These bags of Tetris-branded magnetic tetrominoes don't look much good (it's obviously just a rubbery sheet with the shapes stamped out) but they are dirt cheap (49 for $9) and the street (you) will find its own uses. (very previously)
Are there any good magnetic tetrominoes? As in: each "pixel" a cube rather than millimeter-thick. Read the rest
The Action Lab took a maglev gyroscope and placed it inside a sealed chamber to see what happens to a levitating gyroscope in a vacuum.
A lot of people took issue with the experiment's setup and explanation, but it's interesting nonetheless. He responded to those concerns:
Hi everyone! I see a lot of comments that mention it will stop because of gravity. A lot of people said that in my pendulum video also. But remember that gravity doesn't "slow things down." The only reason we associate gravity with slowing things down is because it pulls things toward the earth and they hit the earth and the friction causes it to stop. So friction is the stopping force, not gravity. But you are right, gravity does play a role here that I didn't mention in the video. That is that it causes precession in the gyroscope. Since it never started out initially straight up, gravity does make the gyroscope tip over eventually. This may be even a larger factor than the magnet friction I talked about.
As a kid, I grew up near minutes from the beach and many times saw grownups meticulously sifting through the sand with a metal detector. I imagined they were pulling up diamond rings and pirate's gold. My dad assured me they weren't, though I suspect he just didn't want to buy me a metal detector.
In any case, these magnet fishing hobbyists have them beat.
By dropping a very strong magnet underwater, history buffs "WW2 Wendal" fish their local lochs and rivers for valuable metal objects. They primarily explore WW2 sites for discarded war artifacts but often reel in non-military items such as stolen safes and, well, junk. Sometimes they find nothing at all but, judging from their videos, that doesn't break their spirit.
Neodynmium magnets and a high speed camera? It turns out it is, as the kids say, oddly satisfying. I was practicing with some macro shots with the Chronos high speed camera, using LED lighting and filming at around 4000 frames per second. I dropped some hard drive magnets and noticed the magnets behaved very oddly and unpredictably.
I’ve been playing with my FEEL FLUX for weeks and its hit rate in the amazement department is 100%.
Each time you drop the metal ball through the copper tube you’d expect it to zip out the other end but instead, it lazily creeps from one end to the other and dribbles out into your waiting hand.
A “Silent Catch” is what happens when you toss the ball into the FF and it slowly glides down the sides without making contact with it. I have to say that it’s satisfying and magical every time I pull off the maneuver.
As the ball glides down the tube, the magnetic field changes inside the metal wall and when this happens, a bit of voltage is created. This reaction is not unlike a tiny, temporary battery and is called an electromotive force. The movement pattern of the voltage moves down with the ball and looks like this:
What could be simpler?
The tube’s material is an electrical conductor and drives current around in circles as the ball descends. The scientists at my laboratory tell me that when this happens, a second magnetic field is created that opposes the downward motion of the magnetic ball. The ball wants to fall through the tube at 9.8 meters per second but the field wants to halt it and of course, gravity wins in the end. And here’s the crazy part – the faster the initial downward motion, the more powerful the slowing force becomes. Read the rest
Here's cobrakiller2000's homemade Levitron-style magnetic top. He says:
The only non-electric way that I know off to get a magnet fully levitating over a magnet and with nice elevation too. Looks way cool and is just overall a beautiful invention in my opinion. Was hard to pull this off. I struggled for weeks before I got it levitating - very delicate system. Yes, gyroscopic forces keep it from tipping over and therefore keeps it in repelling mode as long the rpm are high enough.Read the rest
Joe Hanson from It’s Okay to be Smart and Dianna Cowern from Physics Girl met up with Joe DiPrima of Arc Attack to sear aluminum cans apart with a powerful electromagnet.
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Watch a soda can rip itself apart in a fiery explosion at 11,000fps with a Phantom high speed camera. Running a current through a coil, produces an electromagnet. Turn up the voltage in this experiment, and make that current strong enough, and your electromagnet can rip a soda can in half. Or rather, make the can rip itself in half!
Kaplamino made this delightful Rube Goldberg-esque demo using magnets and steel balls.
Brainiac75 made a pair of wooden tools that he uses to separate and stack large neodymium magnet discs. I've pinched my fingers quite a few times with tiny neodymium magnet discs and have learned to respect them. These big ones are very dangerous. You could easily lose a finger if these magnets were to smack into one another. Please get some thick gloves, Brainiac75! Read the rest