What Are the 20th Century's Most Important Inventions?

 

The Most Important Inventions of the 20th Century

The 20th century saw more rapid advances in technology than any other period in history. Two world wars accelerated progress in tanks, aircraft, electronics and atomic weapons.

The telegraph, radio and transoceanic cables revolutionized worldwide communication, impacting government, business, warfare, news media and travel. These and other inventions changed our lives forever.

1. Magnifying Lenses

A magnifying glass is a familiar tool used to examine insects, flowers or whatever else merits close observation. But it's easy to forget just how remarkable these optical instruments are. Magnifying lenses have allowed us to see a wide range of things that would otherwise remain invisible, from distant stars and galaxies to the minute workings of living cells. Magnifying glasses began to appear in the 13th century as aids for people with poor eyesight, and scientists like Robert Hooke, Anton van Leeuwenhoek and Galileo Galilei developed them into microscopes and telescopes to allow deeper observations of life on Earth and beyond.

Optical devices can be made of glass or plastic, and are sometimes coated with anti-reflective coatings to improve image clarity. Magnification depends on the ratio of the parent object size to that of the magnified object, and the quality of magnification also depends on how close the lens is held to the eye. Simple magnifying glasses are typically constructed as spherical biconvex lenses, which provide good magnification with a not too large field of view. There are also a variety of improved multi-lens designs, such as Fresnel lenses (used in lighthouses) and thin sheet magnifiers, that can achieve higher magnification (up to 30x), but with reduced image quality.

Modern magnifying glasses often feature resin lenses, which are lightweight and unbreakable. This makes them more comfortable to use, especially when worn for extended periods of time as with magnifying glasses for jewelry making or stamp and coin collecting. A number of different styles are available, and even children's magnifying glasses are now often made with plastic lenses for ease of use and to encourage interest in science and exploration.

Another of the most important inventions of the 20th century was electric power. The development of long-lasting, efficient, pollution free electricity provided a new source of energy that transformed the way people lived and worked around the world. It allowed for the invention of new industrial, agricultural and communications systems that changed the lives of people everywhere. This was a major step towards a more environmentally friendly world, and one that will hopefully continue to be improved as technology advances in the future.

2. Internal Combustion Engine

Almost all of the vehicles on this planet, from cars to trucks to trains to spacecraft, run on internal combustion engines. This invention revolutionized transportation and powered one of the most significant periods in human history, the Industrial Revolution.

The modern engine is a complex machine that consists of multiple parts, including a cylinder, pistons, connecting rods and flywheel. What powers those pistons up and down are thousands of tiny controlled explosions that occur each minute. This is what makes a car or airplane move, and it is also the power source for lawnmowers, chain saws, snow blowers, pressure washers and other small engines.

In order for these small engines to work, they must have three separate phases of operation: intake, compression and power. The first happens when air and fuel are sucked into the cylinder, followed by the igniting of the fuel in the second phase of the cycle. This results in a buildup of hot gases that push down on the pistons, which is known as the power stroke. Finally, the exhaust stroke occurs when those hot gases are expelled from the cylinder.

There are many variations on this basic design, such as the Wankel engine, which has a triangular rotor that orbits in an epitrochoidal (figure 8 shape) chamber around an eccentric shaft. Another variation is the Bourke engine, which uses a pair of pistons integrated to a Scotch yoke that transmits reciprocating force through a specially designed bearing assembly to turn the crank mechanism. This allows the four strokes of intake, compression, power and exhaust to happen in different locations.

Then there are the jet engines, which use a combination of thrust and aerodynamics to accelerate an object. These are the engines that propel commercial, military and private aircraft, as well as rockets and spacecraft. They are what give us the ability to travel long distances and to live beyond the confines of our planet.

3. Television

Whether it's a reality show, a sports game, or a political debate, there is no doubt that television has revolutionized the world. It is one of the most important inventions of the 20th century, providing both news and entertainment to billions of people worldwide. It is also a powerful medium for advertising, and has greatly affected popular culture in the form of movies, music, and television shows.

Unlike some of the other more significant inventions, which have had an almost immediate impact on society, TV took a long time to develop. In fact, when it was first introduced, many were skeptical of its usefulness. As early as 1880, an article in the journal Nature claimed that it was impossible for a television system to be made.

In spite of this skepticism, TV's development continued. The basic concept was that a photoelectric cell would scan across the image to be transmitted, blocking out reflected light as it went. Then it would move to a different part of the image and repeat the process, transmitting only a line at a time. Eventually, it would be possible to transmit a full picture with a single wire or channel.

The television as we know it today was largely the invention of John Logie Baird. He was able to create the first mechanically scanned color transmission in 1929, using three complete systems of photoelectric cells, amplifiers, glow-tubes and filters, and a commutator to alternate their illumination. He was able to send a 120-line image from his Crystal Palace studios to a projection screen at London's Dominion Theatre.

Although the earliest televisions were large, floor-standing console models that could only be seen from a certain point in a room, by the mid-1930s, the technology had become more compact and portable. GE's relatively compact Porta-Color set, for example, was available in 1936.

Although the airplane is not as widespread as the television, it ranks highly on this list of the most important inventions of the 20th Century because it changed transportation in countless ways. Airplanes have made travel faster and safer, and they opened up whole new industries like tourism, media, communication and even business.

4. Airplanes

Airplanes have brought the world together in unprecedented ways and continue to open up new horizons for travel, commerce and communication. Invented in 1903 by Wilbur and Orville Wright, the airplane actualized a concept previously reserved only for mythological stories. It is a major invention that has changed the way we live forever.

The airplane’s ability to fly is made possible by two opposing forces, lift and drag. The wings of a plane generate lift by dragging the surrounding air, while the weight of the aircraft and its payload creates drag that opposes its motion. The pilot controls the aircraft’s direction by changing the airflow over its wings and using the rudder to maneuver.

When designing an airplane wing, its shape must be optimized to obtain the desired result. This process requires the consideration of a great number of factors such as angle of incidence, chord of the wing, thickness of the wing and surface area. The result is a design that combines both beauty and efficiency.

Typically, planes are powered by engines, although a few use hot air or other types of fuel. The engines are located in the tail of the airplane, producing a central axis of rotation that helps to control the aircraft. The engines produce power by converting chemical energy into mechanical energy. The engine also produces heat, which can be used to produce steam for other purposes.

While the development of engines was relatively fast, other important inventions took longer to become practical. The Haber-Bosch process, for example, converts atmospheric nitrogen (N2) and hydrogen (H) into usable ammonium. That is why you can find ammonium nitrate in your Miracle-Gro bags and lawn fertilizers.

The 20th century was a prolific time for inventions that improved on existing technology and created entirely new ones. Among teenagers, when asked to select five of the most important inventions of the century, 32 percent cited the personal computer, 26 percent picked the pacemaker and 18 percent chose wireless communications. Other inventions on this list include the radio, television and nuclear energy. Interesting Engineering will examine these and other key 20th century inventions in future articles.