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.

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.

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.

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.

Through sonoluminescence, concentrated sound waves can produce short, high-intensity flashes of light by rapidly collapsing microscopic bubbles to temperatures up to twice that of the sun's surface.

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.

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

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.

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.

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

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.

Studying 'sonic' black holes

If a fish screams as it falls down a cascading waterfall accelerating to ridiculous speeds, will his fish friends above hear him scream? This analogy, odd as it is, has become an essential tool in the astrophysicists kit for learning how enigmatic black holes operate. Lab experiments mirroring the so-called sonic black hole have achieved insights for their cosmic counterparts. Read how it works in this brief piece.

Listen to the pair of colliding black holes detected by LIGO

As ripples in spacetime, gravitational waves do not produce sound, which is the perception of specific vibrations in matter (e.g., vocal cords vibrating air molecules). The "chirp" of gravitational waves comes instead from converting the spacetime ripples into sound waves that the human ear can hear.

An Aztec skull whistle discovered in the 1990s was mistaken for a toy

In the late 1990s, archaeologists unearthed a sacrificed man clutching two skull-shaped clay whistles at a Mexico City temple to the wind god Ehecatl (eh-HEH-kahtl). Initially dismissed as toys, the instruments produce a scream-like sound that modern brain scans show triggers fear and urgency responses in listeners. This podcast explores the discovery.

'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.

A person's voice sounds different when breathing helium, sulfur hexafluoride, or gases other than air because the speed of sound varies with the properties of the material through which it travels.

Listen to the sounds of pulsars, which emit radio pulses up to hundreds of times a second

Just as figure skaters spin faster by tucking in their arms, these celestial objects acquire high rates of spin from the collapse of the cores of massive stars. The star's rotation spins its magnetic field, generating beams of radio waves from its magnetic poles. If either of these poles faces a detector, the signals can be picked up and converted to audio signals.

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.

By igniting flammable gas in a tube filled with holes and playing music into it, the fire will take the shape of the sound waves, enabling the visualization of audio.

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.

'Silent' fireworks have gained more interest in recent years as a quieter celebratory option.

If the Earth stopped spinning, 85% of the world's population would experience supersonic winds

The planet's equator moves about 470 meters per second—over 1,000 miles per hour—and air there would continue moving at this speed for several minutes if the ground stopped rotating. These conditions would cause tsunamis, global storms, and fling debris fast enough to destroy nearly all human-made structures.

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

View the 18 vehicles that broke the land speed record

The battery-powered "La Jamais Contente" was the first car to exceed 100 kilometers (62.1 miles) per hour, achieving the feat in 1899. By 1997, advancements in aerodynamic understanding and engineering led to the Thrust Supersonic Car, a jet-powered vehicle that reached a speed of 1,223.6 kilometers (760.3 miles) per hour.

Oscillating matter in the early universe left behind patterns detailing cosmic expansion

As gravity tried to bring matter closer together in the early universe, its high temperature produced an outward pressure that caused it to expand. These competing forces caused matter to vibrate and produce the equivalent of sound waves, which spread outward as the universe expanded and cooled, serving as relics of dark energy's history.

Squeaky toys mimic prey sounds, appealing to dogs' hunting instincts

Squeaky toys provide instant feedback and gratification, and they can also prevent boredom and improve canine dental health. Some toys contain seemingly silent squeakers that use ultrasonic technology to emit sounds only audible to dogs.

Will-o'-the-wisps may be the result of microlightning between bubbles

Methane and air bubbles moving through water can generate small sparks between them, which can ignite gas. The above-ground phenomenon may have historically been the result of passing travelers igniting swamp gas with their lanterns. (Some readers may experience a paywall.)

Unlike the roars in movies, dinosaurs likely cooed, rumbled, and boomed

Fossil evidence and CT scans suggest that many dinosaurs produced low-frequency sounds using resonating crests, closed-mouth vocalizations, or organs similar to those of birds and crocodiles. Larger sounds would not have been helpful for sneakily hunting prey.

Audi spent over three years developing engine sounds for its electric vehicles

Unlike the sounds made by combustion engines in gas-powered vehicles, electric cars produce no motor sounds. The company's acoustics team worked with composer Rudolf Helpmier to craft an electric-inspired revving sound for its R8 e-tron supercar.

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

The surprising science behind Pop Rocks

Have you ever wondered why Pop Rocks makes tiny explosions in your mouth? Well, there's actually pressurized carbon dioxide bubbles trapped within the sugary candy. This 19-second video shows you what Pop Rocks look like under a microscope.

Light echoes are expanding shells of reflected starlight

Just as sound waves reveal the location of obstacles by reflecting off them, pulses of light emitted by stars illuminate rings of interstellar dust, giving the appearance of ejected material as the light travels outward.

Phil Spector's 'wall of sound' revolutionized girl groups—and pop music

The method captured a room of live musicians and transmitted the sound into a basement outfitted with more speakers and microphones. That sound was then sent into the central control room, producing a massive recording that sounded unlike anything else in pop music.

Some earthquakes can produce smaller tremors called boomerang earthquakes, which travel in the opposite direction and ripple back to the original earthquake's source.

The most popular drum sound of the 1980s was discovered by accident

You know it when you hear it: the distinct snare drum of songs like Phil Collins' "In the Air Tonight" or Bruce Springsteen's "Born in the USA." It's called "gated reverb," and it's something most people associate, for better or worse, with the sound of the '80s. This Vox explainer breaks down how it was discovered by accident, thanks to a microphone typically used for communication that picked up additional sounds.

The collapse of gas bubbles in the joint synovial fluid causes 'cracking' knuckles.

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