11 Influential Inventions From the 1920s That You Should Definitely Know About

• Edwin Starr might tell you that war is good for absolutely nothing, and it indeed is. Yet, a lot of the technology that we use today was either a direct result of, or evolved from, military applications.
• Both WWI and WWII accelerated technological developments across the world, often based on the need to better understand the enemy and to protect soldiers. 
• We already discussed some of the most interesting inventions from 1911-1920, which were created during and in response to the first World War.

Here, let's take a look at the decade following the end of WWI to see what inventions emerge to shape our lives. Here are some of the most influential and interesting 1920 innovations. 

1. The Headrest

This 1920s technology makes your automobile experience far more comfortable and safer. Invented by Benjamin Katz in 1921, headrests gained immediate widespread popularity due to the comfort and added safety they offered to drivers, eventually leading to the National Highway Traffic Safety Administration making it mandatory to have headrests on all new cars in 1969. 

2. The Convertible 

Now the convertible was not completely new, but Ben P. Ellerbeck is the man credited with creating the first practical and retractable manual hardtop system in 1922. While Parisian Georges Paulin created the first power-operated retractable hardtop in 1934. 

3. The Traffic Light 

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Credit for the "first electric traffic signal" usually goes to James Hoge. A system based on his design was installed on Aug. 5, 1914, in Cleveland. It used the alternating illuminated words "stop" and "move" and was wired to allow police and fire departments to adjust the rhythm of the lights in case of an emergency.

William Ghiglieri of San Francisco patented the first automatic traffic signal that used red and green lights in 1917. Then in 1920, William Potts, a Detroit police officer, developed several automatic traffic light systems, including the first three-color signal, which added a yellow "caution" light.

Three years later, Cleveland resident Garrett Morgan patented an electric automatic traffic signal that used a T-shaped pole with three positions. The idea was sold to General Electric for $40,000 eventually leading to its massive popularity. 

4. Water Skiing 

During the Roaring Twenties, the wealthy and adventurous invented new ways to entertain themselves. Created by Ralph Samuelson in 1922, water skiing evolved into a major beach sporting event, starting with just a pair of boards and a clothesline. 

5. The Audiometer 

Invented by an American physicist Dr. Harvey Fletcher, the audiometer is a device that is used to measure and evaluate hearing loss. Audiometers are used around the world as a standard part of medical equipment in clinics and hospitals. 

6. The Bulldozer

A crucial tool in the world of civil engineering, the bulldozer is used all over the world for construction processes today. The inventors, James Cummings and J.Earl McLeod, built up the machine in Kansas, and it originally consisted of a large blade that could be attached to the front of a tractor. This simple but clever attachment was originally used to dig canals and was patented as ‘Attachment for Tractors’ in 1925. 

7. The Instant Camera

Since its creation, the instant camera has consistently evolved over the years, catching the eyes of each generation. Although the first commercially viable instant camera did not hit the market until 1948, the first instant camera was actually created by Samuel Shlafrock in 1923. 

8. The Cheeseburger

There is a good chance that at some point in your life, you had a cheeseburger. Some claim the first cheeseburger was made in 1926 by Lionel Sternberger, while others say it made its appearance earlier. 

Nevertheless, the general idea of the cheeseburger has remained the same — usually including cheddar cheese, a beef patty, lettuce, onion, pickles, mayo, and ketchup. 

9. Radio Altimeter 

For the uninitiated, the radio altimeter is a device that measures the distance between an aircraft and the ground directly below it. This technology was created by Lloyd Espenschied. He patented a collision-avoidance system for trains that used reflected radio waves in 1924, and later applied similar techniques to create a radio altimeter for airplanes. This was produced commercially by the Western Electric Company beginning in 1937. This device was revolutionary, as earlier devices could only measure the distances between the aircraft and a predefined sea level.

10. Penicillin

Penicillin is considered one of the most important discoveries of the 1920s. It was first identified by Sir Alexander Fleming, Professor of Bacteriology at St. Mary's Hospital in London, and developed as a medicine by researchers at the University of Oxford. The first patient to be successfully treated with penicillin was in 1942. Penicillin was the first medicine developed to kill bacteria.

11. The Liquid-Fueled Rocket 

The very first liquid-fueled rocket was launched by Robert Hutchings Goddard in 1926, in the United States. It was developed as a part of the research for the first World War liquid-fuel rockets. Goddard had a total of 214 patents in rocketry. This 1920s invention has gone on to shape astronautics. 

For more on the great inventions of the past century be sure to stop by here.