How radio works

Why Edwin Armstrong developed FM radio

AM radio was popular but prone to interference and static, which could be frustrating for listeners. In 1933, Armstrong, a Columbia University professor, discovered that a clearer signal could be broadcast by revising how it was captured.

Radio waves are used in broadcasting, weather radar, telecommunications, and GPS

Its ability to bend around obstacles and reflect off the ionosphere—an electrified layer of Earth's upper atmosphere—allows this type of light to travel long distances without damaging living things due to its low energy. MRI scanners, WiFi, and Bluetooth technologies are also applications of this form of light.

Stream live radio from anywhere on Earth

Spin a 3D globe and tune into thousands of live radio stations by clicking any dot on the map. The project is seamless and acts as a reminder that somewhere, right now, someone is broadcasting music, news, or a call-in show in a language you've never heard.

See a timeline of commercial radio history

Radio, as we know it, began in the 1910s. This FCC timeline traces the evolution of the medium over the century that followed, highlighting groundbreaking broadcasts, speeches, and technological breakthroughs.

Despite the popularity of podcasts, most US adults still listen to radio

A 2026 survey found that 84% of adults aged 25-64 report listening to the radio weekly. That's more than double the number of those who listen to podcasts.

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.

The accidental birth of radio astronomy and the benefits of a moon-based telescope

Detecting radio waves from distant celestial objects is complicated by noise from solar wind, which the nighttime side of the moon is shielded from. If lunar temperature extremes can be overcome, the environment may serve as an optimal future home for radio astronomy, a field that began in 1928 when a 30-meter-long directional antenna, mostly out of brass and wood, picked up signals from the Sagittarius constellation.

Distinguishing between natural and artificial, or induced, radioactivity

Naturally occurring radioactivity comes from radioactive elements underground, cosmic radiation from the sun and other objects in space, and radioactive atoms that make up the molecules we breathe, eat, and drink. Artificial radioactivity is predominantly generated for medical applications and industrial activities.

How do 5G base stations work?

5G relies on a combination of base stations, including macrocells, small cells, and femtocells. The differences between the three are apparent in size, coverage, and cost—but, small cells in particular are key to providing the high millimeter wave frequencies 5G promises. Learn more in this three-minute video.

How the Antimatter Factory works, and why antimatter transport is so difficult

At CERN, protons are accelerated to 99.93% the speed of light and collide with iridium to create antiprotons. These particles are then slowed and sent to various research experiments. Moving the antimatter to other locations for study requires trapping it in electromagnetic fields to prevent contact with normal matter, which would cause annihilation.

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.

What (and why) is ASMR?

ASMR podcasts and videos are appearing all over social media, so what exactly is it, and what does it do? This immersive article explains the phenomena of ASMR, which stands for autonomous sensory meridian response. ASMR is when certain sounds or...

During flights, cell phones can act like signal jammers as they search for service

When farther from cell towers, these devices expend more energy to emit more powerful signals, which can overwhelm any ground-based tower or radio telescope they fly past. Rather than protecting the flight, airplane mode conserves a cell phone's battery.

Pierre Curie's knowledge of electromagnetism helped decipher radioactivity

Alongside his brother, he studied electric fields in crystals and the magnetic properties of substances, which required the construction of delicate electrometers. He would use this apparatus with Marie Curie to measure radioactive emissions and the presence of undiscovered radioactive elements.

Noise-canceling headphones cancel out environmental sounds with sound of its own

If sound waves are perfectly out of sync, they can undergo destructive interference, canceling each other out. A microphone in noise-canceling headphones picks up external sounds, and an out-of-sync version is emitted to cancel them out in your ears.

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.

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.

Astronomers use a set of scaffolding methods to measure distances across the universe

Different methods are used depending on how far away an object is—from radar for nearby planets, to parallax for stars, to redshift and supernovae for distant galaxies. These tools allow scientists to chart the universe across unimaginable scales using astronomical units (AU), light-years, and parsecs.

Telenovelas evolved alongside technology

Like soap operas, telenovelas began as radio programs and then transitioned to television as the medium became widely available in Latin American countries.

BBC Radio 4 tackles the history of Stonehenge

On this podcast, host Greg Jenner humorously unpacks Stonehenge’s biggest myths and mysteries—from what a “henge” actually is, to how alien theories emerged, and why the monument was once sold for just £6,000.

The Japanese Navy used radio silence and deception to mask its approach

In late November 1941, Japan’s carrier strike force maintained total radio silence while operators back home broadcast normal traffic—creating ambiguity about the location of the fleet. The deception obscured US intelligence and helped create a surprise attack.

What's the difference between an ale and a lager?

The major distinction is that ales are typically fruitier, while lagers are cleaner and crisper. This video breaks down several more of the nuanced differences between the two styles.

Nine different studies exploring animals' relationship to music

Researchers have conducted multiple studies attempting to answer a certain question: do animals like human music? Across species, they observed different results and no clear pattern. Primates appear to prefer silence, and cockatoos appear to dance to funky beats.

Making sense of Mexico City's traffic honks and horns

A car's horn makes just one sound, but somehow, drivers across the world manage to use the monotone for a surprising variety of purposes. This audio-inflected essay takes readers into the nuanced horns of Mexico City's famously congested traffic, providing a "claxonomy" (taxonomy + claxones, or horns) of its drivers' honks.

How mutual funds work

Mutual funds function similarly to other types of investments. If you want to invest, you go through a brokerage firm. However, they have a few key differentiators. Most are actively managed by a broker instead of passively earning you returns. Plus, they can carry some hefty fees.

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.

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.

Radioactive elements can introduce software errors because the ionizing radiation they produce can detach electrons from atoms, and computer code relies on the distribution of electrons.

The history of many kitchen appliances involves unexpected discoveries and applications, including wartime radar turned hamster defroster and replacing an 'ice king' with heat-stealing boxes.

See how fireworks are made and learn how metals like magnesium and copper are responsible for different colors.

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.

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.

Hedge funds, the private investment firms that trade a wide swath of financial assets, make money by imposing steep fees on investors and from the fund's investment performance.

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

The first image of a black hole was captured by creating an Earth-sized virtual observatory from a network of eight radio telescopes.

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

20,000 letters to the advice columnist 'Dear Abby' provide insight into prevailing sex, religion, and LGBTQ fears, anxieties, and concerns from the 1950s onward.

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

Track the location of the Voyager probes, currently between 13 and 15 billion miles away from Earth.

While El Niño moves warm Pacific Ocean waters east along the equator, La Niña moves them west, shifting where rainfall will become more common for months.

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

A small portion of The Winstons' 'Amen, Brother,' an obscure '60s gospel record, is the basis for thousands of hip-hop tracks, making it one of the most sampled records ever that's informally known as 'the Amen break.'

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

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.

70 years ago today, city officials in Santa Cruz, California, banned rock 'n' roll to protect its youth from corruption after witnessing a 'provocative' concert the night before.

Some coin denominations have ridges etched on their sides, partly to prevent counterfeiting, in a practice called 'reeding.'

The first steps to rebuilding your credit score include getting to know exactly what's on your credit report and figuring out how far you are from the '700 club,' or 'good score' range.

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.

Budweiser stores yeast derived from the original 1800s strain in a secret bunker, which only the Head of Yeast Management can access—not even the CEO

Trace how the Bill of Rights, inspired by centuries of political theory, took shape between 1774 and 1789.