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Dropping a neodymium magnet through a copper pipe

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Dropping a neodymium magnet through a copper pipe

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Do not try at home without help/permission.

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There are quite a few neodymium magnets falling through copper pipes on the internet, but we can still understand why this demonstration video is making the rounds: it's just so cool looking! We've covered the phenomenon of magnetic damping before:

When a magnetic field moves through a conductor a current called an Eddy current is induced in the conductor due to the magnetic field's movement. The flow of electrons in the conductor creates an opposing magnetic field to the magnet which results in damping of the magnet and causes heating inside of the conductor similar to heat buildup inside of power cords. The loss of energy used to heat up the conductor is equal to the loss of kinetic energy by the magnet.

And a note of caution if you decide to try this, these magnets are not for unsupervised children. In fact, everyone should be careful:

Neodymium magnets larger than a half inch are very strong and should be handled with extreme care since they can be dangerous. It is best to stick with neodymium magnets of quarter inch diameter or less.

Want to know more? Look up Lenz's Law and watch Veritasium's Derek Muller demonstrate how this phenomenon is related to English scientist Michael Faraday and the first electric generator, created with a magnet and a coil of wire in 1831:

Physics! Another must-watch magnet-doing-magic-like-things-video comes from the Ri Channel: Levitating Superconductor on a Möbius strip.

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Dropping a neodymium magnet through a thick copper pipe

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There are quite a few neodymium magnets falling through copper pipes on the internet, but we can still understand why this demonstration video is making the rounds: it's just so cool looking! We've covered the phenomenon of magnetic damping before: When a magnetic field moves through

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Did the magnets change how the batteries moved?

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Lay out a 'race track' of tinfoil, attach two round neodymium magnets to the ends of an AA battery x2 (or more) - the polarity of the magnets matters, so experiment to see how your vehicle behaves (or doesn't) - then race the little vehicles down the track! If you have two different sizes of magnet on each end of the battery, they'll do donuts, as shown in the Magnetic Games video above.

These little race cars are simple homopolar motors. From wikipedia:

The homopolar motor is driven by the Lorentz force. A conductor with a current flowing through it when placed in a magnetic field which is perpendicular to the current feels a force in the direction perpendicular to both the magnetic field and the current. This force provides a torque around the axis of rotation. Because the axis of rotation is parallel to the magnetic field, and the opposing magnetic fields do not change polarity, no commutation is required for the conductor to keep turning.

Homopolar motors make for fun experiments. Please note these neodymium magnet hazards to help practice safe & smart science. This video demonstrates a basic homopolar motor using an AA battery, neodymium magnets, and a variety of copper wire shapes:

What other ways can you shape the copper wire? Try this next: How to make the world's simplest electric toy train, and don't miss Electromagnetic Induction.

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How to make simple homopolar motor 'race cars'

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Lay out a 'race track' of tinfoil, attach two round neodymium magnets to the ends of an AA battery x2 (or more) -- the polarity of the magnets matters, so experiment to see how your vehicle behaves (or doesn't) -- then race the little vehicles down the track!

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How did they use push AND pulls to help the marble get to the end?

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Kapla blocks, marbles, steel ball bearings, a few dominos, sticks, and magnetic neocubes or buckyballs power this incredible series of elegant and surprising Rube Goldberg or Pitagora-style chain reactions. An instant classic with lots of surprises. From Kaplamino:

In this project, I use those little magnets that can be used to make cubes and others geometric figures...

It's really impressive how many tricks you can do with that, at the beginning I didn't think that I could make a whole project based on those magnets, but finally, it was pretty easy and I think there is still lots of cool tricks to discover !

I like this kind of video when I can't do what I want, I'm forced to think of tricks with magnets in that case. It's the opposite of my video "Random screen link" when I just build all the thing that come to my mind, constraints are good for the creativity it allows to find original tricks that no one has thought (I think, because I've never seen something like this on youtube).

This site is chock full of Rube Goldberg Machines, but incorporating simple materials in such a limited way makes these chain reactions super fresh. We've never tricks like these before either!

Check out more marbles, more magnets, and more chain reaction videos.

via Reddit.

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Magnets & Marbles, Kaplamino's Pitagora-style chain reactions - The Kid Should See This

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Kapla blocks, marbles, steel ball bearings, a few dominos, sticks, and magnetic neocubes or buckyballs power this incredible series of elegant and surprising Rube Goldberg or Pitagora-style chain reactions. An instant classic with lots of surprises. From Kaplamino: In this project, I use those little magnets that can be used to make cubes and others...

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http://studyjams.scholastic.com/studyjams/jams/science/forces-and-motion/force-and-motion.htm

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http://www.eduplace.com/kids/hmsc/activities/simulations/grk/unitf.html

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http://www.scienceunleashed.ie/Games/scooter.swf

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http://studyjams.scholastic.com/studyjams/jams/science/forces-and-motion/fgravity-and-inertia.htm

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http://thekidshouldseethis.com/post/a-fidget-spinner-in-space

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http://resources.hwb.wales.gov.uk/VTC/identify_forces/eng/Introduction/act1.swf

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http://studyjams.scholastic.com/studyjams/jams/science/forces-and-motion/acceleration.htm

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http://studyjams.scholastic.com/studyjams/jams/science/forces-and-motion/simple-machines.htm

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http://studyjams.scholastic.com/studyjams/jams/science/forces-and-motion/inertia.htm