The decibel scale measures sound intensity, with hearing damage occurring after prolonged exposure to sounds above 85 decibels—equivalent to a noisy lawnmower.

See this graphic describing what different decibel levels mean for hearing loss.

More than 5% of the world's population has disabling hearing loss

Disabling hearing loss is defined as hearing loss greater than 35 decibels in the better hearing ear. (For context, that means the sound of leaves rustling, at roughly 30 decibels, would be inaudible even to your better-hearing ear.) The World Health Organization's data suggests that more than 5% of the world's population has this level of loss requiring rehabilitation, which amounts to 430 million people—including 34 million children.

One decibel of hearing loss increases tinnitus risk by 6% for older people

That's according to an analysis of more than 18,000 people published in BMC Medicine in 2023. The tinnitus risk is not just limited to older people: The research also concluded that one decibel of hearing loss increases the risk of developing tinnitus among young adults by 3 percent.

Mapping hearing loss in the US

Nearly 10% of Americans suffer from some degree of hearing loss, measured as the inability to hear sounds lower than 25 decibels. The incidence of hearing loss increases with age and is typically higher among men. Recent analysis produced a puzzling observation researchers can't quite explain: There's a larger incidence of hearing loss among rural populations than in urban centers. Explore the data with this map and explainer.

Pickleballs' loud 'pop' sound can reach 120 decibels, equivalent to the sound of a hammer striking a nail.

'Silent' fireworks are not entirely noise-free

By using a reduced amount of flash powder—the ingredient responsible for the loud explosions that fireworks make—"silent" fireworks produce displays between 70 and 90 decibels, rather than the approximately 175 decibels heard in professional displays.

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.

Hearing loss can affect balance and make falls more likely

For reasons that are not yet fully understood, hearing loss seems to increase the risk of falls. One explanation is that reduced environmental awareness due to hearing loss may put people at greater risk. Another theory is that the brain has to work harder to process sound with hearing loss and that cognitive load may also boost the chances of falls. One study found that for every 10 decibel increase in hearing loss, there was a 1.4 fold increased odds of falling in the preceding 12 months.

See worldwide hearing loss by age group and country

This 2023 data from the Institute for Health Metrics and Evaluation shows the estimated number of people with complete hearing loss in different age groups per 100,000 people in the population. Individuals aged 70 or older make up the largest group with this type of hearing deficit.

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

Objects that move faster than the speed of sound—Mach 1—create shockwaves called sonic booms by building up and forcing sound waves to combine as they lag behind the object.

A magnitude 25 earthquake would release enough energy to destroy the sun, while a particle of dust drifting onto a table would have a magnitude of about -15.

Arnold Schoenberg expanded the confines of music by abandoning traditional chords and embracing dissonance.

Try out an online tone generator, which produces sounds of specific frequencies to help tune instruments, test your hearing, and generate beats by overlapping tones.

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.

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.

People with tinnitus should avoid silence—sound-rich environments distract the brain

This podcast from an audiologist discusses common questions about tinnitus. It notes that tinnitus could be described as a phantom sound associated with hyperactivity in the brain. It's linked with loud sound exposures above 85 decibels, hearing loss associated with aging and stress, among other factors.

The Grateful Dead pioneered a massive 3-story, 75-ton, 600-speaker sound system that revolutionized live audio in the early 1970s.

Visualize the power and frequency of earthquakes across the moment magnitude scale, where a whole number increase corresponds to about 32 times more energy released.

Tinnitus estimates vary, but may occur in 10%-15% of the population

This video discusses the mechanisms underlying tinnitus and explores the knowns and unknowns about the condition. Tinnitus most commonly occurs among those with hearing loss, suggesting that cochlear damage may be a factor.

Hearing loss is linked with brain volume reductions

The brain looks different as a result of hearing loss, with reductions in brain volume overall and in specific areas, and these changes are hypothesized to impact cognition. Exactly why hearing loss alters cognition is an active area of research, but theories include that the elevated cognitive load of straining to hear affects brain power available for thinking and memory and that hearing loss leads to social isolation which boosts dementia risk.

Because the Richter scale was calibrated to crustal and mantle properties in Southern California, seismologists have instead used the moment magnitude scale to quantify earthquakes since the 1970s.

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.

Thunder occurs when fast-flowing electricity heats and pressurizes air, causing it to expand and produce a shockwave at each point along the bolt at multiple frequencies.

In television and film, certain sounds, such as dialogue, may be difficult to understand due to sound mixing, device limitations, and technological advancements that have collectively reduced clarity.

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 common sounds become disturbing

Misophonia causes certain sounds to feel violating, triggering a "very visceral kind of experience" filled with extremely unpleasant emotions, including annoyance, anger, and disgust. A 2017 study found that people with misophonia have elevated activity in the brain's anterior insula—a region associated with interoception, emotional processing, and behavioral responses—when exposed to trigger sounds. Ongoing research suggests trigger sound context affects the severity and manifestation of the condition.

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

How 'vibes' factor into scientists' decisions about using certain units

Although there are absolute quantities from which units can be defined, such as the speed of light and the corresponding light year for distance, the usefulness of units comes from their ability to easily communicate values, rather than how fundamental their origins are. For example, while Kelvin measures absolute temperature, Celsius is scaled to the temperatures of boiling and freezing water, making them more practical for everyday usage.

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 Stonehenge sounded like

Researchers built the first scale model of the world's best-known prehistoric stone circle, Stonehenge, to study its acoustic properties. Built approximately 5,000 years ago, the landmark in southern England has puzzled historians for centuries, but...

Audism is institutionalized discrimination against deaf people

Promoting the idea of hearing-at-all-costs in medical and education settings has created division in the deaf community and influenced decisions about learning sign language.

Tornadoes produce inaudible signals to humans hours before forming

Researchers at the National Oceanic and Atmospheric Administration have found that tornado-producing storms generate specific sounds below the range of human hearing, much like the infrasonic signals produced by earthquakes and avalanches. Although difficult to distinguish from wind noise, scientists hope to build systems that use these signals to improve tornado forecasting.

Data suggests the typical horse produces over 12 horsepower—a unit of measurement for the rate of work done that was conceived as a marketing tool to communicate steam engine performance.

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.

How hearing protection became cool

In recent years, the WHO shared research findings that over 1 billion teens and young people face risks of hearing loss due to unsafe listening practices. While earplugs used to hold a reputation for being uncool, this article explores how awareness has led to more people fashioning different types of hearing protection. Explore the growing trend of earplugs at raves, concerts, and other loud events.

Beethoven's correspondence in 1801 documented his tinnitus suffering

Ludwig van Beethoven's hearing loss is one of the best-known cases of this condition among historical artists. He also suffered from tinnitus and wrote in 1801, "My ears are buzzing and ringing perpetually, day and night. I can with truth say that my life is very wretched…"

More than 90% of American deaf children are born to hearing parents

The National Institute on Deafness and Other Communication Disorders have collated top statistics about hearing loss in the US including differences by age, racial groups, and other factors.

Since 1983, the meter has been defined based on the speed of light

The 1875 Metre Convention established the unit as the length between two lines inscribed on the surface of bars made by the International Bureau of Weights and Measures. Advancements in the measurement of light redefined it as the distance light travels in 1/299,792,458 of a second.

China reports the highest prevalence of hearing loss and South Africa reports the lowest

This conclusion comes from research published in 2025 that analyzed self-reported hearing loss and hearing aid use from long-term studies that covered 28 countries. Its findings included that the countries with the greatest prevalence of hearing loss (China, South Korea, Mexico, and Brazil) also had the lowest levels of hearing aid use.

An ear doctor with hearing loss seeks to help those with hearing loss enjoy music

Alex Chern, an ear doctor who has hearing loss himself, dreams of restoring the ability to experience "all the richness and the beauty of the sound of music" for patients—not just functional hearing. Hearing aids amplify sound waves and aren't designed to work well with music that may have varied pitch and volume. Chern is studying how hearing loss and engaging with music may affect cognitive decline.

Cooling each square foot of a room requires at least 20 BTUs of capacity

British thermal units describe the cooling capacity of air conditioners, though noise levels, directional airflow, and filtration also affect their effectiveness. Insufficient BTUs are unlikely to cool a large enough room faster than the environment warms the air.

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.

If a source of music traveled past someone at twice the speed of sound, assuming sufficiently sensitive hearing and powerful equipment, they would hear the music backward.

Sonar, or sound navigation and ranging, uses reflected sound waves to map and detect seafloor features, marine organisms, and other obstacles.

Noise from data centers may disrupt wildlife and local residents

Individuals living where local ordinances have allowed data centers to be built next to residential areas have reported that the constant humming and vibrations from cooling systems have prevented them from sleeping and exposed them to chronic noise, which the American Public Health Association says can lead to cardiovascular disease and increased stress.

Misophonia is a neurological disorder where sounds trigger strong emotions

The phenomenon is characterized by decreased tolerance to specific sounds, such as heavy breathing, pen clicking, and water dripping, which trigger a fight-or-flight response. The resulting emotions, which can range from irritation and disgust to anxiety and fear, can be overwhelming and uncontrollable.

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.

Notch music therapy may filter out some tinnitus frequencies

Researchers in Germany have developed a smartphone app-based therapy for individuals with tinnitus associated with hearing loss. Some people with tinnitus can use this Notch app with their hearing aids to at least partially block sound frequencies matching their tinnitus pitch—turning down the volume of their tinnitus.

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.