A new study suggests that humans can subconsciously sense Earth's magnetic field. While this capability, called magnetoreception, is well known in birds and fish, there is now evidence that our brains are also sensitive to magnetic fields. The researchers from Caltech and the University of Tokyo measured the brainwaves of 26 participants who were exposed to magnetic fields that could be manipulated. Interestingly, the brainwaves were not affected by upward-pointing fields. From Science News:
Participants in this study, who all hailed from the Northern Hemisphere, should perceive downward-pointing magnetic fields as natural, whereas upward fields would constitute an anomaly, the researchers argue. Magnetoreceptive animals are known to shut off their internal compasses when encountering weird fields, such as those caused by lightning, which might lead the animals astray. Northern-born humans may similarly take their magnetic sense “offline” when faced with strange, upward-pointing fields...
Even accounting for which magnetic changes the brain picks up, researchers still don’t know what our minds might use that information for, (Caltech neurobiologist and geophysicist Joseph) Kirschvink says. Another lingering mystery is how, exactly, our brains detect Earth’s magnetic field. According to the researchers, the brain wave patterns uncovered in this study may be explained by sensory cells containing a magnetic mineral called magnetite, which has been found in magnetoreceptive trout as well as in the human brain.
"Transduction of the Geomagnetic Field as Evidenced from Alpha-band Activity in the Human Brain" (eNeuro)
"Evidence for a Human Geomagnetic Sense" (Caltech) Read the rest
Remember that school-room lesson on invisible forces where the teacher sprinkles iron filings over a sheet of paper that is placed over a magnet? Here's a complete upgrade. Watch these magnetic field patterns in 3D, created when magnetite sand is thrown on magnets – some of them bouncing on a small trampoline – and shot in slow motion. Beautifully captivating.
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A team at MIT’s Department of Mechanical Engineering and Department of Civil and Environmental Engineering have created a set of foldable, 3D printed robots that are doped with magnetic particles that are precisely aligned during printing; when triggered by a control-magnet they engage in precise movements: grabbing, jumping, rolling, squeezing, etc.
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MIT researchers designed and 3D-printed an array of soft, mechanical critters that are controlled by waving a magnet over them. The shapeshifters that fold up, crawl, grab things, and snap together into intricate formations may someday lead to new kinds of biomedical devices. For example, one of the devices "can even be directed to wrap itself around a small pill and carry it across a table." From MIT News:
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“We think in biomedicine this technique will find promising applications,” says (MIT mechanical engineer Xuanhe Zhao.) “For example, we could put a structure around a blood vessel to control the pumping of blood, or use a magnet to guide a device through the GI tract to take images, extract tissue samples, clear a blockage, or deliver certain drugs to a specific location. You can design, simulate, and then just print to achieve various functions.”
In addition to a rippling ring, a self-squeezing tube, and a spider-like grabber, the team printed other complex structures, such as a set of “auxetic” structures that rapidly shrink or expand along two directions. Zhao and his colleagues also printed a ring embedded with electrical circuits and red and green LED lights. Depending on the orientation of an external magnetic field, the ring deforms to light up either red or green, in a programmed manner.
The YouTube channel of Magnetic Games ("all the ways to have fun with magnets") posted high-powered neodymium magnets with names like "The Death Magnet" and "Big Magnet" colliding with one another in high-FPS slo-mo footage. [via] Read the rest
YouTuber NightHawkInLight got his hands on some thick copper plates and some neodymium magnets, then showed some of the strange ways the two materials interact. Read the rest
This essential purchase is only a dollar, but you have to pay shipping: a 1.25" magnet featuring a suave cartoon whale saying "WHALE HELLO." (Amazon) Best buy a dozen, then, just to be sure. We've been arguing all day about whether this is better than the "snailed it" magnet, and, frankly, things are getting kind of heated.
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Roman De Giuli created MATEREALITY, his latest in series of abstract films of chemical and physical reactions shot in extreme closeup. Read the rest
YouTuber Brainiac75 got a lot of questions about the possible dangers of a supermagnet affecting the iron in his blood, so he did an experiment with real blood. Read the rest
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.
• Will a Levitating Gyroscope Spin Forever in a Vacuum Chamber? (YouTube / The Action Lab) Read the rest
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.
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In March, brand-new Twitter account @SciSupport_BN mysteriously answered science questions, many of which had gone unanswered for years. The real fun started when Bill Nye himself filmed the replies. Read the rest
Hyperloop One engineers demonstrate the power of maglev using spinning arrays atop a copper plate. Despite weighing over 100 pounds, the gadget floats and could hold considerably more weight. Read the rest
YouTuber Brainiac75 suffers for science by taking a viewer request to touch the spikes formed by exposing ferrofluid to an extremely powerful neodymium magnet. He also shares some history of the substance. Read the rest
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