Pluto is the Ninth Planet
Originally taught: 1930-2006
Disproven: 2006
Pluto was reclassified as a 'dwarf planet' by the International Astronomical Union in 2006.
AstronomySearch by Graduation Year
Find out what facts have been disproven since you graduated
All Disproven Facts
Humans Only Use 10% of Their Brain
Originally taught: 1900-2010
Disproven: 2010
Brain imaging studies show that we use virtually every part of the brain, and most of the brain is active almost all the time.
NeuroscienceColumbus Discovered America
Originally taught: 1492-Present
Disproven: 1960
Indigenous peoples lived in the Americas for thousands of years before Columbus, and Norse explorers reached North America around 1000 AD.
HistoryDinosaurs Are Extinct
Originally taught: 1840-1990
Disproven: 1990
Birds are descendants of theropod dinosaurs, meaning dinosaurs are not entirely extinct.
PaleontologyDinosaurs Looked Like Big Lizards
Originally taught: 1800-1996
Disproven: 1996
Many dinosaurs had feathers and were colorful, as evidenced by fossils like Sinosauropteryx.
PaleontologyBrontosaurus Is Not a Dinosaur
Originally taught: 1903-2015
Disproven: 2015
A 2015 study reinstated Brontosaurus as a distinct genus based on morphological differences.
PaleontologyGeorge Washington Had Wooden Teeth
Originally taught: 1780-Present
Disproven: 1900
His dentures were made from ivory, gold, lead, and human or animal teeth; the wood myth arose from stained ivory.
HistorySalem Witches Were Burned at the Stake
Originally taught: 1692-Present
Disproven: 1900
Nineteen were hanged and one was crushed; no one was burned, following English law.
HistoryThere Are Three States of Matter
Originally taught: Ancient-1879
Disproven: 1879
Plasma was discovered as the fourth state of matter by Sir William Crookes in 1879.
PhysicsToilets Flush Opposite in the Southern Hemisphere
Originally taught: 1900-1960
Disproven: 1960
The Coriolis effect is too weak to influence toilet flushing; direction is determined by bowl design.
PhysicsNeanderthals Were Less Intelligent Than Humans
Originally taught: 1850-2014
Disproven: 2014
Research shows Neanderthals were as intelligent, with evidence of art, tools, and jewelry.
AnthropologyPeople Are Left-Brained or Right-Brained
Originally taught: 1960-2013
Disproven: 2013
A 2013 University of Utah study found no evidence for hemispheric dominance in personality.
NeuroscienceBlood Is Blue When Deoxygenated
Originally taught: Unknown-Present
Disproven: 2000
Blood is always red; veins appear blue due to how light penetrates the skin.
BiologyNapoleon Was Short
Originally taught: 1803-Present
Disproven: 1900
He was about 5 feet 7 inches, average for his time; the myth originated from British propaganda.
HistoryHumans Have Five Senses
Originally taught: Ancient-1900
Disproven: 1900
There are additional senses like proprioception, balance, and thermoception.
BiologyThe Tongue Has a Taste Map
Originally taught: 1901-1974
Disproven: 1974
All tastes can be detected across the entire tongue, as shown by Virginia Collins' study.
BiologySwallowed Gum Takes 7 Years to Digest
Originally taught: Unknown-2007
Disproven: 2007
Gum passes through the digestive system in about a week, like other indigestible items.
HealthHair and Nails Grow After Death
Originally taught: Unknown-1900
Disproven: 1900
They appear longer due to skin dehydration and shrinkage, not growth.
BiologyThomas Edison Invented the Lightbulb
Originally taught: 1880-2007
Disproven: 2007
He improved existing designs; Humphry Davy created the first in 1802, Joseph Swan in 1860.
HistoryI Before E Except After C
Originally taught: 1866-1900
Disproven: 1900
There are numerous exceptions like 'weird' and 'science,' making the rule unreliable.
LanguageGreat Wall Visible from Space
Originally taught: 1932-2003
Disproven: 2003
It is not visible without magnification; astronauts confirmed this in 2003.
GeographyPaper Can't Be Folded More Than 7 Times
Originally taught: Unknown-2002
Disproven: 2002
Britney Gallivan folded paper 12 times in 2002 using a large sheet.
MathematicsBats Are Blind
Originally taught: Ancient-1900
Disproven: 1900
All bats have vision; some have excellent eyesight for low light.
BiologyBulls Are Enraged by Red
Originally taught: Unknown-2007
Disproven: 2007
Bulls are colorblind to red and react to movement; confirmed by MythBusters in 2007.
BiologyGoing Out with Wet Hair Causes Colds
Originally taught: Unknown-1990
Disproven: 1990
Colds are caused by viruses, not temperature or wet hair.
HealthCracking Knuckles Causes Arthritis
Originally taught: Unknown-2011
Disproven: 2011
A 2011 study found no link between knuckle cracking and arthritis.
HealthThe 5-Second Rule for Dropped Food
Originally taught: Unknown-2016
Disproven: 2016
Bacteria transfer instantly; a 2016 Rutgers study debunked it.
HealthThe Food Pyramid is the Best Nutrition Guide
Originally taught: 1992-2011
Disproven: 2011
Replaced by MyPlate in 2011 for a simpler, more accurate representation.
NutritionScientists Predicted Global Cooling in the 1970s
Originally taught: 1970-Present
Disproven: 2008
A 2008 study showed it was a myth; most papers predicted warming.
EnvironmentJunk DNA Has No Function
Originally taught: 1972-2012
Disproven: 2012
The ENCODE project in 2012 revealed functions in regulatory roles.
GeneticsThere Is a Dark Side of the Moon
Originally taught: Ancient-1959
Disproven: 1959
The Luna 3 spacecraft in 1959 photographed the far side, showing it receives sunlight.
AstronomySugar Makes Kids Hyperactive
Originally taught: 1970-1994
Disproven: 1994
A 1994 study in the Journal of Abnormal Child Psychology found no link; it's a myth.
HealthGoldfish Have Short Memory
Originally taught: 1950s-Present
Disproven: 2003
Experiments have shown that goldfish can remember tasks for months, debunking the myth of their short memory.
BiologyShaving Makes Hair Thicker
Originally taught: Ancient-Present
Disproven: 1928
A clinical study in 1928 showed that shaving does not affect hair growth rate, thickness, or color; it only appears thicker due to blunt tips.
BiologyCarrots Improve Vision
Originally taught: 1940s-Present
Disproven: 1940
This myth originated from WWII British propaganda to hide radar technology; while vitamin A in carrots aids eye health, it doesn't enhance vision beyond normal levels.
NutritionLightning Never Strikes Twice
Originally taught: Ancient-Present
Disproven: 1752
Lightning can and does strike the same location multiple times, as observed with tall structures like the Empire State Building being hit dozens of times a year.
MeteorologyReading in Dim Light Ruins Eyes
Originally taught: 1900s-Present
Disproven: 1950
It may cause temporary eye strain, but no permanent damage; ophthalmologists confirm it doesn't affect long-term vision.
HealthEinstein Failed Math
Originally taught: 1920s-Present
Disproven: 1935
Einstein excelled in math; the myth likely arose from him failing a university entrance exam at 16, but he was advanced for his age.
HistoryVikings Wore Horned Helmets
Originally taught: 1800s-Present
Disproven: 1890
No archaeological evidence supports this; the image comes from 19th-century opera costumes and romanticized art.
HistoryDogs and Cats Are Colorblind
Originally taught: 1900s-Present
Disproven: 1989
They see in shades of blue and green; their color vision is limited but not absent, as shown by behavioral studies.
BiologyLemmings Commit Mass Suicide
Originally taught: 1950s-Present
Disproven: 1958
This myth was staged in a 1958 Disney documentary; lemmings may drown accidentally but don't intentionally suicide.
BiologySharks Don't Get Cancer
Originally taught: 1990s-Present
Disproven: 2013
Tumors have been found in multiple shark species, debunking the claim used to promote shark cartilage supplements.
BiologyOstriches Bury Heads in Sand
Originally taught: Ancient-Present
Disproven: 1940
They lower their heads to the ground to blend in or flip eggs; the myth comes from Pliny the Elder.
BiologyWarts from Toads
Originally taught: Ancient-Present
Disproven: 1920
Warts are caused by human papillomavirus, not amphibians; the bumpy skin of toads led to the association.
HealthSharks Smell Blood Miles Away
Originally taught: 1970s-Present
Disproven: 2000
They can detect blood at 1 part per million, but typically from hundreds of meters, not miles, depending on currents.
BiologyGiraffes Sleep 30 Minutes a Day
Originally taught: 1900s-Present
Disproven: 2010
Studies show they sleep around 4-5 hours in short bursts, similar to other large herbivores.
BiologySharks Die If They Stop Swimming
Originally taught: 1900s-Present
Disproven: 1960
Many sharks can pump water over gills while stationary; only some species need constant motion.
BiologyPoinsettias Are Deadly Poisonous
Originally taught: 1910s-Present
Disproven: 1971
They may cause mild irritation but are not lethal; a study showed no toxicity even in large amounts.
BotanyHIV From Sex With Monkeys
Originally taught: 1980s-Present
Disproven: 1990
It likely transferred through bushmeat hunting and blood contact, not sexual activity.
HealthHumans Evolved From Chimpanzees
Originally taught: 1850s-Present
Disproven: 1871
Both share a common ancestor from 6-8 million years ago; chimps and humans evolved separately.
EvolutionPenny From Skyscraper Kills
Originally taught: 1930s-Present
Disproven: 2000
Terminal velocity is too low (about 50 mph) to be lethal; it might sting but not kill.
PhysicsMoon Gravity Causes Tides
Originally taught: Ancient-Present
Disproven: 1687
Tides result from gravitational differences across Earth due to moon and sun; it's a differential force.
AstronomyEarth Is Perfect Sphere
Originally taught: Ancient-1700s
Disproven: 1738
It's an oblate spheroid, flattened at poles and bulging at equator due to rotation.
GeographyMount Everest Tallest Mountain
Originally taught: 1850s-Present
Disproven: 1990
From base to peak, Mauna Kea is taller (over 33,000 ft vs. Everest's 29,000 ft), though Everest is highest above sea level.
GeographyWater Conducts Electricity
Originally taught: 1900s-Present
Disproven: 1800
Pure water is a poor conductor; impurities like salts make it conductive.
ChemistryGlobal Warming Pause
Originally taught: 2000s-2010s
Disproven: 2015
Surface temperatures seemed stable, but oceans absorbed most heat; adjusted data shows no pause.
EnvironmentSahara Largest Desert
Originally taught: Ancient-Present
Disproven: 1900
Antarctica is larger (5.4 million sq mi vs. 3.6 million) and fits the desert definition of low precipitation.
GeographyDiamonds From Coal
Originally taught: 1800s-Present
Disproven: 1950
Diamonds form from carbon deep in the mantle, predating most coal; coal rarely subducts deep enough.
GeologyMiddle Ages Flat Earth
Originally taught: 1800s-Present
Disproven: 1920
Most scholars since ancient Greeks knew it was round; the myth was popularized in 19th-century writings.
HistorySummer Closer to Sun
Originally taught: Ancient-Present
Disproven: 1543
Seasons are due to Earth's tilt; Northern summer happens when farther from sun but tilted toward it.
AstronomyBatteries in Fridge Last Longer
Originally taught: 1950s-Present
Disproven: 2000
Cold can cause condensation and damage; room temperature is best for modern batteries.
TechnologyHumans and Dinosaurs Coexisted
Originally taught: 1800s-Present
Disproven: 1840
Dinosaurs went extinct 66 million years ago; humans appeared about 300,000 years ago.
PaleontologyEating Turkey Makes You Sleepy
Originally taught: 1970s-Present
Disproven: 1980
Tryptophan levels are similar to other meats; post-meal sleepiness is from overeating carbs and fats.
NutritionFlu Shots Give You Flu
Originally taught: 1930s-Present
Disproven: 1940
Vaccines use inactivated virus or proteins; mild symptoms are immune response, not infection.
HealthBig Bang Was an Explosion
Originally taught: 1940s-Present
Disproven: 1950
It was rapid expansion of space itself, not an explosion in preexisting space.
AstronomyMilk Builds Strong Bones
Originally taught: 1920s-Present
Disproven: 2010
Studies show no reduction in fracture risk; high dairy may increase bone loss due to acidity.
NutritionNo Gravity in Space
Originally taught: 1950s-Present
Disproven: 1687
Gravity is everywhere; astronauts experience microgravity in orbit, falling around Earth.
Physics