# Dustin

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1. ## 3 Questions About Electromagnets

Well, thank you for the information! Ultimately, I'd love to try to make a 12" plate that's magnetic. I'll have to consider your suggestion. This makes sense that it would be weaker. But if I apply enough turns of wire and a strong of enough battery for the current, I wonder if those field lines will close over a 12" plate? Thanks!
2. ## 3 Questions About Electromagnets

Hello, I'm sure many of you have seen examples of a DIY electromagnet, such as wrapping copper wire around a nail or bolt and hooking the ends to a battery. I have 3 questions about this. 1. What material, or metal, must be used for the object? In the examples of nails and bolts, are they steel? Iron? What characteristic must be true about that object? (ferro-magnetic? or whatever?) 2. If you had a plate of some kind, like an oven pan (something 1/4" deep or more) and wrapped the copper wire around it, could you make a plate or pan magnetic? It doesn't HAVE to be a nail or bolt, right? I think it'd be cool to make an electromagnetic surface or plate of some kind! 3. What governs the strength of the magnet? The size (power) of the battery or the number of turns of wire? Thanks, Dustin
3. ## 4 Questions About Lenz's Law Experiment

Hello, I have four questions. As it stands now, I don't have the necessary materials to test this myself, which is how I'd prefer to learn the answer. I still plan on doing this experiment for fun once I can acquire the necessary components. This deals with Lenz's Law. My goal is to maximize the time it takes for an object to fall through a tube. 1) Most folks demonstrate Lenz's Law by dropping a magnet down a copper pipe. From my understanding, the relative motion of the magnet, to the copper pipe, is responsible for creating Eddy currents, which, in turn, provide an opposing force on the magnet as it falls. My first question is this: Does spinning the copper tube create more Eddy currents, or opposing force? Would it slow the magnet's descent even more? 2) Regardless of the answer to my first question, if that same copper tube is spinning and you drop a magnet down into it, that magnet would spin as well, yes? (I've seen a YouTube video of ring magnets on the outside of a copper tube spinning as the copper spun) Here's my main question: If you dumped a handful of tiny magnets down the spinning copper tube, would all the tiny magnets spin individually and simply keep falling? Will there be any centrifugal force applied onto the tiny magnets so that they start moving outward towards the walls of the copper tube as they fell? Do magnetic fields create, and impose, vortex/helical/centrifugal forces on conductive objects? Or do they simply spin and stay mostly in the center of the copper tube as they fall? 3) Now suppose the experiment in reverse. I have a 'tube' of neodymium magnets. (Probably several rings stacked up on each other, which can be expensive) and I dropped a copper object down the magnet tube. I understand that the effect will still occur; it will still fall slowly. But copper, alumimum, and other metals are diamagnetic. Does that dampen the opposing force created by the Eddy currents, or have little to no effect at all? It's the conductivity of copper/alumimum that is slowing it, not whether or not it's ferromagnetic or diamagnetic, right? 4) Last question. How does the copper tube's wall thickness affect this experiment? Do thicker walls generate more opposing force on the magnet, thus, it falls even slower? Or would thinner walls make it fall slower? I just assume thicker walls would make for more resistance, thus, make the object fall slower. I hope I made sense with my questions. Copper can be...expensive, so I'll test this out soon enough. Maybe I can make an aluminum foil tube? Thanks! Dustin
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