The three smallest bones in the human body—the malleus, incus, and stapes—amplify the vibrations of sound waves by almost 20 times to help enable hearing.

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

This science teacher video systematically walks through the biology of the outer, middle, and inner ear. The explanation starts with the auricle, an external part that funnels sound through the auditory canal, and the tympanic membrane (the ear drum), which vibrates when sounds hit it. Beyond that, as the video details, is the eustachian tube, which is connected to the back of our throats and allows air to pass in and out to equalize ear pressure.

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.

If hearing is damaged, the brain may amplify remaining sounds, perhaps causing tinnitus

Recent mouse brain and ear imaging revealed that the creature compensates for hearing loss by sending signals to the cochlea in the inner ear. This triggers nerve fibers in the inner ear to increase volume and become more sensitive. Learning about these boosted-sensitivity messages from the brain to the cochlea—if they're similar in humans—might help explain tinnitus and fuel experimental approaches to turn down that sensitivity.

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.

A cochlear implant stimulates parts of the cochlea directly, with limited pitch and timbre capabilities

People with these devices have to learn or relearn how to train their brains to interpret nerve signals as sound. The range of the type of sounds that the brain can distinguish with a cochlear implant is limited and consequently it's difficult to understand a tonal language or distinguish individual speakers in a crowd.

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.

View a collection of sound animations, which depict how a source of sound waves pushes against particles to carry energy away without matter being displaced.

Watch how your nervous system's efforts to process silence can contribute to tinnitus

Cochlear cells can be damaged in numerous ways, including aging or exposure to loud noise. If enough cells die, the auditory system can become less sensitive, prompting the brain to compensate by amplifying sound, which is likely to contribute to tinnitus.

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.

In the womb, a fetus may begin to hear at 18 weeks

Though little indentations form on the side of the fetus's neck at roughly nine weeks—with some formations taking place even before then—developmentally, these indentations don't become ears that allow a little one to hear until around 18 weeks.

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.

The bullwhip was the first human-made object to break the sound barrier, producing a small sonic boom heard as a crack when flicked quickly.

The first neural devices were cochlear implants, designed to treat hearing loss

Neural interfaces connect with our nervous system to restore or enhance abilities, such as hearing or movement. These neuroprostheses have enabled the restoration of mobility, communication, and activities of daily living that might otherwise require a caregiver.

Explore a visual and auditory guide to wave properties and waveforms to learn how every sound imaginable can be created by combining multiple vibrations of air.

A sound's pitch will seem to change if the listener or the source moves toward or away from the other because motion changes the time it takes each successive sound wave to reach the listener.

When struck, objects vibrate at unique rates called resonant frequencies, which makes tapping wood sound different from tapping metal, but providing objects with sound at their resonant frequency can cause them to shatter.

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.

Surfer's ear, from repeated cold water exposure, leads to new bony protrusions in the ear

Frequent exposure to icy cold water, typical in surfing, can cause tiny bony growths to develop in the ear canal, informally called surfer's ear. While the exact cause for these growths is unknown, it may be the body's protective response to shield the ear drum from the cold. These protrusions can heighten the risk of swimmer's ear, lead to wax buildup, and result in hearing loss.

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.

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.

Stonehenge may have functioned as an echo chamber designed to keep ceremonies secret from outsiders.

Acoustics researcher Trevor Cox discovered that Stonehenge acts like a concert hall, reflecting and amplifying sound. This video shows Cox demonstrating the effect using a scale model inside a soundproof studio.

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.

BPPV occurs when tiny calcium particles called otoconia become dislodged

WIth this condition, formally known as benign paroxysmal positional vertigo, calcium particles that normally help the brain interpret head movement and position migrate for unknown reasons into the ear's semicircular canals, sending irregular nerve impulses to the brain, which cause intense vertigo episodes.

Cochlear implants are raising questions about deaf identity and culture

The rise of cochlear implants, which are usually covered by insurance and can enable hearing for many patients, raises questions about what it means to be deaf, the effects on deaf individuals learning American Sign Language, and about deaf culture. Watch this video that discusses the controversies and spotlights a little girl who hears for the first time with her cochlear implant.

Some animals may speak because of duplicated connections in the brain

Neuroscience suggests that connections responsible for motion made during embryonic brain development—such as those connecting hearing and movement pathways that allow reactive motion when started—are duplicated and connected to the larynx in some animals. This allows some mammals and song-learning birds to speak, provided they have the necessary physiological structures.

Listen to samples of 'sounds' produced in the sun's interior, created from the sonification of internal vibrations detected by the Parker Solar Probe.

Nasal hairs, called vibrissae, help protect the body from particulate matter and other dirt

The nose structure plays a key role in filtering air before it enters our lungs and makes sure that the air temperature and humidity are also suitable for the body.

We may be using Q-tips in our ears—even when we shouldn't—because they can stimulate pleasure nerves

People continue to use Q-tips inside their ears even though we know it's risky. Some clinicians suggest that beyond the desire to get water out, this may be because the nerve bundle called the vagus nerve, which spans from the brain to the large intestine, can be stimulated that way, causing a pleasurable sensation in other body parts including the heart, belly, or genitals.

Within an anechoic chamber, all surfaces are covered with specialized materials that prevent wave reflection, helping prevent sound from echoing in the space.