20th-Century Inventions That Changed the World

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Glider being launched
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In many ways, the 20th century was defined by groundbreaking scientific discoveries and revolutionary new technologies. When the century began, the industrialized world was still using the steam engine, and as it came to a close, the digital age had ushered in transformational new inventions. From the airplane and the era of high-speed travel to the personal computer and our modern information age, the innovations of this era fundamentally changed the fabric of people’s everyday lives. Here are five transformative inventions from the 20th century.

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The Electric Refrigerator

Today the electric refrigerator is so commonplace, you would barely give it a second thought, but when it was first invented, this humble appliance completely changed the way people lived. The first electric fridge designed for home use was patented in 1913 by an American engineer named Fred Wolf, and by the 1960s the technology had advanced enough for fridges to become a fixture in most U.S. homes. The new kitchen staple transformed nearly every aspect of the way Americans bought, stored, and shipped food. Before the fridge, if you didn’t live near the source of certain perishable foods, it often meant you simply couldn’t get them. Refrigeration made it possible to ship fresh food over long distances without spoilage. It also meant that people could store certain foods year-round without resorting to time-consuming, taste-altering preservation processes such as drying or pickling. Today, electric refrigerators can be found in 99.5% of American homes, allowing people to eat foods from all over the world, pretty much whenever they want — a way of life that would have been unrecognizable to someone living at the turn of the 20th century.

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The Television

When the first fully electronic television system was created by American inventor Philo Farnsworth in 1927, it altered the media landscape forever. The TV made it so that for the first time in history, people could witness significant political and historical events as they were actually happening. Footage of world-changing moments — from Neil Armstrong’s first steps on the moon to the fall of the Berlin Wall — could be broadcast directly into people’s homes instead of merely described over the radio or summarized after the fact in a newspaper. TV didn’t just change the way people consumed their news, of course; it also gave rise to a whole new form of entertainment. Entirely new storytelling formats — from the sitcom to the hour-long prestige drama of the modern era — were created especially for the small screen and gobbled up by millions of viewers around the world, transforming popular culture in the process.

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5 Inventions That Came Out of the Great Depression

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Old car radio
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The Great Depression began in 1929 and lasted for an entire decade, affecting nearly every aspect of daily life for people all over the world — and hitting the United States especially hard. U.S. unemployment soared to nearly 25%, businesses shuttered, and families lost their life savings. Food became scarce in many communities, especially as a severe drought hit the Great Plains, leading to the agricultural disaster known as the Dust Bowl.

This difficult era also impacted innovation. Independent inventors found themselves with less funding, and many businesses shied away from risky initiatives, but big inventions also helped keep companies and innovators afloat during the hard times. Some inventions were successful specifically because of the economic downturn, such as the groundbreaking new adhesive that could repair just about anything. For others, success came in spite of the crisis. Here are five inventions that came out of the Great Depression that are still shaping our lives today.

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Sliced Bread

A century ago, people had to bust out a bread knife whenever they wanted a sandwich or slice of toast. That changed in 1928, when a bread slicing and wrapping machine invented by Otto Rohwedder made its debut at a bakery in Chillicothe, Missouri. The machine proved to be so popular that Rohwedder had trouble keeping up with demand from other bakeries. After the Depression hit, economic realities forced him to sell his patent to a larger manufacturing company — but the story has a happy ending. The owners hired the inventor as the vice president and sales manager of a new division formed just for his machines. In 1930, Wonder Bread started advertising its own sliced bread, and, although Wonder Bread used its own machines, Rohwedder’s bread-slicer sales exploded as the trend grew. By 1933, sliced bread accounted for 80% of all bread sales. The invention was so influential, it led to the phrase still used to praise new wonders today: “The best thing since sliced bread.”

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Nylon Stockings and Toothbrushes

Before the Depression, the DuPont chemical company had a “fundamental research” program — a team of scientists tasked with increasing scientific knowledge rather than developing specific projects. But with the economic downturn, the division became more focused. It was already working on synthetic textiles and had invented neoprene, although the material wasn’t particularly useful at the time. They’d also worked with rayon, which didn’t make a great substitute for silk, and was only partially manmade. Nylon was the first entirely synthetic fiber developed by DuPont that was actually useful — and its invention in 1937 was a very bright prospect after the agricultural woes of the era.

Nylon started appearing in toothbrushes in 1938, and DuPont showed off its new fabric to the world as hosiery at the 1939 New York World’s Fair. The first day nylon stockings became available to the public, around 800,000 pairs flew off the shelves. DuPont’s Depression-era investment in fiber technology paid off; by 1937, 40% percent of its sales came from products that didn’t exist before 1929, including freon, neoprene, and lucite.

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What Did Leonardo da Vinci Invent?

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Etching of Leonardo da Vinci
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In the history of humankind, there are few people who have rivaled the sheer genius of Leonardo da Vinci. The Italian polymath defined the High Renaissance period at the turn of the 16th century, when his fame grew primarily due to his paintings. His magnum opus, the “Mona Lisa,” which he painted between 1503 and 1506, ranks among the most famous paintings of all time, and no religious artwork has been more reproduced than his masterpiece “The Last Supper.” 

But Leonardo was far more than a supremely talented artist. As an engineer, inventor, and student of seemingly everything, he left behind an incredible 5,000 pages of notes and drawings covering everything from human and animal anatomy to astronomy, botany, cartography, and more. His inventions, many of which were designed with military applications in mind, were truly visionary. Few of them were built during his lifetime or saw any practical use, but they were so far ahead of their time it’s almost as if Leonardo was seeing aspects of the modern world long before they came to fruition. Here are five of his greatest creations — designs that display the undeniable genius of the ultimate Renaissance man. 

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The Ornithopter: Leonardo da Vinci’s Flying Machine

Some 400 years before the Wright brothers took flight in the first successful motor-operated airplane, Leonardo da Vinci was already designing flying machines. He wasn’t the first to do this, but he was the most thorough and inventive. He studied the flight of birds and bats, which he used to inform the design of his ornithopter — a device that flies by flapping its winged appendages. Leonardo never built his design, but his ideas regarding flying machines, bird flight, and the nature of air itself were centuries ahead of their time. His studies, which consisted of more than 35,000 words and 500 sketches, included concepts such as the nature of stalling in flight, the relationship between a curved wing section and lift, and the concept of air as a fluid. Incredibly, he even came close to suggesting the force that Isaac Newton would later define as gravity. Leonardo’s fascination with flight also led him to design a primitive parachute and a device known as a “helical air screw,” which bears some similarities to a helicopter.  

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