25 Facts About Magnets That Will Attract Your Attention

[00:00:00]You use magnets [music] every single day. They're in your phone, your car, and strapped to your refrigerator. But most of us treat magnetism like magic.

[00:00:11]It just works, and we never really actually question why. The real science behind them is genuinely strange. I'm Michael with List 25, and these are 25 wild facts about magnets.

[00:00:24]25. Space's deadliest magnets.

[00:00:27]Magnetars are a specific type of neutron star. And their magnetic fields are roughly a 100red billion times stronger than anything humans have ever built. If you got within a thousand km of one, that magnetic field would literally distort the chemistry of your atoms and kill you before any actual radiation hit you. In 2004, a magnetar halfway across the galaxy released a burst of energy lasting a fraction of a second. That tiny burst carried the same amount of energy our sun produces in [music] a quarter of a million years. It was so intense it actually messed with Earth's upper atmosphere. 24. The moving north pole. If you grab a compass and walk straight north, you won't end up at the geographic north pole. Magnetic north is currently drifting across the Arctic Ocean towards Siberia at about 55 km a year. It's moving so fast right now that airports are literally having to repaint their runway numbers and update navigation charts just to keep planes aligned correctly. So the difference between true north and magnetic north changes every single year depending entirely on where you're standing. 23.

[00:01:44]Blow torches kill magnets.

[00:01:46]Every magnet has a specific breaking point called the cury point. For a standard piece of iron, it's around 770° C. Below that temperature, all the tiny atomic magnets inside are lined up perfectly. But if you hit it with a blowtorrch, the heat [music] shakes those atoms so violently that the alignment totally collapses [music] and the magnetic field completely vanishes.

[00:02:10]You can remagnetize it later, but the heat kills it dead in the moment. This is exactly why leaving magnetized tools sitting in a baking hot car is a terrible idea. 22. Plastic fridge magnets.

[00:02:26]That flat takeout menu stuck to your refrigerator isn't actually a piece of metal. [snorts] It's a sheet of plastic loaded with millions of microscopic magnetic particles. Manufacturers align all those tiny particles while the plastic is still hot and soft. Once it cools and hardens, the magnetic field is permanently locked in place. You end up with a material that's flexible like plastic but sticks like iron. It's the same exact tech used for the magnetic strip on the back of your credit card.

[00:02:54]21. Silent MRI magnets. If you've ever been inside an MRI machine, you know they sound like a jackhammer, but that deafening noise has absolutely nothing to do with the main magnet. The sound comes from smaller internal coils rapidly snapping on and off during your scan. The massive primary magnet running the whole machine is completely [music] silent. It also never turns off.

[00:03:19]Shutting down an MRI magnet is incredibly expensive, so hospitals just leave them running non-stop. That's exactly why you have to take off your jewelry before walking into the room, [music] even if the machine looks like it's powered down. 20. Finger crushing magnets. Those tiny silver neodymium magnets you buy at the hobby store seem perfectly harmless, but scale them up and they become a massive safety hazard.

[00:03:48]Large neodymium magnets can snap together so fast [music] and with so much force that they will easily crush your fingers. There are genuine medical reports of people needing surgery to separate the magnets from their bones.

[00:04:02]If they collide at full speed, the impact is so violent, the [music] magnets themselves will shatter and send sharp shrapnel flying everywhere. They are strictly for engineering, not messing around. 19. Magnetic military weapons.

[00:04:20]The military has rail guns that fire projectiles at Mach 6 without using a single drop of gunpowder. They use massive electromagnetic forces to accelerate a solid chunk of metal down a track fast enough to punch straight through thick steel. Generating that kind of power actually isn't the hard part. The real engineering nightmare is that the electrical current is so intense it physically shreds the barrel after just a few shots. Researchers have spent decades trying to build a rail gun that doesn't destroy itself every time you pull the trigger. 18. Pigeon GPS beaks.

[00:04:58]Homing pigeons can be dropped in a completely random location hundreds of miles away and fly straight home. They pull this off because they have tiny magnetic crystals physically embedded inside their beaks. These crystals constantly react to Earth's magnetic field, acting like [music] a built-in biological GPS.

[00:05:17]Scientists figure this out by strapping artificial magnets to the birds to scramble the signal, which caused them to immediately get lost. Now researchers are studying how to copy this exact biological trick to build satellite free navigation systems. 17. Secret passport scans.

[00:05:34]Modern passports have a magnetic strip hidden right inside them. It uses the exact same tech as your debit card, [music] but instead of holding a bank account number, it holds all your biometric data. Every single time Border Patrol swipes or scans your passport, a magnet reader is pulling that hidden data and running it against government databases in [music] real time. We think of passports as just ink and paper, but they're actually working as high-tech magnetic storage drives every time you cross a border. 16. Spiky liquid [music] magnets.

[00:06:09]Ferrofluid is a crazy black liquid loaded with magnetic nano particles. If it's [music] just sitting in a bottle, it looks like thick ink. But the second you hold a strong magnet near it, the liquid instantly grows sharp. Geometric spikes that map out the invisible magnetic field. Move the magnet and the spikes follow. NASA actually invented the stuff back in 1963 because they needed a way to pull rocket fuel into engines in zero gravity without using mechanical pumps. Now, we use it in high-end speakers and experimental medical treatments and in the queue for Avatar Flight of Passage at Disney's Animal Kingdom, but not if you use Lightning Lane. You'll you'll skip it.

[00:06:51]It's in the the section where you have the giant avatar floating in the tank.

[00:06:56]It's really cool. It's actual ferrofluid.

[00:06:59]15. The first compasses.

[00:07:02]The earliest compasses weren't made of metal. They were just naturally magnetic rocks called load stones. Chinese navigators figured out how to use them a thousand years ago, and the tech eventually spread to European sailors exploring the ocean. But here's the crazy part. For roughly 1500 years, no one had any idea why the rocks actually pointed north. People seriously thought the North Star or giant magnetic mountains were pulling the rocks. It took until the year 1600 for a physicist to finally realize the Earth itself [music] is just one massive magnet.

[00:07:38]14. Electric car magnets.

[00:07:42]A standard gas engine makes your car move by literally exploding fuel to push heavy metal pistons [music] up and down.

[00:07:48]It's loud, hot, and incredibly complex.

[00:07:52]Electric cars do the [music] exact same job just by passing a current through a magnetic coil. That's why electric motors are much more efficient. A standard gas engine loses over 60% of its energy to heat and noise. An electric motor converts over 90% of its electrical power straight into pure motion simply by using clean magnetic forces. 13. Floating Japanese trains.

[00:08:17]The Japanese magv train doesn't have wheels. It uses superconducting magnets to literally levitate above the track.

[00:08:25]Because the train never physically touches the guideway. There's zero friction. The only thing holding it back is air resistance. In 2015, a test version hit an unbelievable 603 km per hour. China actually runs a commercial version in Shanghai right now that hits over 430 km/h, turning what should be a long commute into a 7-minute ride. 12.

[00:08:52]The monopole mystery.

[00:08:55]Every magnet has a north and a south pole. If you snap one in half, hoping to get a separate north piece and a south piece, it won't work. You just get two smaller magnets, each with its own brand new north and south pole. This is totally different from electricity, where you can easily isolate a positive or negative charge. Physicists have been desperately hunting for a single isolated magnetic pole since the 1930s.

[00:09:22]They've never found one. Either magnetic monopoles don't exist or they're hiding incredibly well. 11. Phone magnets.

[00:09:33]When you hear the word magnet, [music] you probably picture the alphabet letters on a fridge. But the smartphone in your pocket has anywhere from [music] 30 to 60 magnets packed inside it right now. Magnets make your phone vibrate.

[00:09:46]They stabilize your camera lens so your photos don't come out blurry. The tiny speaker pumping sound to your ear only works because a magnetic coil is vibrating a membrane thousands of times a second. You're literally carrying a pocket full of high-tech magnets everywhere you go. 10 scrambled credit cards.

[00:10:07]That dark stripe on the back of your credit card is just a layer of [music] magnetic particles baked into the plastic. Your bank account info is written on that stripe through a very specific magnetic pattern. When you swipe it at the register, a reader translates those microscopic magnetic fields back into numbers. This is exactly why throwing a strong magnet in your purse or pocket [music] can completely ruin your cards. It scramles the magnetic pattern like an old cassette tape. [music] Hotel key cards use the exact same tech, which is why your room key keeps dying if you hold it next to your phone. Nine.

[00:10:45]Extracting eye shrapnel.

[00:10:48]If you get a piece of metal stuck in your eye, surgeons will sometimes use a high-powered handheld magnet to pull it out without making a single [music] cut.

[00:10:56]Because the eye is completely soft tissue, a strong enough magnetic field can safely drag the metal fragment right to the surface. It requires crazy precision and only works for specific magnetic metals. Duh. But it's one of the least invasive surgical options they have. I mean, I can't even put in eye drops without blinking aggressively. If you had the choice, are you trusting a giant magnet in your eye, or are you telling the doctor just to use [music] a scalpel? Let me know down below. Eight, your magnetic brain. Every time you think, move, or breathe, the neurons in your brain fire tiny electrical currents. Because moving electrical charges automatically create magnetic fields, your brain is constantly generating [music] a measurable magnetic aura. Though it's incredibly weak, roughly a billion times weaker than a cheap fridge magnet. To actually measure it, doctors have to use [music] machines cooled to near absolute zero inside heavily shielded rooms just to block out the Earth's background interference.

[00:12:00]But technically speaking, your brain isn't just an electrical organ. [music] It's a fully functioning magnetic one, too.

[00:12:07]Seven. Bacteria compasses.

[00:12:10]Certain types of bacteria naturally grow microscopic magnetic [music] crystals right inside their own bodies. They link them together to form a tiny internal compass needle. The Earth's magnetic field physically grabs that internal chain and steers the bacteria toward the low oxygen environments they need to survive. Now, scientists are trying to hijack this biological trick. They want to attach these natural bacteria magnets to cancer [music] drugs and use external magnets to steer the medicine precisely into tumors, totally bypassing healthy tissue. Six, navigating salmon. Salmon are born in rivers, spend years swimming thousands of miles across the open ocean, and then somehow find their way back to the exact same stream to reproduce. They pull this off by literally sensing the Earth's magnetic field. Researchers figured out that the specific magnetic signature of the stream where they're born gets permanently imprinted into their brains.

[00:13:08]When it's time to head home, they use that magnetic memory as a target, tracking an invisible signal across thousands of miles of open water. Five spinning magnets create power. Whether you're looking at a nuclear plant, a wind turbine, or a massive hydroelectric dam, they all generate electricity the same way. They spin magnets inside wire coils. The energy source just provides the brute force to spin a turbine. That turbine spins the magnets. The magnets create [music] an electric current and that current goes straight to your house. Michael Faraday figured this out back in 1831. [music] And almost 200 years later, our entire modern electrical grid is still built entirely on that one simple trick. Four.

[00:13:55]Earth is a magnet. The planet we live on is just one giant magnet. And its magnetic field stretches thousands of miles out into space. That invisible field acts like a massive protective shield that bounces deadly solar winds right off [music] our atmosphere.

[00:14:12]Without it, the sun would literally strip our atmosphere away, which is exactly [music] what happened to Mars billions of years ago. Mars lost its magnetic field when its core cooled down and stopped moving. Our core is still churning molten iron, keeping that shield up and keeping us alive. Three magnetic cows.

[00:14:33]Scientists looking at Google Earth satellite images notice something incredibly weird. Herds of cows all over the world naturally align their bodies facing north to south when they're grazing or resting. Sunlight and wind direction had absolutely nothing to do with it. The cows are literally syncing up with the Earth's magnetic field. We know this for a fact because when cows graze directly under high voltage power lines, the electrical interference scramles the local magnetic field and the herd immediately loses its alignment.

[00:15:06]Two magnetic plant roots.

[00:15:09]Gravity isn't the only thing pulling plant roots down into the dirt. They're also highly sensitive to magnetic fields. Scientists discover that hitting plants with different magnetic fields actually changes the direction the roots grow. The magnetic forces shift the hormones inside the plant, completely hijacking its internal navigation system. If researchers can figure out how to fully control this, they could force crop roots to grow deeper during severe droughts or spread out wider to find better nutrients. One, everything is magnets.

[00:15:43]Most of us think we can't walk through walls because atoms [music] are packed tightly together like bricks. But atoms are mostly just [music] empty space. The real reason you can't push your hand straight through a wooden table is pure electromagnetism.

[00:15:59]The electron clouds on your hand and the electron clouds on the table aggressively repel each other. When you press down, you aren't feeling atoms physically touching. You're feeling a localized magnetic force pushing back against you. Magnetism is literally the only thing stopping you from falling through the floor. Magnets run almost every piece of technology you own, yet remain one of the strangest forces in the universe. For more science that feels fake but is totally real, check out our video, 25 of the most bizarre facts about science. As always, I'm Mike Estin. Stay curious and I'll see you in the next