Why breathing helium, sulfur hexafluoride, and other gases changes your voice

Why helium mixtures are used in respiratory medicine

Unlike the air near Earth's surface, which is primarily composed of oxygen and nitrogen, heliox is composed entirely of oxygen and helium. Because helium is lighter than nitrogen, the lungs do not have to work as hard to push air, easing the uptake of oxygen via a ventilator, mask, or nasal tube.

Why you may hate the sound of your voice

It's a relatively common experience to cringe while listening to a recording of your own voice. This Popular Science article offers physiological explanations for the discrepancy between what we hear when we speak versus what others hear. The piece also expands on the psychology behind this discontent, and how our voices influence our self-perception and social interactions.

Variations in rapidly expanding gas and mechanical elements produce fireworks sounds

Chemical compounds designed to vibrate rapidly when ignited produce whistling, screeching sounds, while crackles and pops are created by small star pellets inside the firework, which explode one after another quickly. Fluttering and chirping sounds are produced by spinning elements that rotate rapidly as the firework ascends.

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.

The features that make our voices unique

Human voices are about as unique as fingerprints: similar instruments but with endless variations. We each produce sound in the same physiological way, but when we talk we’re dropping clues about who we are, what we do, and where we’re from.

Why trying to freeze helium creates a fluid that can travel through solids and climb walls

Once cooled to temperatures just above 2 Kelvin, helium-4 atoms begin to exhibit superfluidity, a quantum property in which all atoms collectively inhabit the same low-energy state and behave in perfect unison. This coordination removes the internal friction that causes liquids to cling to surfaces, allowing them to slide through microscopic pores and scale container walls.

Why stories about helium 'running out' indicate market volatility rather than scarcity

Only a few locations on Earth contain natural gas reserves with sufficiently high helium concentrations to make their extraction commercially viable, and geopolitical conflicts in these areas significantly affect helium production. This makes cost a major impediment to helium availability, particularly for scientific research, amid growing demand and ongoing depletion of reserves that took billions of years to form.

What did Ötzi the Iceman sound like?

The natural pitch of a person's voice depends on the size of their larynx, also known as their voice box, and the length and thickness of their vocal folds or vocal cords. Using this information, scientists have recreated the voice of Ötzi the...

Sound can shatter glass if its frequency matches the material's natural vibrations

The sound made by an object when struck is its resonant frequency, which is the sound made when energy is dissipated. Providing energy at that frequency amplifies the vibrations, rather than allowing them to dissipate, which can deteriorate the object's structural integrity.

Billie Holiday's distinctive vocal technique was aided by new microphone technology

Unlike many of her contemporaries, Holiday's voice was more reserved and seductive. In the past, that wouldn't have been practical—earlier microphones required singers to belt in order to be heard throughout a club or theater. However, technological breakthroughs in the 1930s produced more sophisticated and sensitive microphones, enabling a singer like Holiday to experiment with vocal dynamics.

Ambient sounds on Mars are lower-pitched and more muted than those on Earth

The planet's thin atmosphere absorbs higher frequencies, and audio captured by the Perseverance rover from the Ingenuity Mars helicopter revealed that sound waves travel farther than previous atmospheric models suggested.

Fireworks make a loud booming sound after exploding due to air expanding faster than the speed of sound.

Modern sound mixing has contributed to audiences needing subtitles

Hidden, high-tech microphones allow actors to speak more softly, rather than yelling to be picked up by a distant boom mic, but this sacrifices clarity. The problem is exacerbated by mixing often prioritizing booming sound effects and soundtracks and audiences listening with small speakers on mobile devices.

How Stephen Hawking’s voice became iconic

Stephen Hawking relied on a voice synthesizer after losing the ability to speak due to complications with ALS. Despite technological advances, he refused to change the "Perfect Paul" voice, making it a cornerstone of his public identity.

How geometry and uneven charge distribution make some molecules greenhouse gases

Molecules vibrate and rotate with different frequencies based on their elemental composition and shape, which can produce uneven distributions of electrons, as seen in carbon dioxide and water. The resulting unbalanced electric field can interact with electromagnetic waves of the same frequency, causing the molecule to absorb the radiation.

The science behind why some noises have color names

Different noise colors (white, brown, pink, blue) have been proven to affect mood and focus. An audiologist explains that these sounds are named after specific light wave frequencies. While individual preferences vary, certain noises consistently impact sleep, stress reduction, cognitive performance, and problem-solving. The article highlights how these sounds can enhance productivity, relaxation, and even gaming experiences.

Listen to recordings of different fish species

Scientists have captured and curated this collection of species-specific recordings, helping us gain a deeper understanding of underwater ecosystems. Uncover their sounds, which include a lot of thumps, burps, and grunts.

Solar activity and the density and chemical composition of the air affect auroral colors

Oxygen atoms can emit red and green light when energized by collisions with the solar wind, but red takes longer to be emitted and is disrupted by bumping into other molecules. This causes red light to appear at higher altitudes, where the air is less dense. Higher-energy solar wind can penetrate to lower altitudes and collide with more abundant ionized nitrogen, which produces blue light.

How water pressure affects the body

The extreme conditions of the deep sea include increasing amounts of pressure as explorers and organisms descend into its depths. The major danger for both fish and humans is the way pressure changes how body tissues absorb chemical molecules...

Space tourism rockets emit up to 100 times more CO₂ per passenger than airplanes

Rocket launches release significant amounts of water vapor, nitrous oxide, and rocket propellants, which generate greenhouse gases and air pollutants. High-altitude emissions can persist for years, affecting the ozone layer.

Understanding time dilation

The faster you go, the slower time ticks for you. And the stronger the gravitational field acting on you, the slower time ticks for you. These phenomena – collectively called time dilation – were first explained by Albert Einstein’s theories of general and special relativity. In this 11-minute video, beloved astrophysicist Neil deGrasse Tyson explains them to comedian Chuck Nice.

Glacial ice loss can be determined by listening to escaping bubbles

Glaciers form from the accumulation of layers of snowfall over hundreds to thousands of years, trapping air bubbles that serve as time capsules of atmospheric conditions at the time. When glaciers melt, these bubbles produce a distinctive sound that can be detected by underwater microphones, allowing assessment of melting from a safe distance.

Distinguishing club soda, seltzer, and sparkling water

The three forms of drinking water are similar, but their differences lie mostly in the presence and proportion of minerals and carbonation. Read this quick explainer on the major differences.

Stars appear to twinkle because turbulence in the motion of molecules in Earth's atmosphere causes light to bend and wiggle rapidly on its way to the surface—a phenomenon called scintillation.

Tone Transfer recreates any piece of audio into instrumental recreations

Using machine learning models and Differentiable Digital Signal Processing, this tool can transform any 15-second sound clip into a flute, saxophone, trumpet, or violin reproduction. Researchers behind the open-source experiment hope the technology will enable musical creation through creative sound combinations.

Ultrasound machines emit and collect high-frequency sound waves to construct images

Before its use in medical imaging, the technology was employed in World War I for submarine detection, the same way bats use sound for echolocation of obstacles. Differences in the penetrating power of different frequencies allow medical professionals to detect different structures in the body.

Fear has a specific 'smell'—at least to machines

This excerpt from a Mythbusters episode takes on the smell-of-fear question, comparing the sweat composition of individuals exposed to snakes, rats, and scorpions with that of people exercising. Molecularly, the sweats are different to a gas chromatography machine, but to most noses would be indistinguishable.

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.

The deadliest aspect of volcanic eruptions is often not lava, but pyroclastic flows—avalanches of ash, gas, and rock that can move more than half the speed of sound.

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.

The price of gas is a composite made up of several different factors, with the federal gas tax making up less than 20% of what drivers pay at the pump.

Scientists testing how climate change affects plants found, in a years-long simulation study, that poison ivy grew 70% faster with the resulting extra carbon dioxide.

An investigation suggests a Scottish island became awash in forever chemicals via seafoam and seaspray—raising questions about what that means for the safety of other coastal areas.

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

Double world record holder Hunter Ewen helped conquer his fear of balloons, called globophobia, by training to win Guinness World Record titles for balloon inflation.

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

Most of the observable universe's volume consists of voids and supervoids—enormous regions of space with little to no galaxies, stars, or light.

The word 'jazz' evolved from 'jasm,' 19th-century American slang for 'energy'

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

Massive 3D printers have been used to build homes by stacking layers of 'concrete toothpaste,' a fire-resistant material that effectively insulates against outside noise.

The first horror movie is believed to be George Méliès' 1986 short 'The Haunted Castle,' which pioneered the use of special effects

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.

Existentialist writer Jean-Paul Sartre coined the famous phrase 'Hell is—other people' in his play 'No Exit'

SpaceX's S-1 or 'prospectus' revealed many previously unknown details about the company, including its unprofitability despite doing $18.7B in revenue in 2025, exactly how many voting shares Elon Musk will have in the company (roughly 85%), and more.

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

When a Paris department store hesitated to sell Estée Lauder's perfume, she 'accidentally' broke a bottle, causing the smell to spread throughout the store and shoppers to start asking to buy the scent.

Hear about the 250-year history of the United States Postal Service, complete with some of its strangest deliveries, important innovations, and the figures that made it an American institution.

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.

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

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.