Humans have dreamed up and created some amazing — and sometimes unorthodox — inventions. From the moment someone bashed a rock on the ground to make the first sharp-edged tool, to the debut of the wheel to the development of Mars rovers and the Internet, several key advancements stand out as particularly revolutionary. Here are our top picks for the most important inventions of all time, along with the science behind the invention and how they came about.
Before the invention of the wheel in 3500 B.C., humans were severely limited in how much stuff we could transport over land, and how far. The wheel itself wasn't the most difficult part of "inventing the wheel." When it came time to connect a non-moving platform to that rolling cylinder, things got tricky, according to David Anthony, a professor of anthropology at Hartwick College.
"The stroke of brilliance was the wheel-and-axle concept," Anthony previously told Live Science. "But then making it was also difficult." For instance, the holes at the center of the wheels and the ends of the fixed axles had to be nearly perfectly round and smooth, he said. The size of the axle was also a critical factor, as was its snugness inside the hole (not too tight, but not too loose, either).
The hard work paid off, big time. Wheeled carts facilitated agriculture and commerce by enabling the transportation of goods to and from markets, as well as easing the burdens of people travelling great distances. Now, wheels are vital to our way of life, found in everything from clocks to vehicles to turbines.
This key invention dates back more than 2,000 years to the Ancient Roman period and became possible only after humans developed the ability to cast and shape metal. Previously, wood structures had to be built by interlocking adjacent boards geometrically a much more arduous construction process.
Until the 1790s and early 1800s, hand-wrought nails were the norm, with a blacksmith heating a square iron rod and then hammering it on four sides to create a point, according to the University of Vermont. Nail-making machines came online between the 1790s and the early 1800s. Technology for crafting nails continued to advance; After Henry Bessemer developed a process to mass-produce steel from iron, the iron nails of yesteryear slowly waned and by 1886, 10 percent of U.S. nails were created from soft steel wire, according to the University of Vermont. By 1913, 90 percent of nails produced in the U.S. were steel wire.
Meanwhile, the invention of the screw - a stronger but harder-to-insert fastener - is usually ascribed to the Greek scholar Archimedes in the third century B.C., but was probably invented by the Pythagorean philosopher Archytas of Tarentum, according to David Blockley in his book “Engineering: A Very Short Introduction” (Oxford University Press, 2012).
Ancient mariners used the stars for navigation, but this method didn’t work during the day or on cloudy nights, making it dangerous to travel far from land.
The first compass was invented in China during the Han dynasty between the 2nd Century B.C. and 1st Century A.D.; it was made of lodestone, a naturally-magnetized iron ore, the attractive properties of which they had been studying for centuries. However, it was used for navigation for the first time during the Song Dynasty, between the 11th and 12th centuries,
Soon after, the technology to the West through nautical contact. The compass enabled mariners to navigate safely far from land, opening up the world for exploration and the subsequent development of global trade. An instrument still widely used today, the compass has transformed our knowledge and understanding of the Earth forever.
The printing press
German inventor Johannes Gutenberg invented the printing press sometime between 1440 and 1450. Key to its development was the hand mold, a new molding technique that enabled the rapid creation of large quantities of metal movable type. Though others before him — including inventors in China and Korea — had developed movable type made from metal, Gutenberg was the first to create a mechanized process that transferred the ink (which he made from linseed oil and soot) from the movable type to paper.
With this movable type process, printing presses exponentially increased the speed with which book copies could be made, and thus they led to the rapid and widespread dissemination of knowledge for the first time in history. In her book “The Printing Revolution in Early Modern Europe” (Cambridge University Press, 2012), late historian Elizabeth L. Eisenstein wrote, “printers’ workshops would be found in every important municipal center by 1500.” It has been estimated that up to twenty million volumes had been printed in Western Europe by 1500, although Eisenstein estimates that it was around eight million.
Among other things, the printing press permitted wider access to the Bible, which in turn led to alternative interpretations, including that of Martin Luther, whose "95 Theses" a document printed by the hundred-thousand sparked the Protestant Reformation.
The internal combustion engine
In these engines, the combustion of fuel releases a high-temperature gas, which, as it expands, applies a force to a piston, moving it. Thus, combustion engines convert chemical energy into mechanical work. Decades of engineering by many scientists went into designing the internal combustion engine, which took its (essentially) modern form in the latter half of the 19th century. The engine ushered in the Industrial Age, as well as enabling the invention of a huge variety of machines, including modern cars and aircraft.
Pictured are the operating steps of a four-stroke internal combustion engine. The strokes are as follows: 1) Intake stroke — air and vaporised fuel are drawn in. 2) Compression stroke - fuel vapor and air are compressed and ignited. 3) Power stroke — fuel combusts and the piston is pushed downwards, powering the machine. 4) Exhaust stroke — exhaust is driven out.
Several inventors did pioneering work on electronic voice transmission - many of whom later filed intellectual property lawsuits when telephone use exploded - but it was Scottish inventor Alexander Graham Bell who was the first to be awarded a patent for the electric telephone on March 7 1876 (his patent drawing is pictured above). Three days later, Bell made the first telephone call to his assistant, Thomas Watson, saying "Mr Watson, come here — I want to see you," according to author A. Edward Evenson in his book, “The Telephone Patent Conspiracy of 1876: The Elisha Gray-Alexander Bell Controversy and Its Many Players” (McFarland, 2015).
Bell’s inspiration for the telephone was influenced by his family. His father taught speech elocution and specialized in teaching the deaf speak, his mother - an accomplished musician - lost her hearing in later life and his wife Mabel, who he married in 1877, had been deaf since the age of five, according to Evenson. The invention quickly took off and revolutionized global business and communication. When Bell died on August 2, 1922, all telephone service in the United States and Canada was stopped for one minute to honor him.
The light bulb
The invention of the light bulb transformed our world by removing our dependence on natural light, allowing us to be productive at any time, day or night. Several inventors were instrumental in developing this revolutionary technology throughout the 1800s; Thomas Edison is credited as the primary inventor because he created a completely functional lighting system, including a generator and wiring as well as a carbon-filament bulb like the one above, in 1879.
As well as initiating the introduction of electricity in homes throughout the Western world, this invention also had a rather unexpected consequence of changing people's sleep patterns. Instead of going to bed at nightfall (having nothing else to do) and sleeping in segments throughout the night separated by periods of wakefulness, we now stay up except for the 7 to 8 hours allotted for sleep, and, ideally, we sleep all in one go.
It's one of the most famous discovery stories in history. In 1928, the Scottish scientist Alexander Fleming noticed a bacteria-filled Petri dish in his laboratory with its lid accidentally ajar. The sample had become contaminated with a mold, and everywhere the mold was, the bacteria was dead. That antibiotic mold turned out to be the fungus Penicillium, and over the next two decades, chemists purified it and developed the drug penicillin, which fights a huge number of bacterial infections in humans without harming the humans themselves.
Penicillin was being mass-produced and advertised by 1944. This poster attached to a curbside mailbox advised World War II servicemen to take the drug to rid themselves of venereal disease.
About 1 in 10 people have an allergic reaction to the antibiotic, according to a study published in 2003 in the journal Clinical Reviews in Allergy and Immunology; even so, most of those people go on to be able to tolerate the drug, researchers said.
Related: What causes allergies?
Not only have birth control pills, condoms and other forms of contraception sparked a sexual revolution in the developed world by allowing men and women to have sex for leisure rather than procreation, they have also drastically reduced the average number of offspring per woman in countries where they are used. With fewer mouths to feed, modern families have achieved higher standards of living and can provide better for each child. Meanwhile, on the global scale, contraceptives are helping the human population gradually level off; our number will probably stabilize by the end of the century. Certain contraceptives, such as condoms, also curb the spread of sexually transmitted diseases.
Natural and herbal contraception has been used for millennia. Condoms or ‘sheaths’ have existed in one form or another since ancient times, according to scholar Jessica Borge in her book “Protective Practices: A History of the London Rubber Company and the Condom Business” (McGill-Queen’s University Press, 2020), with the rubber condom developed in the 19th century. Meanwhile, the FDA approved the first oral contraceptive pill in the United States in 1960 and by 1965, more than 6.5 million American women were on the pill, according to author Jonathan Eig in his book, “The Birth of the Pill: How Four Pioneers Reinvented Sex and Launched a Revolution” (W. W. Norton & Company, 2015).
Scientists are continuing to make advancements in birth control, with some labs even pursuing a male form of "the pill." A permanent birth-control implant called Essure was approved by the Food and Drug Administration in 2002, though in 2016, the FDA warned the implant would need stronger warnings to tell users about serious risks of using Essure.
Related: 7 surprising facts about the pill
The internet is a global system of interconnected computer networks that is used by billions of people worldwide. In the 1960s, a team of computer scientists working for the U.S. Defense Department's ARPA (Advanced Research Projects Agency) built a communications network to connect the computers in the agency, called ARPANET, the predecessor of the internet. It used a method of data transmission called "packet switching", developed by computer scientist and team member Lawrence Roberts, based on prior work of other computer scientists.
This technology was progressed in the 1970s by scientists Robert Kahn and Vinton Cerf, who developed the crucial communication protocols for the internet, the Transmission Control Protocol (TCP) and the Internet Protocol (IP), according to computer scientist Harry R. Lewis in his book “Ideas That Created the Future: Classic Papers of Computer Science” (MIT Press, 2021). For this, Kahn and Cerf are often credited as “inventors of the internet”.
In 1989, the internet evolved further thanks to the invention of the World Wide Web by computer scientist Tim Berners-Lee while working at CERN (The European Organization for Nuclear Research). According to CERN, "the basic idea of the WWW was to merge the evolving technologies of computers, data networks and hypertext into a powerful and easy to use global information system." The development of the WWW opened up the world of the internet to everybody and connected the world in a way that it had never been before.