Making Anti-gravity tubes - Copper & Silver! - Lenz's law - Metal casting Experiment

In this video I will be making a set of silver and copper tubes to experiment with Lenz's law.

Casting equipment

3d printing FDM

3d printing Resin

Belt Grinder

Belt Grinder Accessories

Welding

Metal finishing tools

General

Some of my favorite tools of the year

Camera Equipment

All of the links above are affiliate links. This means that, at zero cost to you, I will earn an affiliate commission if you click through the link and finalize a purchase.

[robinson-foundry]

If you're interested in any of the tools or equipment I use and you want to help support the channel then don't forget to check out some of the affiliate links in the video description. Thank you for the support!

[mattlong]

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

[appliedengineering]

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.

[Toxicity]

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.

[rogerbarrett]

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.

[smartengineer]

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.

[robertlantz]

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.

[quixoticjedi]

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.

[jamesyoung]

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.

[PyroForge]

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.

[DemsRNutless]

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.

[mcwolfbeast]

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.

[murilovsilva]

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

[esurfrider]

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

[zetou]

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.

[BigRonRN]

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.

[StuffBudDuz]

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!

[unicornadrian]

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

[Fizzo]

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.

[letstrytouserealscienceoka]

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.