Before the invention of transistors, vacuum tubes made radio possible

The first computers performed calculations using lightbulb-like tubes

Before transistors, the first electronic computers relied on vacuum tubes—components that switched signals on and off. Despite machines like ENIAC—the first programmable, general-purpose, electronic computer—utilizing nearly 18,000 tubes that generated massive amounts of heat and frequent failures, they laid the foundation for modern computing hardware.

Tesla's alternating current power's most of the world's electric grids

In 1879, Thomas Edison’s light bulb relied on direct current, but such currents can't efficiently transmit power over long distances. Nikola Tesla introduced alternating current, which feature far fewer energy loses. Despite Edison’s attempts to discredit AC, Tesla proved its efficiency by lighting the 1893 Chicago World’s Fair.

Transistors are the foundation of electronic signal processing

Small amounts of voltage can allow or block the flow of electrons across a transistor made from modified layers of semiconducting materials. The conducting (1) and insulating (0) states can be quickly modified as binary code is processed in a computer system.

The Tesla coil was the first system to wireless transmit electricity

Developed in 1891, the system effectively consists of two open electric circuits with a gap of air between them. When a high enough voltage is built up, air becomes a conductor and sparks of electricity are generated.

A collective effort from multiple scientists and inventors led to the light bulb

While Thomas Edison's thin carbon filament design made light bulbs commercially viable, prior contributions, such as Joseph Swan's development of the first successful incandescent filament electric lamp, made its eventual invention possible.

Cathode rays are beams of electrons that emit light when hitting a fluorescent screen

When these beams are emitted into an evacuated tube containing charged plates or a nearby magnet, deflections are observed due to the electron charge. In 1897, J.J. Thomson's calculations of this deflection led to his discovery of the subatomic particle.

IFA 1931 hosted the first public TV demonstration

In 1931, Manfred von Ardenne presented his cathode ray tube television to the public for the first time, marking the first public demonstration of fully electronic TV. This article examines his breakthrough and the evolution of television technology since.

The disputed inventor of the radio

Guglielmo Marconi was awarded the 1909 Nobel Prize in physics for inventing the wireless telegraph, which used radio waves to transmit Morse code. Nikola Tesla, however, was experimenting with radio waves in the 1890s, though much of his work was destroyed in a 1895 fire.

Electromagnetic induction creates electricity from a changing magnetic field

The phenomenon was discovered in 1831 by Michael Faraday when an electric current was induced in a wire wrapped around an iron ring after a second wrapped wire not connected to the first was connected or disconnected from a battery.

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.

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.

Radioactive elements can generate electricity, sterilize products, and date artifacts

Since their discovery in the 1890s, these substances have been incorporated throughout our daily lives, from treating food packaging and improving microbial safety to their presence in smoke detectors and gauges for ice cream aeration.

Thomas Edison, eager to communicate with ghosts, tinkered with an apparatus called the 'spirit phone'

The inventor was interested in developing a scientific method for communicating with the dead. He was not interested, though, in the occult figures who believed the dead could be reached through Spiritualism, which he found childish. He believed those kinds of people "permit themselves to become, in a sense, hypnotized into thinking that their imaginings are actualities."

The electric microphone led to a country music boom

The electric microphone provided enhanced audio and greater portability, saving the fledgling record industry and making recording outside of New York and Camden, New Jersey, possible. This proved critical for capturing early country and rock ‘n’ roll.

Benjamin Franklin described a series of static electricity storage jars as 'batteries'

Discovered over 50 years before the first electrochemical cell was invented, Leyden jars stored electric charge between the metals inside and outside a liquid-filled container. Franklin was the first to use the term "battery" in an electrical sense, though his multiple-jar device—lacking chemical reactions—was actually a series of capacitors.

X-rays earned the very first Nobel Prize in physics for revealing hidden worlds

In 1895, Wilhelm Conrad Röntgen discovered X-rays, which could pass through solid objects and make unseen structures visible. Today’s X-ray tools continue to advance science and medicine, including capturing real-time images of proteins.

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.

RTGs convert heat generated by the decay of radioactive plutonium into electricity

Radioisotope thermoelectric generators use a thermocouple—two plates of different metals joined at two junctions to make a closed circuit. When heating one junction while keeping the other cool, a voltage and an electric current are created.

Contactless credit cards descend from a batteryless Cold War listening device

The same physics that let Soviet spies eavesdrop on the US ambassador in 1945 underlie contactless payment methods today. The device is a passive chip powered wirelessly by incoming radio waves.

Why were tanks invented?

Tanks first appeared in warfare in World War I. As old methods of conducting battles proved ineffective, the idea of an armored vehicle that could traverse almost any terrain and carry a cannon came to fruition. World War I provided the impetus and finances to develop the modern tank. Learn more in this short but detailed article.

Silicon Valley’s history in technology can be traced back to the late 1800s

From its developments in radio, defense technology, and personal computing, Silicon Valley has been associated with innovating tech for more than a century. This animated timeline of Silicon Valley’s history helps visualize its evolution.

Tracing the history of refrigeration

Refrigeration has become critical to most of our lives. But not long ago, it wasn't available. How did we become so dependent on our fridges and freezers? This fun, informative podcast traces the history of keeping it cool with ice and...

The transatlantic cable allowed for communications between North America and Europe

It had significant impacts on just about every industry, including finance. Specifically, the transatlantic cable made it so that real-time financial transactions could take place across the Atlantic, and allowed for much faster sharing of information that increased global market accuracy.

The simplicity of immersed tube tunnels

Tunnels have traditionally bored holes through the earth below the water. On the other hand, immersed tube tunnels connect hollow, massive sections in trenches along the floor of the body of water. Each section is built on land, floated to the site, submerged, and connected. This method saves money by reducing expensive underground work, and it preserves an area's aesthetic appearance.

Before vaccines, there was 'variolation': what was it?

Before the technology behind vaccinations was discovered, some keen observers of medicine around the globe noticed how previous infections could impact future ones. Learn about the techniques early physicians used before they had vaccines.

Samuel O’Reilly patented the tattoo gun in 1891

Before the tattoo gun's invention, recipients sweated while artists slowly tapped or sliced designs into their flesh. The tattoo gun changed the field, helping artists ink clients’ skin at incredible speeds. Inventor Samuel O’Reilly applied the basic idea of an electric pen invented by Thomas Edison to his tattoo gun.

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 name 'Silicon Valley' arose from the founding of Shockley Semiconductor Laboratory in Fairchild Semiconductor in 1956-57, founded near Stanford University in Palo Alto

Walt Disney's early film 'Alice's Wonderland' was a groundbreaking innovation in the silent film era

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

Learn more about the history of fireworks, which dates back to an accidental invention during an alchemist's quest for information about immortality.

Sony set the standard for cylinder-shaped batteries when it repurposed manufacturing equipment used to make rolls of magnetic recording tape.

English mathematician Ada Lovelace wrote the first computer algorithm a century before computers existed and hypothesized that computing devices would one day be able to compose music—foreseeing the generative AI systems of today.

Planeterrellas create artificial auroras that mimic the atmospheric displays of light by setting up an electric field between two metal balls in a jar filled with a small amount of air.

Discover the catastrophic consequences of a failure of the US electrical grid—something that is more likely than many Americans think.

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.

Against his wishes, Albert Einstein's brain was removed before his cremation, and the pathologist responsible stored it for decades in mason jars within a beer cooler.

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.

While the first exchange-traded fund (a 'basket' of different assets that can be bought and sold on a stock exchange) in the US only launched in 1993, the global ETF market has grown to more than $10T in the short time since.

Long before Major League Baseball began allowing instant replay for balls and strikes, an umpire reluctantly used the technology to determine whether a hit was a home run, a move that inadvertently ushered in a new era for the sport.

A researcher recently discovered an interview from 1967 between groundbreaking journalist Joan Didion and the Grateful Dead, years before the band became an institution.

After the Boston Tea Party, colonists switched to coffee, which became the main morning drink for revolutionaries.

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

Objects can be 3D printed with light by projecting 2D computerized tomography (CT) scans onto rotating cylinders of resin, which solidify upon exposure.

The Mona Lisa's celebrity status and repeated restorations have obscured what made the painting so revolutionary for its time

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

Sears sold DIY house kits starting at $600 in its famous catalog from 1908 through the 1940s, resulting in roughly 10,000 'Sears and Roebuck houses' being built.

Stanford built a Google Maps for the Roman Empire, revealing how much it cost to travel in the ancient world

Warren Buffett's former professor Benjamin Graham is known as the 'father of value investing,' a strategy in which investors seek to buy stocks trading below their intrinsic worth.

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.