We hear because soundwaves are converted into electrochemical signals in our ears

Cochlear implants stimulate nerves inside the ear to provide the sensation of sound

In a surgical procedure, one part of the implant is placed under the skin behind the ear and electrodes are threaded into the cochlea in the inner ear. Another part of the implant sits behind the ear and picks up sound and then converts it into patterns of nerve stimulation.

See what loud noises do to inner ear hair cells

This animation illustrates how louder music can affect inner ear hair cells. Damage to these cells is generally considered permanent. Hearing protection like ear plugs can reduce the level of sound entering into the ear and help protect those cells.

Age-related hearing loss, known as presbycusis, is a top cause of hearing loss

This video walks through the biology of why presbycusis (prez-buh-kyoo-sis) occurs and its etiology. This type of hearing loss is gradual and typically starts with reductions in the ability to hear high-pitched sounds.

Learn about swimmer's ear, which sickens 1 in 10 Americans

This outer ear infection—in the tube leading from the ear opening to the eardrum—is usually caused by bacteria. Formally called otitis externa, this condition is commonly called swimmer's ear because microbes can enter the ear canal while swimming.

The inner life of a cell

White blood cells are responsible for protecting the human body from infection. This video uses biophysical data from Harvard researchers to accurately demonstrate what goes on inside one white blood cell as it works within the immune system.

Listen to samples of 'sounds' produced by the sun's internal vibrations

Sonification can turn otherwise inaudible vibrations into audible sounds, just as scientists colorize images of celestial objects taken outside the visible range into colors our eyes can interpret. This has been used to turn the vibrations within the sun detected by the Parker Solar Probe into audio clips that resemble chirping and whistling.

The anechoic chamber at Bell Labs absorbs 99.999% of created sound

The space nearly eliminates sound wave reflection, allowing visitors to become aware of noises created by their own bodies, including their heartbeat and skeletal conduction. Experiments inside have contributed to the development of digital audio and phone touch tones.

Some animals possess sensitive hearing to help pinpoint prey and map the world

Bats and dolphins produce sound to reflect off surfaces and create a mental image of their surroundings. Owls' faces are dish-shaped to help funnel sounds to their ears, including that of mice moving along leaves or snow. Pinnipeds, such as seals and walruses, hear in both air and water.

How the five senses share information with each other

The human body depends on information from the five sensory organs—the eyes, ears, nose, tongue, and skin—to react to the world around it. Each of these organs, in its own way, relies on complex circuitry to send signals back to the central nervous system.

Engineer explains VR at five levels of complexity

While its possible to grab a virtual reality headset and hop into an immersive world with little effort, a significant amount of technical and biological science has gone into creating the effect of a 3D world. This video breaks down the technology in five layers of increasing complexity.

Take a journey to the Earth's core

This animated video takes you on a journey through the different layers of the Earth's core, with insight into what makes up each shell. Earth's outer core, which is about 1,400 miles thick, is made up of liquid iron and nickel at a blistering...

Hear examples of what tinnitus can sound like to those suffering from it

This video, from a Scottish branch of the UK National Health Service, features different types of ringing, crackling, and other sounds that tinnitus sufferers experience. Individual responses to such phantom sounds may vary widely.

Neurons send signals through electrical impulses and chemical messengers

By converting electrical signals into chemical messages at synapses, neurons allow information to travel throughout the nervous system. With repeated use, synapses grow stronger, enhancing the associations between neurons.

What a tiny marine worm can tell us about our brains

Meet the amphioxus, a small eel-like animal that has a lot to teach us about brain evolution. The genetic roots of our brains can be seen in these unusual creatures. This three-minute educational video focuses on the evolutionary history of the human brain through these odd little critters with a 500-million-year-old history.

How the body produces urine

Things seem so simple when nature calls. But, how does the body actually produce the urine we so regularly and thoughtlessly expel? This detailed, comprehensive animation walks viewers through every step with precise illustrations, from the kidney's filters (known as nephrons) to the direct nerve connecting the bladder to the brain. See how the body does it here.

Learn about the basic anatomy of mosquitoes

This short explainer video breaks down the mosquito's general body components, highlighting how mosquitoes breathe, fly, and more. It also touches on how experts can tell different mosquito species apart.

The physics behind opera singing

How can opera singers project their voices to audiences in huge auditoriums without using microphones and overpowering the orchestra? This video explains this phenomenon, using animation to demonstrate the physics of the human voice and how opera singers hone their technique to hit higher frequencies and a distinctive ringing timbre known as their squillo.

Peripheral vertigo is a type of dizziness caused by disturbances the inner ear

This type of vertigo can be triggered by several factors including viruses that cause inflammation in the inner ear, Ménière's disease, or benign paroxysmal positional vertigo, which can cause irregular nerve impulses that cause dizziness.

Learn how your body is, scientifically, like a firework with its own slow, controlled burn.

How radio works

Antennae tune a radio to a particular frequency (determined by the listener on their radio's dial) while tuning out all the other stations being broadcast. AM, short for amplitude modulation, and FM, short for frequency modulation, decode audio signals differently, leading to differences in sound quality and the distance a station can travel.

Why we have different seasons

Visualize just how exactly seasons come to be with this animation of the earth in relation to the sun, and see how earth's tilt determines our seasons.

The sound of thunder can vary based on your distance from lightning

The rapid flow of electricity heats and pressurizes air, causing it to expand and produce a shockwave at each point along the bolt at multiple frequencies. As these shockwaves overlap, higher-frequency sounds, which produce a sudden crack, dissipate more quickly, while lower-frequency sounds—long booms and rumbles—travel farther.

Why parrots can talk like humans

Birds are built with incredibly versatile tracheas that can mimic all kinds of sounds from their environment. For parrots, that includes human speech. This brief video explains why birds, who have such distinct anatomies from humans, are somehow able to talk like them, anyway.

Explaining how water's movement between different salt concentrations can generate electricity

Water naturally moves from regions of low salinity, such as freshwater, to regions of high salinity, such as ocean water, across a semipermeable membrane. This movement produces pressure that can be harnessed in osmotic power systems to drive turbines and generate electricity, much like in hydroelectric plants.

View the electromagnetic spectrum and the properties of different types of light

All forms of electromagnetic radiation, from radio waves to gamma rays, travel at the speed of light in a vacuum, but their wavelengths decrease as their frequencies increase. The light-sensitive nerve cells in the human eye are sensitive to a narrow range of values, which we observe as the spectrum of visible light.

Wave-particle duality—a simple overview

Our notion of reality is built on everyday experiences. But wave-particle duality is so strange that we are forced to re-examine our common conceptions. Wave-particle duality refers to the fundamental…

Fish populations in the Great Barrier Reef have increased after installing waterproof speakers on the ocean floor that played recordings of sounds from healthy coral reefs.

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

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.

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.

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.

A pickleball's loud 'pop' sound can reach 120 decibels, which is equivalent to a hammer hitting a nail

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

The boiling temperature of water decreases with increasing elevation because the molecules need less energy to overcome the lower atmospheric pressure associated with thinner air.

Hear 50 years of iconic hip-hop samples, the genre's foundational looped tracks

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

Bone marrow (soft tissue found inside certain bones) generates roughly 500 billion new blood cells each day

Explore chaos in this simulation of two double pendulums, where small differences in the release angles produce wildly different outcomes.

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

Explore what it's like inside a patient isolation unit, used in situations such as treating a patient or suspected patient with Ebola.

Learn how to read a prospectus, the juicy document that any company must file with the SEC before going public.

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.

The animatronic shark from Steven Spielberg's 'Jaws,' the first modern blockbuster, was a complex underwater apparatus called 'Bruce.'

Children are now three times more likely to say they want to be a YouTuber when they grow up than an astronaut, with some even attending 'YouTube camps' that teach kids how to create content for the platform.

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.

Clever Hans was a 1900s horse that was believed to be able to solve math equations, tell time, and read and comprehend German, until a psychology student discovered how he got his answers.

Play the role of a student in a game where you try to navigate college and remain debt-free, selecting different income levels, high school experience, race, ethnicity, and more.

SpongeBob exemplifies Aristotle's philosophy for living well because he understands that happiness doesn't come from external factors like money, recognition, or power.

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by over 1.5 million Muslims.