole process takes much less time (12 hours) and the end product will be much cleaner. Or, you can just order extruded silver tubing. It’s not that expensive. Most jewelry supply houses can order any tube diameter you need. Just my .02 from a jewelers perspective.

The man is just a Genius at his craft

This is a wonderful demonstration of Lenz's law . This demonstration should be done in physics classes when they cover electromagnetism .

Can't wait to see the big one! Silver is cool, but so is copper! :D

I looked up the electrical conductivity of sterling silver and it's slightly less than pure copper (96% vs. 97%) so the result was as-expected. Also, your sterling was pretty heavily tarnished (silver oxide) and that would further reduce your electrical conductivity. Even if it drops by 1% more as a result you'd notice that.

Brilliant, the "keg furnace"!

Fun to see all these techniques! Makes me want my own kiln.

I've seen people make penny sorting ramps using this effect by placing two small magnets at the end of a shallow ramp. When a copper penny rolls past the magnets it slows down enough that it drops off at the end of the ramp. The plated pennies fly right past them.

I think it might be fun to make a "hover" track. like a twisting turning trough track that a marble could roll down, but a short magnetic cylinder would "hover" down. not sure if you would need opposing magnets or it could just be copper.

Fun fact: In effect, the current in the conductive tube makes an image of the magnet inside the tube and around it that exactly works in opposition to the magnet's motion no matter which way it is oriented. Below the magnet the 'image-magnet' is repelling the falling magnet and above the image-magnet is attracting the falling magnet. We can see this because when the magnet is slightly ABOVE the tube before it fully enters, it is slower AND when the magnet is below the tube just exiting, it is also slower. There is a UKposts video of a guy that cooled the tube in liquid nitrogen, I believe, and the slowing effect is increased.

Awesome video. I can just imagine how this could be used in some carnival game to introduce some unexpected physics to throw people off :)

I have an "Anti gravity" table. I put things on it and they dont fall straight to the center of the earth. Really mysterious and fantastic.

Cool stuff, I wonder if cutting the coper and silver into segmented ribs and lining them up copper, silver, copper, etc would elicit a faster slow down or negate Lenz's law. would also a magnet rod with a copper rod core force Lenz's law to center the falling magnet in the tube.

Thank you for all you do you could make your subjects as complicated as you want

Very cool experiment. I didn’t expect the result but still very interesting.

Place the spherical magnet in some static position, optimally at an offset from the surface it lays on. If you proceed to attach either the hollow copper or silver cylinders to the end of some rotary tool such that the axis of rotation of the tool and the cylinder are equal, then proceed to place the cylinder attached to the rotary tool’s axis of rotation perpendicular to the surface that the spherical neodymium magnet lays upon, while intersecting with the center point of the magnet, then when imparting a rotational velocity on the cylinder in these conditions, should keep the sphere in the cylinder, so long as angular velocity remains at a certain level

The first experiment that you have in the video with the long thin walled copper tube is very interesting because of the longer time it takes for the magnet to drop through. This could be roughly timed by a second person with a stop watch. Then try placing cylindrical lead weights ( with same diameter of magnet) of various lengths (meaning they would have differing weights) onto one end of the magnet using double back sticky tape then drop it through the tube and time it again for each weight. I don’t know what will be the relation between speed versus the added weight. It might be interesting. As always magnets are very brittle and should always use safety goggles. Thanks.

Good for car shock absorbers or dampeners 👍👍 Imagine having those - smooth ride - long lasting unlimited ...

Great experiment. Thanks for sharing.

The cracking in the shell was likely from trapped moisture in the ceramic, you likely needed to let it dry for another few hours minimum before heating it

You should try to do a collab with Diresta. He *REALLY* could use your help with the casting process.

8:51 👈🏼 it looks phenomenal ! !

Cube magnet through both round and square tubes would be interesting 👏

Such an interesting departure from your normal fare! Believe it or not, in my all of my 67 years, I've never seen that demonstrated. It just goes to show that when you think you've seen everything, you find out that you haven't even begun. Keep up the good work and congratulations on yet another fascinating video.

It would be interesting if you could measure the weight of the tube while the magnet is falling through it and compare it to the individual weights.

Another brilliant video! Happy holidays from the UK to you and your family.

You are supporting children who are really interested in learning by doing Thanks.

I think this would work even better with smaller inner diameter of the tubes (more precission fit with the ball), so more magnetic field will penetrate tubes wall.

Does the wall thickness of the tube affect the rate of fall? Can you machine the outsides of the copper to say 1/16, or 1/8 inch and time the rate of fall? Reason I ask is a magnet holds harder on thick steel as compared to sheet metal. Also would be interested in the rate of fall in a gold tube, but that's an expensive experiment 😊 Great job, thanks for posting

Very interesting! I think that’s the same principle behind how an alternator in a gas powered car works. A metal piece is rotated inside of a thick band of copper wires which produces a current.

Small differences in distance makes a big difference in breaking power. Use the two silver tubes and place them exactly the same width apart as the copper tubes and roll it through them.

As an engineer I can see how Lenz's law could be applied into elevator technology. Think how much energy you could save! This would be great for mobile elevator systems to haul freight or even ore from mine shafts.

This was a super cool demonstration, I do a similar one in the physics classes I teach when I get to induced magnetic fields, unfortunately I'm limited to the thickness of copper that is sold at home depot as a result the slow down effect isn't quite as significant. Definitely is cool though with the spherical magnet too as you can do all sorts of rolling demos

Never knew this! I found the experiment to be very interesting! Thanks!

I thunk you should do it again with "purer" metal and answer all questions in the comments. This is a very nice phenomen and your video is very nice to watch!

Did you consider boring out the ceramic from the inside using some abrasive tool on the lathe, instead of sand blasting? I wonder if that would work well?

It would be interesting to stack the tubes, with copper on top, silver in the middle and copper on the bottom. I’m curious what it would look like falling through and if there would be a soeed change or not

That's great ! With the silver , you can make a nice bracelet.

When you spoke about molasses effect it made me think of gas suspension on those expensive cars

Does the clearance between the ID of the sleeve and OD of the sphere effect the drag time?

Would be interesting to align the N52 Sphere with another Bar Magnet while laying both Sphere, and Bar magnets stuck together on a flat surface, with the Bar Magnet set on the table so the narrow edge is oriented vertically to the plan of the table to squarely contact the Sphere's surface at the Equator. Then when both magnets are opposit pole attracted with aligned North/South use a Sharpie Permanent Marker to paint a black outlined line to show the Sphere's North & South Poles using a carpenters, or machinist square to draw with by rotating the Sphere while adding a black permanent marker line to outline the Sphere's Equator. Then using permanent marker stain the Sphere's nickel plate surface in two different colors such as Red/Blue or Red/Green to brightly display the Sphere's North/South poles. Then video record the drop of the color stained N52 Magnetic Sphere through the two metal tubes of Copper & Silver to record the N52 Sphere watching how the colorized North & South poles spin, or tumble in what observable slow motion different direction, or oscillating patterns when experiencing the two different metal's repulsive forces. After recording, use 91% Isopropyl alcohol and a tissue to clean off the marker stain from your N52 magnet Sphere's surface, restoring the magnets original nickel finish.

Yeah, I have seen it. I Havwe been knowing that for years now and the fist time that I saw few demonstrations of all kind, I just fell out of my chair. I think that cool is an understatement.

Addendum: To purify your sterling silver into pure silver, melt your sterling and pure the molten metal into deep water to make 'corn flakes' then dissolve out the copper with nitric acid, copper preferential reacts with the acid more than the silver. You tube should have videos describing this process in more detail. Looking forward to more videos, Thank you. - Ken

What happens if the clearance between the magnet and tube is reduced?

Nifty ! So, if copper had the best(slowest) result & it's known that silver has the best thermal & electrical conductivity, it would seem to be a contradiction to conclude that the silver was worse(faster) bc of its copper contamination. Yet I'd guess it does indeed have something to do with the alloy's crystal structures or something & perhaps other chemical or even QM aspects. Also, a good test would be to see just how significant wall thickness is, I always assumed the thicker the better but is that necessarily true & to what extent ?

I did this with a 3ft copper tube and if you turn the lights off you can see very small arcing, quite cool!

Nice work. I discovered this phenomenon 15 years ago using a magnet from a shake lite in a 4 ft. copper tube. It took 11 seconds to reach bottom. I started thinking it might be a good safety device for elevators & might produce a bit of power as well/

cool, is the final diameter of the silver tubes the same as the copper? also would a magnet that is closer to the inside diameter of the tube travel slower?

You could use Silver Plating process to make the silver more pure to see if the purity affects how much slowing occurs.

Love these type of videos, that are a bit more sciency. Would love to see more like this in the future!

WOW I wish I had so many toys to play with making the necessary parts. Neodymium magnets are very expensive too.

strange indeed. If you test the electrical resistance of the tubes from end to end with a multi-meter, is there any measurable difference in ohms?

What kind of sorcery witchcraft voodoo is this 😅

I'll be mentioning it to a good friend of mine, a young physicist who probably learned "lenz law" a long time ago, while I though much older only mastered basic math (lol). I thought of something else when you mentioned feeling the weight of the mag. as it fell--putting the tubes on a scale and observing the difference...if the increase is the weight of the magnet.

Thats a funky kool vise you hav there!

Sterling silver does not have as high of conductivity as pure silver. Pure silver is about 7% more conductive than pure copper. Stands to reason the sterling silver has lower conductivity than copper and therefore oppose the falling magnet less. Lenz's Law states that magnetically induced electric current (here in the tube around the circumferentially) would be circulating in a direction such that its self-generated magnetic field would oppose the change in magnetic field introduced by the falling magnet. Therefore we have the magnet's weight due to gravity pulling toward the ground while the opposing magnetic field force is directed upward. The net acceleration is a result of the vector sum of opposing forces divided by the mass of the magnet. a = ΣF/m. Notice the fall rate seems constant. This means the acceleration is zero and therefore the net force is zero - the weight is cancelled by the Lenz force if you will. The added weight you feel while the magnet is falling through the tube is exactly the weight of the magnet via the mechanism of the equally opposing magnetic force that originates in the tube. Hang the tube from a scale, then watch the total weight as the magnet falls through the tube. You will see the total weight increases by the magnet weight. If you could high speed film the insertion into the tube you'd see a very short range of negative acceleration where the magnetic sphere starts at freefall (~9.8 m/s/s) and decelerates down to a constant speed. I suspect, though never tested this....that once the entire sphere is within the tube, it has constant speed. Prior to that, the part of the spherical magnet outside the tube still has a component of its weight but that part of its weight is not countered by the opposing magnetic field until inside the tube. The action here is nature's attempt to counter change - to put things into their lowest energy state. BTW, this is not anti-gravity in any way whatsoever. Gravity is still very alive and well throughout this entire process 'cause you'd have to remove the planet from our general proximity by a very large distance to achieve an anti-gravity state. What's going on here is a balance of forces - one gravitational (we call it weight of a mass) and one magnetic - they oppose equally and oppositely resulting in zero net force. If this effect could turn gravity off, then the magnet would launch vertically upward as a result of an unbalanced force. Clearly that does not happen. I hope this is insightful and interesting. Retired physics professor wanting to share cool stuff that is not alway obvious to the casual observer. Cheers!!!