By manipulating the orientation of hydrogen atoms, magnetic resonance imaging machines capture cross-sections of an organism to build a 3D reconstruction of its anatomy.

Certain objects are magnetic because their electrons' magnetic moment—an intrinsic quantum property—align within the object in specific patterns.

How do brain scans work?

There's only one thing in our solar system sophisticated enough to study itself: the human brain. But this self-investigation is challenging because a living brain is shielded by skull, swaddled in tissue, and made up of billions of tiny cells. How do we study living brains without harming their owners? Two experts explain how the various techniques like EEGs, fMRIs, and PETs work in this TedEd talk.

Just as shadows can reveal the shapes of obstacles blocking visible light, computed tomography scanners create 3D internal images by measuring X-ray blockage.

Learn why magnets, like statically charged balloons, can deflect water

While the oxygen atom in water molecules strongly attracts hydrogen's electrons—producing an uneven charge distribution that pulls water toward balloons that have been rubbed against surfaces—the presence of a magnetic field alters the path of these electrons, which produce their own tiny magnetic fields. The interaction of these fields repels water away from magnets, making it diamagnetic.

Hacking the body for a future that didn't happen

Journalist Adi Robertson experimented with one of the most accessible biohacks: magnets. Having a tiny magnet in their right ring finger meant they could sense magnetic fields, attract small metal objects, and more. But magnets weaken over time, eroding this new sense. Such implants do more than offer a new way of interacting with the world, they also pose new complications, such as the inability to get an MRI.

Ultrasound machines emit and receive high-frequency sound waves to construct images of the body's interior, with differences in the penetrating power of different frequencies allowing medical professionals to identify different structures.

Lasers, semiconductors, medical imaging, and atomic clocks rely on quantum mechanics

Semiconductors, crucial in electronics, operate based on quantum superposition. Lasers use stimulated emission, a quantum process, and MRI machines leverage the quantum spin of hydrogen atoms for imaging. Atomic clocks measure time with unprecedented precision using quantum transitions.

Measurements of an electron’s magnetic moment help test the Standard Model

A particle’s magnetic moment quantifies how it responds to the presence of an external magnetic field. An electron’s value can be measured down to 14 decimal places, with certainties in the first 12 allowing it to be used to assess the accuracy of predictive models.

Radio waves are used in broadcasting, weather radar, telecommunications, and GPS

Its ability to bend around obstacles and reflect off the ionosphere—an electrified layer of Earth's upper atmosphere—allows this type of light to travel long distances without damaging living things due to its low energy. MRI scanners, WiFi, and Bluetooth technologies are also applications of this form of light.

Cyclotrons move particles in spiral paths of increasing radius

After particles are injected into the center of the device, an alternating electric field and a constant magnetic field energize the particles as they spiral outward toward a target. Cyclotrons are common in hospitals that perform molecular imaging, which relies on radioactive components that decay within hours.

The movement of molten metal around Earth's inner core creates the planet's magnetic field, whose north and south poles do not align with the planet's geographic poles.

Metal detectors identify induced magnetic fields in conductive objects

A changing magnetic field in a transmitter coil causes an electric current to be produced in materials that conduct electricity. This current generates its own magnetic field, which can be detected by a receiver coil and transmitted to a control box, which identifies the presence and depth of an object.

Temperatures colder than Pluto can allow electricity to flow resistance-free

Since its discovery in 1911, applications of superconductivity have made MRI machines and maglev trains possible due to quantum effects at extreme temperatures. These effects are modeled as electrons cooperating in pairs and flowing more efficiently.

Holograms are produced by shining light through recordings of interference patterns

When one half of a split laser beam that was reflected off the surface of an object recombines with its other, unreflected half, the two produce an interference pattern that becomes etched onto holographic film. When light shines through the back of the film, it reacts with the pattern to create the reflected light, projecting the original object.

Medical imaging allows 3D printers to create patient-matched devices

With imaging data on a person's anatomy, external prostheses and implants, such as cranial plates or hip joints, can be custom-printed to better match a patient's body. Fabrication of porous structures can promote bone growth, leading to longer-lasting implants.

PET scans create images of the body by detecting light emitted from the annihilation of matter and antimatter, with the latter produced by custom chemicals containing radioactive atoms.

Magnetic material in rocks provides evidence of flips in Earth's magnetic field

Volcanic rocks can lock in the direction of Earth's magnetic field as they cool, making them natural recorders of magnetism. Dating rocks and seeing the changing orientation of their magnetic field helps construct a timeline of Earth's magnetic field history.

How radioactive isotopes are created and used for medical diagnostics

In particle accelerators, protons can be accelerated into other atoms to create radioactive isotopes, which can be attached to specific molecules to create radiotracers that are taken up by specific cells. Radiotracers can emit particles that produce light once they collide with an electron, and this light can be captured by a PET scanner to diagnose specific ailments.

Fluxgate magnetometers detect magnetic fields using electromagnets

Instead of a compass needle's movement indicating a magnetic field, an alternating current produces an oscillating magnetic field in a metal bar. An external magnetic field creates an imbalance in the oscillations, which can be measured quantitatively.

Scientists can create movies of atomic and molecular phenomena using X-ray free-electron lasers, in which images are produced by matter being struck by high-intensity light created by accelerating electrons.

In an X-ray free-electron laser, electromagnetic fields are used to accelerate and move electrons in wiggling patterns, causing them to emit synchronized, high-energy X-rays. This resulting light beam can strike targets up to 120 times per second to create movies of changing molecular structures and phenomena.

Visualize how alternating currents—electricity that periodically changes direction—are generated by rotating magnetic fields, as occurs in turbine-generator systems.

Transformers change the current and voltage across a set of wires by wrapping them around a magnetic core and using the magnetic field of one wire to induce a current in the other.

Can brain scans help with processing trauma?

MRIs and brain monitoring therapies are becoming increasingly popular for those looking to process trauma and address mental health conditions, including PTSD and depression. This article details how these therapies quantify mental health, giving users another way to measure and manage their mental and emotional needs through brain mapping and other methods.

Released in 2024, the polarized image of Sagittarius A* shows that the supermassive black hole at the center of the Milky Way exhibits powerful, spiraling magnetic fields.

Metallic hydrogen exists in Jupiter and Saturn due to high pressure and temperature

This state of hydrogen has metallic properties, including conductivity, which powers these planets' magnetic fields. First theorized in the 1930s, its existence was confirmed through indirect evidence before being created in a Harvard lab in 2017.

Explore human anatomy with these beautiful images

The Human Organ Atlas offers detailed 3D images of dozens of human organs. It was created with very bright X-rays from a particle accelerator, which is formally called a synchroton imaging method.

Watch a histotripsy procedure, a novel noninvasive cancer treatment approach used to destroy tumors with high-intensity sound waves.

Scientists can tag distinct proteins with fluorescent probes that emit different colors, allowing them to visualize multiple biochemical processes simultaneously.

Interacting sound waves can create regions where the pressure from each wave combines, allowing objects to levitate in place against gravity or be manipulated for touch-free construction.

Electricity can flow indefinitely along a ring of superconducting material, which provides zero resistance to the movement of charges due to quantum effects.

Microwave ovens heat food by agitating certain molecules with non-ionizing light

Molecules with resonant frequencies within the microwave range vibrate, producing heat between adjacent matter, just as hands warm when rubbed together. The mesh in front of an oven's door confines the microwaves to the container, while the rotating plate allows different parts of food to travel through regions of maximum vibration.

In Raman spectroscopy, molecules use some of the energy from incoming light to shift into a more energetic vibration and scatter the remaining light, which scientists can use to confirm the molecule's presence.

Listen to the sounds of pulsars, which emit radio pulses up to hundreds of times a second

Just as figure skaters spin faster by tucking in their arms, these celestial objects acquire high rates of spin from the collapse of the cores of massive stars. The star's rotation spins its magnetic field, generating beams of radio waves from its magnetic poles. If either of these poles faces a detector, the signals can be picked up and converted to audio signals.

Solid neon mirrors help trap single electrons to create stable quantum bits

Researchers created this new unit of information for a quantum computer by trapping a single electron near the surface of solid neon. The electron was held in its quantum state by attraction to its mirror image.

Scientists have tested atmospheric models by firing rockets into the aurora borealis

Functioning like components of a CT scan, the missiles transmit signals that can be used to identify charged particles and electromagnetic currents in slices. The slices are then combined to construct a computer-based model of Earth's atmospheric structure, which is used to compare the accuracy of physics-based models.

Neural networks mimic the structure and behavior of real physical systems

Early generative AI systems were inspired by scientific models such as the Ising model, which explains how atoms interact with one another and align in magnets. As these networks have expanded, their behavior has more closely resembled that of quantum fields, enabling them to be used in exploring complex particle physics interactions.

The dynamo theory explains how planets generate their own magnetic fields

According to the theory, a large magnetic field generator, or dynamo, is created when liquid metal flows through the planet's outer core, producing electric currents that generate a magnetic field. Magnetization patterns in rocks on the surface of planets can serve as evidence for the presence of this internal structure at some point in the celestial object's past.

Particle accelerators have been used to reveal detailed ant anatomy

Using a synchrotron facility at the Karlsruhe Institute of Technology in Germany, a pair of X-ray beams swept across about 2,200 ant specimens to create over 200 terabytes of projection images from multiple angles. The images were compiled into micrometer-resolution 3D reconstructions of 792 species, which are freely accessible on the Antscan platform.

View 3D renderings of atomic orbitals created with quantum mechanics

Scientists use the Schrödinger equation to determine how a system governed by a wavefunction—an equation that predicts the probability of certain outcomes—evolves with time. Computers can animate atomic structure and behavior by depicting the wavefunction as a fluid that guides a particle, like water moving a speck of dust.

Glowing chemicals allow scientists to read DNA like a barcode

The process of determining the order of nitrogenous bases in DNA involves first cutting the DNA into fragments, which are duplicated multiple times using bacteria. Fluorescently labeled terminator bases are added to fragments, which are sorted by length and read via laser to reconstruct the sequence.

Physiological changes to the brain on LSD can be captured via MRI

Psychedelics like LSD often take users on novel experiences that can result in lasting shifts in perspective and behavior. See how LSD affects brain activity in this video that details how scientists visually captured the psychedelic's effect for the first time.

Electromagnetic induction creates electricity from a changing magnetic field

The phenomenon was discovered in 1831 by Michael Faraday when an electric current was induced in a wire wrapped around an iron ring after a second wrapped wire not connected to the first was connected or disconnected from a battery.

The magnetic constant sets the strength of magnetic fields

The permeability of free space, or μ₀, contributes to the speed of light in the universe—a fundamental constant. It also helps quantify how the movement of electric charges generates a magnetic field and vice versa.

Scientific applications of bubbles include logic gates, laser production, and medical imaging

Microbubbles of nonreactive gas can be administered to improve the reflection of sound waves and the resulting imaging during an ultrasound. Bouncing light waves within a bubble can stimulate emission of light from a trapped chemical, just as occurs within a laser, and bubbles can act as valves that control the flow and reaction rates in microfluidic systems.

The mass of a cell can be measured using hollow, vibrating beams

In 2010, scientists at MIT constructed a U-shaped device that vibrates like a guitar string with an internal fluid channel. As cells and bacteria pass through the device, its rate of vibration shifts, with greater mass creating larger shifts.

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second.

Neutron star types, categorized by the presence of strong magnetic fields and radiation beams

Magnetars have magnetic fields about 1,000 times stronger than the average neutron star—roughly a trillion times stronger than Earth's. Pulsars emit beams of radiation from their magnetic poles, which appear as flickering radio wave signals as the object spins.

Mixed reality technology helped make repairs to a quantum physics facility in space

In 2021, astronaut Megan McArthur used a HoloLens to work alongside Earth-based engineers and make hardware replacements to the International Space Station's Cold Atom Lab, the first quantum science facility in Earth orbit. The facility cools atoms to near absolute zero to perform quantum chemistry experiments in a microgravity environment.

Wireless charging uses a magnetic field to move charged particles in a battery

Based on the concept of electromagnetic induction, when a compatible device is placed on a charging pad with correct alignment, the alternating current flowing through the pad creates a changing magnetic field. This magnetic field induces a current in the device, recharging the battery without a connecting wire.

How helium greatly improves the efficiency of barcode-scanning lasers

Rather than directly energizing neon atoms, electrical discharge at lower, more practical power levels can excite helium atoms to energy levels nearly equal to those in neon atoms. Within a helium-neon laser, these gases are present in a 10-to-1 ratio, enabling helium to efficiently transfer energy to neon, which is then discharged as red light.