Science
37 myths in Science
School science packed a lot of confidence into tidy diagrams: nine planets, five senses, blue blood in veins, a tongue map you could color in. Some of those lessons were honest simplifications that aged poorly; others were folklore that somehow made the textbook. This hub collects science claims that showed up in worksheets and lectures, then got revised when the evidence caught up.
What you were taught
The Big Bang theory explains where the universe came from
What we know now
The Big Bang theory describes how the universe expanded from a very hot, dense state, but it does not explain what existed before the Big Bang or where the initial singularity came from. It describes the evolution of the universe, not its ultimate origin.
Updated understanding emerged around 2020
What you were taught
Daddy Longlegs are the most venomous spiders but can't bite humans
What we know now
This is a persistent myth. "Daddy longlegs" can refer to harvestmen or cellar spiders, and neither supports the claim that they are the most venomous spiders on Earth but somehow cannot bite humans. The story is folklore, not settled zoology.
Updated understanding emerged around 2020
What you were taught
Most of the oxygen we breathe comes from trees
What we know now
While trees produce oxygen, the vast majority of the Earth's oxygen (estimated between 50-80%) is produced by marine phytoplankton through photosynthesis. This fact highlights the critical role of oceans in sustaining life on Earth.
Updated understanding emerged around 2020
What you were taught
Brontosaurus is a real dinosaur species
What we know now
Brontosaurus was long treated as a misidentified Apatosaurus, but a 2015 reassessment argued that Brontosaurus is distinct enough to be recognized again as its own genus. The real myth is that the name was permanently invalidated.
Updated understanding emerged around 2015
What you were taught
A penny dropped from a skyscraper can kill someone below
What we know now
A falling penny reaches terminal velocity quickly and is too light and flat to penetrate the skull. It might sting, but physics shows it is not a lethal projectile from a tall building.
Updated understanding emerged around 2012
What you were taught
Dinosaurs shed their skin all at once like snakes
What we know now
Contrary to previous beliefs, scientists have discovered proof that dinosaurs shed their skin a little at a time, comparable to human dandruff, not all at once like snakes or lizards.
Updated understanding emerged around 2010
What you were taught
Girls are naturally not as good at math as boys
What we know now
A 2011 study by the University of Wisconsin-Madison, using global data, disproved the notion that there is a natural male/female gap in mathematical achievement. The study concluded that differences in math performance are due to social and cultural circumstances, not biology.
Updated understanding emerged around 2010
What you were taught
IQ tests are the definitive measure of intelligence
What we know now
A 2012 study by the University of Ontario debunked the theory that IQ tests are the sole definitive measure of a person's intelligence. Researchers found that many factors impact the results of such tests, and a single, standardized test yields misleading and imperfect results.
Updated understanding emerged around 2010
What you were taught
Mars was a dry, barren planet
What we know now
For many years, Mars was thought to be a dry, barren planet. However, in 2011, scientists discovered evidence of saltwater on the surface of Mars, indicating the possibility of simple organisms.
Updated understanding emerged around 2010
What you were taught
The marshmallow test proved willpower predicts success
What we know now
The famous marshmallow test was conducted by Walter Mischel in the 1970s, but subsequent research has shown that willpower is not a reliable predictor of success. Instead, success is more closely tied to factors like intelligence, social skills, and perseverance.
Updated understanding emerged around 2010
What you were taught
Planet X (Planet 9) exists and explains gravitational pull
What we know now
While scientists observed a strange gravitational pull in a nearby solar system, the theory that it was caused by a mystery planet (Planet X or Planet 9) was challenged in 2019. Other scientists proved that a large amount of debris could just as easily explain that pull.
Updated understanding emerged around 2010
What you were taught
Natural blond and red hair are going extinct in the global population
What we know now
Hair color is controlled by recessive genes that can persist hidden in carriers for generations. Population genetics does not support claims that blond or red hair is disappearing from humanity.
Updated understanding emerged around 2007
What you were taught
All the cells in the human body are replaced every seven years
What we know now
Cell turnover varies widely by tissue. Some cells renew in days, while neurons and lens cells can last a lifetime. The seven-year figure is a rough average, not a universal replacement schedule.
Updated understanding emerged around 2005
What you were taught
A goldfish's memory span is only 3 seconds
What we know now
Research shows goldfish can remember feeding routines, navigate mazes, and retain information for weeks or months. The three-second claim is a popular myth, not supported by animal behavior studies.
Updated understanding emerged around 2003
What you were taught
Dinosaurs were cold-blooded and sluggish
What we know now
The old schoolbook picture of dinosaurs as slow, cold-blooded lizards is outdated. Dinosaurs were generally active animals, many lineages show signs of elevated metabolism or warm-bloodedness, and birds (living dinosaurs) are warm-blooded. Metabolism likely varied across groups, and details are still researched.
Updated understanding emerged around 2000
What you were taught
Dinosaurs died only from a volcano
What we know now
While volcanic activity was present, the prevailing scientific consensus is that the extinction of non-avian dinosaurs was primarily caused by the impact of a large asteroid (Chicxulub impactor) about 66 million years ago, which led to widespread environmental devastation.
Updated understanding emerged around 2000
What you were taught
The Great Wall of China is visible from space
What we know now
This popular myth, often taught in schools, overstates the case. The wall is not visible from the Moon, and from Earth orbit it is usually difficult or impossible to see with the naked eye because it is narrow and blends with the land. High-contrast features like cities and highways are easier to spot.
Updated understanding emerged around 2000
What you were taught
Humans swallow an average of eight spiders per year in their sleep
What we know now
This claim is an urban legend with no evidence behind it. Spiders generally avoid sleeping humans, and there is no reason to believe people routinely swallow spiders while asleep.
Updated understanding emerged around 1993
What you were taught
Humans have five senses
What we know now
While the traditional five senses (sight, hearing, touch, taste, smell) are fundamental, modern science recognizes many more, including proprioception (sense of body position), nociception (pain), thermoception (temperature), and equilibrioception (balance), among others.
Updated understanding emerged around 1990
What you were taught
Viruses are alive just like tiny organisms
What we know now
Viruses lack independent metabolism and cannot replicate outside a host cell. Most virologists treat them as non-living infectious particles that hijack cellular machinery rather than as fully alive organisms.
Updated understanding emerged around 1990
What you were taught
An ice age is imminent due to global cooling
What we know now
In the 1970s, some media outlets speculated that the Earth might be entering a new ice age due to short-term cooling trends and aerosol emissions. However, climate science has since evolved, and the overwhelming consensus now shows that human-induced global warming—primarily caused by greenhouse gas emissions—is the dominant trend. Evidence from NASA and the IPCC confirms that the current warming rate is unprecedented over millennia and directly linked to human activity.
Updated understanding emerged around 1988
What you were taught
Lightning never strikes the same place twice
What we know now
Lightning often hits the same tall or conductive structures repeatedly. Tall buildings and towers can be struck many times in a single storm because electrical discharge is not limited to one strike per location.
Updated understanding emerged around 1985
What you were taught
Each gene encodes exactly one protein
What we know now
Genes can produce multiple proteins through alternative splicing and regulation, and many genes do not code for proteins at all. The one-gene-one-protein rule was an early simplification that modern genetics has outgrown.
Updated understanding emerged around 1985
What you were taught
Blood in your veins is blue
What we know now
Human blood is always red. Deoxygenated blood is dark red, not blue. Veins can look blue through skin because of how light scatters in tissue, not because the blood itself changes color.
Updated understanding emerged around 1980
What you were taught
Continental drift is still a controversial theory
What we know now
Continental drift was initially proposed by Alfred Wegener in the early 20th century but lacked a mechanism for movement. By the 1960s, plate tectonics emerged as the accepted explanation, supported by seafloor spreading and magnetic striping evidence. By the 1980s, it became widely accepted in the scientific community as foundational geoscience.
Updated understanding emerged around 1976
What you were taught
Summer is warmer because Earth is closer to the Sun
What we know now
Seasons are caused by Earth's axial tilt, not distance to the Sun. When it is summer in the Northern Hemisphere, that hemisphere is tilted toward the Sun, making sunlight more direct and days longer.
Updated understanding emerged around 1975
What you were taught
The tongue has distinct regions only for sweet, salty, sour, and bitter tastes
What we know now
The classic tongue taste map is a myth based on a mistranslation of old research. Taste receptors for sweet, salty, sour, bitter, and umami are distributed across the tongue and mouth.
Updated understanding emerged around 1974
What you were taught
Heavier objects fall faster than lighter objects in free fall
What we know now
Galileo and later experiments showed that in a vacuum all objects accelerate equally under gravity. In air, lighter objects may fall more slowly because of drag, not because weight alone determines acceleration.
Updated understanding emerged around 1971
What you were taught
Pure water conducts electricity strongly
What we know now
Distilled water is a poor conductor. Everyday water conducts because dissolved salts and minerals carry electrical current, not because pure H2O itself is conductive.
Updated understanding emerged around 1970