The Roaring Twenties didn't just roar with jazz, flappers, and speakeasies—it hummed with the sound of innovation. As America emerged from World War I, the decade ushered in unprecedented economic prosperity, with the nation's total wealth more than doubling between 1920 and 1929. For the first time, more Americans lived in cities than on farms, creating new demands for modern conveniences and life-saving medical breakthroughs.
This was the decade when women gained the right to vote with the 19th Amendment in 1920, and technology began transforming everyday life. By decade's end, radios sat in more than 12 million American households, connecting the country like never before. The 1920s gave us inventions that would become household staples—from the Band-Aid that patched up scraped knees to the pop-up toaster that simplified breakfast.
Medical innovations saved lives, with insulin giving hope to diabetics and the iron lung helping polio patients breathe. Meanwhile, practical inventions like Q-tips, Scotch tape, and frozen food made daily life a little easier. Some inventions, like the polygraph, sparked controversy that continues today. Others, like sliced bread—which arrived in 1928—became the benchmark against which all future innovations would be measured.
To find the most interesting inventions of the 1920s, Stacker scoured news reports and patents. Click through to discover the brilliant innovations from this transformative decade.
1920: Band-Aid
Earle and Josephine Dickson created the first adhesive bandage in 1920. The two took the idea to Johnson & Johnson, where Earle was a cotton buyer. Their invention became trademarked as Band-Aid. The company now makes a liquid sealant, and some come pre-treated with antibiotics.
1921: Polygraph
John Larson, a police officer in Berkeley, California, created the first polygraph machine in 1921. It was designed to detect sudden changes in blood pressure with the thought that if someone was nervous, it might be a sign they're lying. The machines have been controversial, and most courts don't allow results as evidence. In 2018, the U.S. Department of Homeland Security funded an artificial intelligence technology called AVATAR that assesses truthfulness by subtle changes in eye movements, voice, or body shifts.
1922: Insulin
On Jan. 11, 1922, Dr. Frederick Banting administered the first treatment of insulin for diabetes, which he developed along with medical student Charles Best. Before insulin treatment was available, most people with type 1 diabetes didn't live very long. Modern-day insulin still can't be administered in pill form, but people can give themselves daily shots or wear a pump.
1923: Q-tips
After Leo Gerstenzang saw his wife adding cotton to toothpicks, he created cotton swabs and founded the Q-tips Company. Their original name was "Baby Gays," but Gerstenzang changed the name to Q-tips—the Q stands for quality.
1924: Frozen food
People have been freezing food for millennia, but Clarence Birdseye is often credited with inventing the modern way of quick-freezing food. Birdseye invented the method after realizing that ice would form on food if it was frozen too slowly. When defrosted, the crystals would melt and affect the quality and taste of the food.
1925: Mechanical television
In 1925, inventor John Logie Baird showed off a mechanical device that projected the shadow of a doll on the other side of the room. A year later, he would unveil the mechanical TV, the precursor to the modern electric television that was invented by Philo Farnsworth in 1927.
1926: Liquid rocket fuel
On March 16, 1926, Robert Hutchings Goddard used liquid rocket fuel in a rocket he built and tested. Goddard proposed the idea of a rocket reaching the moon back in 1920. His research and inventions directly contributed to the existence of modern space flight.
1927: Iron lung
Philip Drinker and Louis Agassiz Shaw Jr. invented a tank respirator known as the iron lung to help patients with polio. The machine acts as a mechanical diaphragm, forcing air into the lungs of people who could no longer swallow or breathe on their own. Most patients only needed treatment for a few weeks, but some required lifelong assistance.
1928: Sliced bread
Richard O. Rohwedder filed his patent for a bread-slicing machine in 1928. That same year, he sold his invention to the Chillicothe Baking Company in Missouri, which became "The Home of Sliced Bread." Also in 1928, Scottish physician and scientist Alexander Fleming discovered penicillin; he noticed that something in mold had inhibited bacterial growth. In June 1929, he published his findings in the British Journal of Experimental Pathology.
1929: Cardiac catheterization
Werner Forssmann performed the first heart catheterization on himself in 1929, laying the groundwork for modern cardiology. Catheterization helps doctors get to a patient's heart through more accessible veins. Inserting pacemakers, repairing heart valves, and unblocking blood vessels are all procedures that use the method.
