Most advanced touch screens rely on electrical charge in your skin

The most common types of touchscreens are capacitive and resistive

Capacitative screens are coated with a conductive material that creates a uniform electric field, which is disrupted by fingers. This disruption is registered by the device across a grid to determine where contact was made. Resistive screens identify touch when fingers push gap-separated sheets into contact with one another.

How do touchscreens work?

Touchscreens have revolutionized digital interactions, but how they work widely varies depending on the device. Explore the history and workings of the most common types—capacitive and resistive—and new interaction methods incorporated into foldable screens and touchless interfaces.

Efforts to build touch-enabled machines highlight the complexity of human touch

The challenges that engineers are facing as they try to reproduce a human's ability to touch and also give robots the ability to interpret that kind of sensory flow are furthering our understanding of the myriad intricacies of human touch—and the challenges in emulating it.

You have never made physical contact with anything in your life because electrons in the outer layer of atoms on the surface of objects repel one another.

Simulate the buildup and discharge of static electricity through friction by dragging the arm and leg of 'John Travoltage' along surfaces.

How brain cells carry information

At any moment, there is an electrical storm coursing through your body. Discover how chemical reactions create an electric current that drives our responses to everything from hot pans to a mother’s caress.

We can sense touch even through a tool

Research published in 2019 indicates that the same brain regions involved in sensing touch on the body also process it when humans use a tool to do the touching. Essentially, it's acting as a sensory extension of the body. (Some users may experience a paywall.)

Brain-reading devices are helping paralyzed people to touch

In clinical trials, implanted brain-computer interfaces are allowing dozens of individuals with paralysis to control prosthetics that are restoring a range of skills, including drinking coffee and feeding oneself. One area of related prosthetic research is creating a synthetic sense of touch—coupling the brain implant with pressure sensors in prosthetic robotic fingertips to enable an approximation of a sense of touch.

Humans likely cannot tickle themselves because there's no element of surprise

Unraveling the neural mechanisms of tickling—formally called gargalesis—is an area of active research, but a leading theory about why we can't tickle ourselves is that the brain's somatosensory cortex processes self-touch differently than it does external touch. The cerebellum already anticipated what was going to happen when you move your hand for self-touch, limiting the effectiveness of a self-tickle.

In the photovoltaic effect, light generates electricity by creating a charge imbalance after knocking electrons out of atoms in the semiconducting materials of solar cells.

Explore how excitatory cells, such as neurons and muscle cells, transmit information in the body via electrochemical signals, which can travel up to 120 meters (390 feet) per second.

Electrogenic animals generate their own electricity within an electric organ by changing the pattern of electrical charges in disc-shaped cells called electrocytes.

Touch is the first sense a fetus develops in the womb

During gestation, our sense of touch begins to develop around 8 weeks, starting with the development of sensory receptors in the face and, about a month later, in the palms and soles of the feet.

Flexible integrated circuits can be built from carbon nanotubes and elastic materials

Stanford researchers arranged the nanotubes in fishnet-like networks that allow deformation without loss of function. The stretchable ICs have been shown to power micro-LED displays and may be used in smart clothing.

When humans perceive touch, the information is sent to the thalamus and then to the primary somatosensory cortex, the part of the brain that receives sensory input.

Tattoos, explained

Tattoos last because immune cells trap ink beneath the skin—but there's more to the story. This overview looks at how ancient cultures used tattoos for status, spirituality and punishment; how technology like the electric tattoo machine transformed the art form, and where innovations like smart tattoos could take it next.

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.

A smartphone contains over a dozen rare earth elements

One of the most important elements is indium, which makes up an electrically-conductive mesh beneath the display that provides touchscreen functionality. Alloys containing REEs are used in the magnets needed for the microphone and speaker.

Water vapor is used to manage heat in high-end smartphones

While smartphones have traditionally been cooled using a highly conductive plate that dissipates heat from the chip, vapor chambers offer a higher heat-removal capacity. This technology has been utilized in laptops for decades to absorb heat by cycling a fluid between liquid and gaseous phases.

Electricity can be lethal because it can disrupt the nervous system, which controls critical bodily functions that rely on electrical signals between cells, such as breathing and heart rate.

Mind-controlled bionic arms use nerve implants to restore sensation and movement

Unlike traditional prosthetics that rely on surface electrodes or mechanical parts, this system uses implanted titanium and nerve-connected electrodes to enable a seamless brain-to-arm connection. Patients train in virtual reality with their implanted signals before using the physical prosthesis.

A web of sensory neurons in the skin help filter out background sensations

The somatosensory system helps us organize and navigate our surroundings, enabling us to understand our bodies in relation to our environment and also filter out minor sensations that are basically background noise so they aren't overwhelming to our bodies. Meanwhile, viscerosensation—or internal sensation—refers to the internal sensory neuron system that conveys information from internal organs to the brain.

Touch deprivation can heighten anxiety and depression

Pacinian Corpuscles are pressure receptors just under the skin that send signals to the vagus nerve in the brain—that's the cranial nerve which regulates involuntary actions like breathing, heart rate, and the general "fight or flight" response. Activating those receptors can slow the heart, decrease blood pressure, and lead to the release of oxytocin and cortisol. The absence of touch, conversely, can promote negative feelings.

A Venus flytrap's hairs convert sensory touch into electrical signals

A stretch-activated ion channel called DmMSL10 acts as an amplifier, converting grazing contact into a strong impulse that the plant uses to react and close its jaw. To distinguish prey from raindrops or other stimuli, the jaw only closes when the hairs are touched twice in quick succession.

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

A simple explanation of semiconductors

Semiconductor chips are electronic devices that store and process information. Today they can contain billions of microscopic switches on a chip smaller than a fingernail. The article provides a quick overview of how the devices work and how they've provided the backbone of the computer age.

Parents and romantic partners naturally touch at speeds optimizing nerve activation

A small observational research study shows that when parents are asked to caress their infants and volunteers are asked to caress their partners, both groups spontaneously stroke their loved ones at velocities that, on average, fell within the optimal range to stimulate the C-tactile afferent nerve receptors. This wasn't the case when volunteers were asked to do the same with an artificial arm, which they stroked much faster.

Electricity is produced when the ends of a battery are connected by a conducting wire, triggering chemical reactions that release the energy stored in chemical bonds.

Mixed reality devices and other wearables may usurp smartphones

The integration of smartphone features into watches, glasses, and even clothing suggests future technology may be geared toward working independently in the background. Mixed reality technologies are expected to facilitate this ambient computing world by seamlessly and proactively displaying real-time content without physical interactions solely in the real world.

On average, the human body produces about 100 watts of electricity—enough to power a light bulb—but some people can produce over 2,000 watts in short bursts, such as when sprinting.

Artificial goose bumps could theoretically be used for information storage

Inspired by how fine hairs stand on the skin with goose bumps, researchers have recently created artificial skin that raises artificial goose bumps when exposed to a laser. This type of precise, localized, and controllable system could potentially fuel later development of programmable machines that could be used for information storage.

Lightning rods provide a conductive pathway to safely steer massive electric currents

The device is positioned higher above the ground to "catch" one of the many branching filaments of electrons from clouds before they make contact with other surface structures, which have been induced to have a positive charge by overhead storm clouds. The current is then sent to a conductive grid buried underground.

Simulations suggest ice's slipperiness comes from rearranging molecules

Past models have proposed that slipperiness arises from a thin layer of liquid water formed at the ice's surface by frictional melting. However, new research suggests that electromagnetic forces between interacting surfaces push water molecules out of an ordered, crystalline structure and into a shapeless, soft, slippery layer. This process occurs solely through contact, independent of pressure or friction.

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

Dust particles on Mars can generate lightning

Through triboelectric charging, sand and dust on the Martian surface can become electrified when they rub against one another, causing friction to displace electrons and create charged particles. If this matter forms a strong enough electric field, it can overcome atmospheric insulation and produce electrical discharges, resembling lightning on Earth.

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.

Semiconductor chips are electronic devices that store and process information

They can contain billions of microscopic switches on a chip smaller than a fingernail. An article provides a quick overview of how the devices work and how they’ve provided the backbone of the computer age.

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.

Brain-computer interfaces create a direct link between the brain and external devices

The technology enables users to control prosthetics, computers, or even games using only their thoughts. In 2021, a monkey played table tennis using only its brain, thanks to a Neuralink device, marking a major milestone before human trials began in 2024.

SpaceX's Crew Dragon was the first crewed spacecraft piloted by touchscreen

In May 2020, NASA astronauts flying SpaceX's Crew Dragon to the International Space Station used touchscreen controls instead of traditional switches and dials, a significant shift for astronauts and how they pilot and interact with spacecraft. (Some users may experience a paywall.)

Disney Research developed a haptic interface where you can feel a fireworks display

Disney’s “Feeling Fireworks” uses water jets and a latex screen to replicate fireworks for blind individuals. Such technology may also provide inclusive experiences for the deaf community, though as of 2024, there are no plans to implement them in Disney parks.

Blindfolded people could identify objects by touch alone a week after encountering them

These touch memories are more complex and durable than previously thought. In research published in 2018, blindfolded volunteers touched over 150 household objects for about 10 seconds each, and afterward correctly identified the objects more than 90 percent of the time when presented with the object and a similar one. Participants still knew most of the objects a week later with about 85 percent accuracy. (Some users may experience a paywall.)

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.

On credit and debit cards, magnetic stripes have been slowly replaced by microchips that use dynamic, encrypted data to prevent card cloning and counterfeit fraud.

Shorter, more frequent touches are better than longer, rarer ones

That's according to a 2024 meta-analysis of 137 studies on touch. It found that as long as the touch is consensual, the identity of the toucher mattered little for adults, and there was even a benefit to receiving "touch" from objects like weighted blankets or robots. For newborns, however, the identity of the toucher did matter, and the greatest benefit came from parental touch.

The gradual loss of capacity in rechargeable batteries can be delayed by avoiding overnight charging, charging to 100%, fast charging, and exposing your device to excessive heat.

Lightning forms when streams of rising and falling charged particles connect

In cloud-to-ground lightning, a buildup of negative charge at the bottom of clouds repels electrons on Earth's surface, leaving behind positively charged particles. When descending negatively charged air—the stepped leader—meets rising positively charged particles—the upward streamer—brightening runs up the connection, producing intense flashes known as return strokes.

Microchips in payment cards improve security by generating unique transaction codes

Magnetic strips store unchanging data that is easily cloned, but microchips act as miniature computers that encrypt sensitive data. They also resist fraud by creating data unique to each transaction, preventing duplication.

Watch lightning strike a building at 40,000 frames per second

When the built-up layer of negative charge at the bottom of clouds is sufficiently high, a network of charge filaments will emerge. If one of the filaments meets a rising strand of positively charged particles, a highly conductive path forms, and charges across all filaments move to the path, generating lightning

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.