Derek Muller takes us inside one of the most powerful magnets on Earth — and makes it feel like a magic show. His coverage of the 45 Tesla magnet at the National High Magnetic Field Laboratory in Tallahassee isn't just science education; it's a demonstration of how magnetic fields reshape matter itself.
The Strongest Magnet on Earth
Muller opens with a claim that sounds almost hyperbolic: "this is the world's strongest magnet capable of sucking objects in generating electric current." He's not exaggerating. The magnet creates a field of 45 Tesla — nearly a million times Earth's magnetic field, which sits at just 0.00005 Tesla. This isn't a party trick; it's a research instrument used for materials science and condensed matter physics.
The design is surprisingly elegant. As Muller explains, "to achieve this field the magnet consists of an outer superconducting magnet and an inner resistive magnet" — two different technologies working together to generate something none could do alone. The maximum field occurs in a narrow cylinder only about a centimeter tall, but the experimenter's platform extends well beyond that.
This is what gives the 45 Tesla magnet its nickname: the "fringe field" extends far beyond the bore itself.
When Matter Meets Magnetism
The most visually striking part of Muller's coverage involves ferrofluid — a suspension of nanoscale magnetite particles coated in surfactant. He describes watching it develop parallel ridges even meters away from the magnet, then form spikes as they align with the field. This isn't just pretty; it's a window into how microscopic magnetic particles behave.
Muller also demonstrates something that many viewers have never considered: most materials are either magnetic or non-magnetic depending on their electron configuration. "Only some materials are magnetic," he explains, "electrons are essentially tiny magnets but in most atoms they are paired up one pointing one way and the other pointing the opposite way so their fields cancel out." This is a surprisingly clear explanation of why most matter isn't ferromagnetic — most electrons cancel each other out.
The etymology section adds nice texture: magnetite was first discovered in magnesia, Greece, giving us the word "magnet" itself. It's the kind of historical context that makes science feel human.
The Real Magic: Lenz's Law
Perhaps the most entertaining segment involves dropping metal plates through the magnetic field. Muller frames Lenz's law with characteristic directness: "I like to think of lens's law as the no you don't law because whatever you try to do nature acts to oppose you."
This is genuinely clever physics communication. When a plate falls toward a North magnetic pole, induced currents create their own North pole — repelling and slowing the descent. Muller demonstrates this repeatedly with aluminum cylinders, volleyballs wrapped in aluminum foil, even projectiles fired through the field at 45 Tesla. The projectile data shows how "as the projectile enters the magnetic field the induced Eddy currents rotate the projectile so it remains oriented along the magnetic field lines" — minimizing flux change.
The LED lights embedded in some projectiles light up depending on which direction the field is pointing, showing induced current changing in real time.
Levitation and Diamagnetism
The superconductors section demonstrates levitation through flux trapping: "below its critical temperature most of the material has zero electrical resistance which means if you bring a magnet close to it currents will be induced to oppose the change in flux and since it's a superconductor those currents can persist indefinitely."
But it's the diamagnetism section that may surprise viewers most. Most substances — water, strawberries, humans — are actually repelled by strong enough magnetic fields. "Water is a good example of this in the presence of the external field the water molecules become opposing magnets effectively and so they are repelled." This explains why Muller could show a strawberry being levitated with a 31 Tesla magnet: the water content makes produce diamagnetic, creating an indent in the field.
Google's Sustainability Plug
The video includes a segment sponsored by Google, connecting magnetic fields to electric vehicle motors and sustainability. The company has matched 100% of its electricity use with renewable energy since 2017. Muller personally endorses Project Sunroof, which uses Google Maps data to model rooftop solar potential.
"I like to think of lens's law as the no you don't law because whatever you try to do nature acts to oppose you"
The sponsorship is unobtrusive and actually relevant — electric vehicle motors do require magnets to work.
Counterpoints
Critics might note that the video sometimes prioritizes visual spectacle over deep explanation. The experiments are entertaining but don't fully explain why strong magnetic fields matter for fundamental physics research. Also, the Google segment feels slightly inserted rather than organically integrated.
Bottom Line
Muller delivers what every science communicator aims for: making extreme phenomena feel accessible. His strongest move is using Lenz's law as "the no you don't law" — a framing that makes electromagnetic induction feel like a personal relationship with the universe. The 45 Tesla magnet footage is genuinely impressive, and his explanation of diamagnetism in water could change how readers think about everyday objects. The biggest weakness? This feels more like a performance than a primer on why high magnetic fields actually matter for materials research.", "json": "