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

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.

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.

Fast charging can lead to battery degradation if the device does not stay cool

Modern phones use software to monitor charging habits and can activate adaptive charging to delay charging rates and prevent overheating. When charging, devices should not be confined (e.g., stored in your pocket) or placed in direct sunlight, as this can trigger heat warnings and sudden shutdowns.

Contactless credit cards descend from a batteryless Cold War listening device

The same physics that let Soviet spies eavesdrop on the US ambassador in 1945 underlie contactless payment methods today. The device is a passive chip powered wirelessly by incoming radio waves.

Most advanced touch screens rely on electrical charge in your skin

Capacitive touch screens store electrical charges in an electrostatic grid of tiny wires. When we touch the screen a tiny electrical charge is transferred from the screen to the finger to complete a circuit (since skin has positive and negative charges). This connection creates a voltage drop on that point of the screen. Cloth, however, doesn't conduct electricity, which is why humans can't wear thick gloves and operate their smartphones.

Faraday cages protect enclosed objects by redirecting electrical currents

Constructed from conductive materials, the cage allows electrons to distribute themselves evenly throughout its surface and travel to ground, keeping the interior neutrally charged and preventing any internal electricity. The same principle blocks electromagnetic waves by redirecting the electric field component, preventing telecommunication signals from entering the apparatus.

Light energy can be transformed into electricity in solar cells via the photovoltaic effect

When light strikes semiconducting material, it can knock electrons out of atoms, creating a charge imbalance within the material. A wire connecting the oppositely charged regions can allow electrons to flow back, balancing the charges and producing an electric current that can be harnessed to power devices.

Boost your Wi-Fi with aluminum foil

A surprising hack using aluminum foil can potentially improve Wi-Fi signals, to many readers' surprise. Check out the science with this brief article. Wi-Fi signals spread like radio or light waves from a router's antenna, often leading to...

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.

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.

How cosmic rays and pointed ice shards help generate lightning in clouds

Although clouds generate electric fields as electrons are transferred when currents move past one another—not unlike building up static electricity by rubbing socks against carpet—these fields have been measured to be a tenth of the strength needed to make electricity strong enough to travel through air. However, pointed crystals are estimated to boost fields by factors greater than 10, and particles from outer space may help initiate cascades of displaced electrons.

Nikola Tesla’s biggest dream was a worldwide network of wireless power transmission

He built the Wardenclyffe lab and a massive prototype transmission tower to develop trans-Atlantic transmission, but it was never operational. The concept was based on incorrect assumptions about Earth's conductivity, but it inspired subsequent efforts for wireless systems.

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.

Elon Musk's Neuralink's N1 chip can wirelessly read brain signals from over 2,000 electrodes

The device is a battery-powered brain implant that transmits data via Bluetooth. Neuralink's near-term objectives for the device focus on unlocking new treatments for paralysis, neurological disorders, and some psychiatric conditions.

Pure water does not conduct electricity because this flow of energy requires the movement of charged particles, and water is a neutral molecule.

More batteries in the power grid would create an on-demand energy reservoir

Most power grids are inefficient because they require enough generation capacity at all times to avoid blackouts. This means at any given time, as much as 50% of generating capacity at power plants can go unused. Batteries would reduce this inefficiency and allow for real-time adjustments.

Genetically modified viruses can help construct battery electrodes

MIT scientists' modifications caused the viruses to attract conductive materials, such as gold ions, which the viruses self-assembled into nanowires that could be used in batteries. These components allow batteries to be thinner and flexible enough to be constructed into new shapes.

The Higgs boson provides a mechanism that explains why some particles have mass

The mathematics of quantum field theory suggested that force particles should be massless, like the photon for electromagnetism, but the weak nuclear force’s equivalent W and Z particles are not. The Higgs field provides mass when interacting with such particles.

A battery management system determines the displayed battery percentage

The software in modern devices provides values by combining estimates based on voltage—akin to knowing how much air is left in a tire based on the pressure of the escaping air—and coulomb counting, where the rate of electrical current is calibrated to the ratio of remaining charge to full capacity.

Battery and plug-in hybrid EVs can operate with zero tailpipe emissions

Battery electric vehicles only run on electricity, while plug-in hybrids incorporate a small internal combustion engine that recharges the battery or directly powers the wheels to improve driving range. Fuel cell electric vehicles convert hydrogen gas fuel into electricity.

Laser-etched electric charges guide toner during laser printing

When sending a print job, the file data generates an image that a laser maps positively charged regions onto a drum separately for each color toner. Once the negatively charged toner is applied where it was electrically attracted, heat and pressure fuse it onto the paper.

How do 5G base stations work?

5G relies on a combination of base stations, including macrocells, small cells, and femtocells. The differences between the three are apparent in size, coverage, and cost—but, small cells in particular are key to providing the high millimeter wave frequencies 5G promises. Learn more in this three-minute video.

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.

Photonic integrated circuits use light instead of electrons within circuit components

Instead of processing electric signals, photons in the visible and near-infrared serve as optical signals between chips made of electro-optical crystals. PICs can enable lower power consumption and heat generation by eliminating the friction from electrons moving along wires.

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.

Windmills can be designed to pump groundwater for irrigation or land drainage

A gearbox within the windmill converts the windmill's rotation into the vertical motion of a piston that pushes water up a pipe. It also drives the rotation of an Archimedes screw to move water to higher elevations.

Planeterrellas create artificial auroras that mimic the atmospheric displays of light by setting up an electric field between two metal balls in a jar filled with a small amount of air.

Electrical grids worldwide must double their power delivery capacity by 2050 to meet surging demand from AI and electric vehicles.

Radioactive elements can introduce software errors because the ionizing radiation they produce can detach electrons from atoms, and computer code relies on the distribution of electrons.

The history of many kitchen appliances involves unexpected discoveries and applications, including wartime radar turned hamster defroster and replacing an 'ice king' with heat-stealing boxes.

Sony set the standard for cylinder-shaped batteries when it repurposed manufacturing equipment used to make rolls of magnetic recording tape.

How fusion—which releases energy when two lighter atoms combine to form a heavier atom—differs from fission

How Amazon operates a 'flywheel' business model, a self-reinforcing cycle that drives continuous growth

The use of fungi to detoxify land and water—a process known as mycoremediation—has been used to clean up natural resources affected by the 2025 California wildfires.

Hedge funds, the private investment firms that trade a wide swath of financial assets, make money by imposing steep fees on investors and from the fund's investment performance.

Memecoins are a type of cryptocurrency—a form of digital currency with a wide variety of uses—created around popular 'memes,' or viral internet jokes.

Tattoos remain visible on your skin thanks to immune cells called macrophages

Some researchers have labeled nomophobia, the fear of being without your phone, as 'the phobia of the 21st century.'

Hurricanes, which rely on air consistently spinning in the same direction, cannot cross the equator because air curves in opposite directions north and south of it.

After 25 people used virtual reality headsets to practice flying with virtual wings—flapping their arms—their visual cortex responded to the wings almost as if they were real arms, treating them as body parts.

According to the physics of black holes, our 4D reality may be a hologram—a projection of information coded on a 2D surface on the edge of the universe.

Long before Major League Baseball began allowing instant replay for balls and strikes, an umpire reluctantly used the technology to determine whether a hit was a home run, a move that inadvertently ushered in a new era for the sport.

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

Listen to an in-depth conversation on the links between Parkinson's disease and herbicide exposure and the challenging pace of scientific investigation.

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.

'Silent' fireworks have gained more interest in recent years as a quieter celebratory option.

To reduce wrinkles in clothing, research recommends gentle wash cycles with more water and tumble drying with smaller loads and longer times.

Ebola is a filovirus, meaning it resembles a thread under a microscope, though it sometimes twists and can resemble a bowl of spaghetti.

Use this tool to calculate the dollar value of your parental mental load, from meal planning to coordinating after-school care, then see resources that help generate solutions.