A list of five scientific theories that were accepted and later disproved

The history of blood, as told by a hematologist

Since ancient times, blood has been seen as a semi-magical substance. Alchemists theorized it was a mixture of the four elements. Others proposed it was one of four bodily fluids whose balance dictated health. This 2019 essay by a hematologist reviews blood's reputation across cultures and centuries.

The history of germ theory, which explains that illnesses are caused by microorganisms

For centuries, the miasma theory, which held that illnesses were caused by clouds of "bad air" produced by decaying organic matter, was the accepted explanation for the spread of disease. The development of microscopes and the subsequent technology to isolate bacteria and test disease spread in mice greatly contributed to contagionists overturning miasmatists.

Why being able to disprove explanations distinguishes scientific theories from pseudoscience

Introduced by philosopher Karl Popper, falsifiability holds that a scientific theory must make predictions that could be proven inaccurate by future observations. Explanations that cannot make such predictions are not scientific theories. It is scientists' jobs to seek out data to poke holes in scientific theories, thereby potentially strengthening them if they hold up to scrutiny.

View the evolution of atomic models, with four successively overturned between 1900 and 1926

Originally thought to be indivisible spheres unique to each element, the discovery of the electron by J.J. Thomson revealed them to be made of smaller particles. Ernest Rutherford's gold foil experiment uncovered the existence of nuclei, which Niels Bohr suggested were surrounded by electrons in fixed orbits. By applying quantum mechanics, Erwin Schrödinger replaced orbits with probability clouds.

10 Shakespeare authorship theories

Although William Shakespeare is widely considered to be the authentic author of the plays attributed to him, there are still dozens of theories suggesting that others are responsible for the classic works. Was it actually his contemporary, Christopher Marlowe? Or maybe his wife, Anne Hathaway? This list explains the 10 most popular theories that have been proposed, much to more than a few Shakespeare scholars' chagrin.

Browse and explore dozens of major psychology theories

There are a ton of different psych theories—so here's a breakdown of some of the major ones according to the general psychological focus.

Benjamin Franklin once wrote a satirical essay about passing gas

The Founding Father was asked to judge a contest for the Royal Academy of Brussels, but was incensed by one of the contest's questions, which he believed was highly impractical. In response, he wrote a piece suggesting that the most essential problem for scientists to solve was the "fetid Smell" that came with passing gas.

Hippocratic doctors treated severe mental illness with the poisonous plant hellebore

Since symptoms like hallucinations were believed be due to an imbalance of black bile, yellow bile, blood, and phlegm, the treatment at the time was to bring those humors back into balance. That meant standard treatments could include bleeding a patient or using substances like hellebore to induce vomiting or diarrhea.

The theory of plate tectonics was not initially accepted until evidence became undeniable

Alfred Wegener proposed continental drift—the movement of large landmasses—in 1912 to explain why similar rock layers, plant and animal fossils, and glacial deposits were found on continents that were then unconnected. In the early 1960s, this was combined with evidence of seafloor spreading, mantle convection in Earth's interior, and earthquake and volcanic data outlining plate boundaries to produce the accepted theory.

Validation of the greenhouse effect may have been misattributed

Although Irish physicist John Tyndall showed in 1859 that water vapor and carbon dioxide could absorb and radiate infrared radiation, experiments by American scientist Eunice Foote three years earlier identified the same phenomenon for light in general. Historically overshadowed, her work was rediscovered by female historians over a century later.

The Big Bang theory explains the expanding universe and its fiery early origins

The term “Big Bang” was initially coined by a skeptic of the theory, but the name stuck despite the theory not depicting a "bang." The event took place everywhere in the universe at once, and the theory explains the abundance of hydrogen and helium in the universe.

Create anything from the elements in Little Alchemy 2

Various ancient cultures believed the most abundant substances in the world were its basic elements: earth, water, air, and fire. We may know better now, but you can make almost anything from those four things. Little Alchemy 2 is a fun, cartoonish game that allows users to create more complex items from simple substances.

Everything you know about Phineas Gage is wrong

A stray spark sent a 3.5-foot-long, 1.25-inch thick iron rod through the brain of foreman Phineas Gage in 1848, creating a scientific case that has attracted onlookers for nearly two centuries. His life reportedly soon spiraled out of control, with his behavior tending toward selfishness and chaos. Evidence of these changes is far less common, with Gage's story bloated by fabrication, scientific prejudice, and artistic license.

History's weirdest weight loss fads, fact-checked

Nothing catches popular attention more than a claim to have found a quick weight-loss technique. History shows us such claims are often unfounded. Dr. Michael Mosley explores extreme weight-loss tips from history, from tapeworms to vinegar diets.

Five potential ways to achieve time travel

While the author discounts the possibility of traveling to the past, it lays out five hypothetical modes of catapulting into the future: speed, gravity, suspended animation, wormholes, and light. Each has some scientific basis, but none are realistic for humans. Read the article to learn where they offer promise and where they fall short.

The invention of the barometer proved that air has weight

The instrument measures air pressure by creating a partial vacuum—a region with very low density—which serves as the basis for how suction works. Mercury-based barometers were used until 2007, when they were restricted due to mercury's toxicity.

Learn how your body is, scientifically, like a firework with its own slow, controlled burn.

American medical organizations rescind recognition of diagnosis cited in police custody deaths

American medical organizations have rescinded their recognition of a syndrome whose theory stemmed from discredited research. This article explores the history and implications of "excited delirium syndrome," a medical condition that can reportedly...

The scientists trying to prove Jackson Pollock's symbolism

Jackson Pollock is one of the most famous American artists in history. He is well-known for his Abstract Expressionist "drip paintings," which seemed to defy interpretation. But following the artist's posthumous bipolar diagnosis, a team of scientists attempted to prove that his symptoms, including mania and psychosis, caused Pollock to embed images under his thrown paint.

Personality tests use the Barnum effect, where vague flattery makes generic descriptions feel specific

A 1949 experiment by psychologist Bertram Forer showed that students rated identical, generic personality profiles as highly personalized. This is the same approach used in horoscopes, Myers-Briggs personality types, and fortune tellers. Even well-resourced tests like Myers-Briggs show poor test-retest reliability, with up to half of retakers getting different results.

Christians believe Jesus was resurrected, body and all

The Christian doctrine of bodily resurrection—that Jesus rose physically, not as a ghost or spirit, and that believers will do the same at the end of time—was found absurd by ancient Greeks. Plato preferred a disembodied soul escaping the body. Paul, on the other hand, staked the entire faith on it. Theologians describe the resurrected body as the same body, but as a transformed one.

The science of food allergies

Why do certain substances trigger an immune response while others don't? Listen to researchers explain the science in this five-minute video. Food allergies affect around 8% of children and 2% of adults in the US, and—unlike sensitivity or intolerance—they involve the immune system mistaking certain harmless proteins in foods as dangerous invaders, triggering a rapid and sometimes severe defense response.

Ammonium may be the sixth basic taste

Researchers have proposed various candidates for the sixth official taste, including "fat." But research published in 2023 posits that ammonium should be considered the sixth taste since they found humans can apparently detect ammonium chloride, which the scientists describe as "bitter, salty, and a little sour." Detecting ammonia could be a survival mechanism to help detect when certain foods, including seafood, are no longer safe to eat. The work hinged on experiments with human cells exposed to ammonium chloride as well as rodent research.

Ancient Greek told to kick rocks after claiming moon wasn't a deity

About 2,500 years ago, ancient Greek philosopher Anaxagoras theorized that the moon probably wasn't a goddess. This article explains how this belief led to his exile. Anaxagoras also argued the sun was just a burning rock, writing that it was the sun that illuminated the moon. According to this resource, this theory enabled Anaxagoras to accurately explain eclipses and lunar cycles.

Barbecue relies on a unique scientific equation

Barbecue's distinct flavor starts with an interaction between the heat source and food, which creates a Maillard Reaction—better known to diners as those crunchy, caramelized bits on the outside.

Limited transparency soon after Chernobyl made it a source of conspiracy theories

Some rumors about the event became perceived as more reliable than the Soviet mass media, which had omitted key information during the early days of uncertainty. The resulting theories included CIA involvement in the disaster, three-headed birds, aliens, and a weaponized earthquake.

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

Chaos theory—informally known as the butterfly effect—is the reason why weather forecasts are presented with probabilities rather than certainties.

How the most famous Ebola book, The Hot Zone, which sold 3.5 million copies and was translated into 30 languages, got aspects of the disease so wrong.

The history of many kitchen appliances involves unexpected discoveries and applications, including wartime radar turned hamster defroster and replacing an 'ice king' with heat-stealing boxes.

The concept of phantom limbs, the perception that amputated limbs are still present, dates back to a French military surgeon in the 16th century.

Clever Hans was a 1900s horse that was believed to be able to solve math equations, tell time, and read and comprehend German, until a psychology student discovered how he got his answers.

Against his wishes, Albert Einstein's brain was removed before his cremation, and the pathologist responsible stored it for decades in mason jars within a beer cooler.

Salvador Dalí believed he was his own dead brother, who had died nine months before he was born

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

Before writing 'Walden,' transcendentalist Henry David Thoreau nearly burned down his hometown with a campfire that grew out of control.

Some Pokémon have been named after real and fictional organisms, while some real-world species have been named after Pokémon, such as Chilicola charizard and Binburrum zapdos.

Pure water does not conduct electricity because this flow of energy requires the movement of charged particles, and water is a neutral molecule.

Many legends about George Washington, including his supposed wooden teeth and the story of cutting down the cherry tree, lack evidence.

See 33 images that became central to huge scandals, including a young Charles and Camilla, Michael Jackson's baby on a hotel balcony, and Hugh Grant's mugshot.

During the French Revolution, a botanist's letter asking about "dear Rhus" (poison ivy) was intercepted, leading authorities to suspect he was conspiring with the Russians.

The boiling temperature of water decreases with increasing elevation because the molecules need less energy to overcome the lower atmospheric pressure associated with thinner air.

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

Lesser-known phobias include turophobia, or the fear of cheese, and nomophobia, the fear of being without your cell phone.

The Brothers Grimm were lawyers before they were storytellers, but became interested in fairy tales as they began investigating how rules and customs had been passed down through cultures.

Volcanic activity may have triggered the Black Death by spewing gases that led to crop failures in Europe, thus forcing the import of grain ships with plague-infested fleas.

While the sun's gravity keeps the planets in orbit, their gravity also pulls on the sun, causing it and everything else in the solar system to orbit around a mutual balance point called the barycenter—the true center of the solar system.

The rivalry between Alexander Hamilton and Thomas Jefferson centered on federalism—the question of how much power the federal government should hold relative to the states.

Existentialist writer Jean-Paul Sartre coined the famous phrase 'Hell is—other people' in his play 'No Exit'