Things you learned at school that are just plain wrong

Things you learned at school that are just plain wrong

Seems many of the things we take for granted as common knowledge just aren’t true, and that many of these so-called facts were taught us at school. Here are 20 misconceptions about the world.


1. Water is blue because it reflects the sky

Water looks blue because pure water is a blue chemical. The blue color is caused by the molecular structure as well as selective absorption and scattering of the light spectrum. Impurities and other elements such as algae or plankton can create variations in the color. Water appears clear in a cup or in a shallow pond because it’s only slightly blue and there isn’t much water volume.

2. We need to drink 8 glasses of water per day

Experts agree we need eight cups of water per day. But most people assume that ‘cup’ – a unit of measurement for liquids – means ‘glass’ – which can be anywhere up to half a litre. The actual amount we need is about two litres of water a day.

But you don’t need to drink just water, since it’s present in many drinks (such as juices and tea), as well as food like fruits and vegetables.

The most correct statement? Drink when you are thirsty.

3. The Greenhouse Effect is the cause of Global Warming

The greenhouse effect often gets a bad rap because of its association with global warming, but the truth is we couldn’t live without it.

The greenhouse effect is the process by which the infrared radiation from the Sun, reflected back from the surface of the Earth, is absorbed by greenhouse gases such as water, CO2 or ozone. These gases trap the heat and regulate the climate, and are essential for our survival.

Anthropogenic Global Warming is caused by human activity, creating more greenhouse gases than necessary. Ultimately, more gases means more infrared absorption, which gradually increases Earth’s temperature beyond ‘normal.’

4. Diamonds are made of compressed coal

The idea of diamonds being formed from the metamorphosis of coal is still a widely taught concept, but a wrong one. The misconception is because diamonds and coal are both made of carbon; however, coal comes from plants and most diamonds date from well before any living plants on Earth.

The carbon that makes diamonds comes from the melting of rocks in the Earth’s upper mantle. If conditions such as the chemistry, pressure and temperature are right, carbon atoms can be formed into diamond crystals.

5. We only use 10% of our brain

A better statement is that we normally use only about 10% of our brain at a time. Different activities trigger different parts of the brain. For example, solving a mathematical problem uses different brainpower than watching a movie or cooking dinner. Over the course of a day, most people use all parts of their brain.


6. The North Star is the brightest star

If you try to find your way in the wild at night by following the brightest star, you’ll probably end up getting lost. Polaris, also known as the North Star, isn’t actually all that bright and is hardly seen from your backyard.

The brightest star in the sky (apart from the Sun) is Sirius, located in the Canis Major constellation.


7. There is no gravity in space

Watching astronauts take giant leaps for humanity on the Moon or drift in spacearound the ISS, it’s easy to assume there is no gravity in space. Actually, any object with a mass exerts a gravitational pull, and space is full of objects. The strength of this pull depends on both mass and distance.

Astronauts in orbit are still subject to the Earth’s gravity, but are weightless because they are in a constant state of free-fall as they orbit the Earth. Walking on the Moon, astronauts are no longer in free-fall and so are subject to the Moon’s gravity – about one sixth the strength of Earth.

8. The Great Wall of China is seen from space

Just shy of 9,000 km long, the Great Wall of China is the longest manmade object on Earth, and it is often said it can be seen from space, even from as far away as the Moon. But both NASA and even China’s first astronaut have said this is not possible.

The Great Wall is narrow and irregular, measuring about 10m wide on average, and can be hard to distinguish from the surrounding environment. Seeing it from the Moon would be equivalent to seeing a single hair from 2,688m away.

9. Seasons result from the elliptical nature of Earth’s orbit

If this were true, winter would be hotter than summer, since Earth is closer to the Sun in early January than in early July. And besides, the difference in distance is relatively small.

Seasons are caused by the Earth’s tilt, meaning different parts of the planet lean towards (summer) or away from (winter) the Sun at different times of year. The tilt determines the Sun’s height in the sky and the amount of sunshine a given location receives. That’s why it is winter in Australia when it’s summer in Europe.

10. Red, Yellow and Blue are the primary colors

The primary colors are actually Red, Green and Blue (RGB). More specifically, the primary colors of light are RGB and the primary colors of pigment are Cyan, Magenta and Yellow (CMY).

Unlike RGB and CMY, red, yellow and blue can’t reproduce every color in the visible spectrum – RYB has a significant bias towards browner colors!

11. Columbus discovered America

At 2 am on the 12th of October 1492, land was sighted aboard the Pinta and the discovery of America was attributed to Christopher Columbus.

But Native Americans had settled the Americas before Columbus (obviously). There is also cartographic evidence that Portuguese explorers visited the Americas and mapped the area in 1424. Additionally, Norse explorer Leif Erikson set foot on the shores of Newfoundland in Canada, long before 1492. Remains of Viking-type settlements were found in 1963, and dated to about half a century before Columbus.

12. Edison invented the light bulb

Actually, historians list up to 22 inventors of the incandescent lamp before Thomas Edison, starting with Sir Humphry Davy in the early 19th Century.

But in 1878, Edison challenged himself and his workers to produce a commercially viable and longer lasting light bulb, based on the work of inventors before him. In October 1879, by creating an extremely high vacuum inside a bulb and using a carbon filament, he filed a US patent for the first practical high-resistance lamp capable of burning for hundreds of hours.

So while he didn’t actually invent the lightbulb, he did produce the first version that was practical for everyday use.

13. Gutenberg invented the printing press

Thanks to Johannes Gutenberg, Western civilization has enjoyed books for centuries, and they are only now being replaced (slowly) by E-readers.

But Gutenberg was not the first to invent the printing press or movable type. Print technology originated in China in 593 AD, and the Chinese were printing from movable type in 1040 AD.

Gutenberg was, however, the first European to use movable type in 1439, and probably invented it independently of the Chinese. But unlike in Eastern culture, prints had a larger influence in the West, making people believe it was invented in Europe.

14. Thanksgiving is not all peaceful and humble

Thanksgiving Day in America is a time to offer thanks, and gather with family around holiday meals of turkey, stuffing, cranberry sauce and pumpkin pie. A chance to reflect on the old tradition of colonial settlers and Native Americans coming together to give thanks for a successful season’s harvest.

Because of this celebration, people often think relations between colonialists and native people were fair and friendly. But relationships between Europeans and Native Americans never had a happy ending, and the role of European disease, cultural conflict, and disputes over land and resources defined their long-term interaction. The relative peace between the Pilgrims and the Wampanoag began to deteriorate as early as the 1660s, resulting in war by 1675.

The first Thanksgiving story is but one small piece of the long and often tragic history of relations between native people and European colonists.

15. Cleopatra was Egyptian

Cleopatra is widely known for being a beautiful, charismatic queen of Egypt and the wife of Julius Caesar. But she wasn’t Egyptian.

Born in 69 BC, the last Pharaoh of ancient Egypt was actually of Macedonian Greek heritage, daughter of Ptolemy XII. She gave herself the title of Pharaoh, and was one of the few rulers to learn the Egyptian language. (Most others preferred to use Greek.)

16. Marie Antoinette said “Let them eat cake”

There is no historical evidence she said this when asked about the starving French peasantry who were suffering from a bread shortage. The phrase originally appeared in one of Rousseau’s “Confessions”, when Marie Antoinette was only 10 years old. Today, most scholars believe Rousseau coined the phrase himself, or that it can be credited to Maria-Theresa, the wife of Louis XIV.

Nevertheless, because Marie Antoinette was an unpopular queen with a reputation for being hard-hearted and disconnected from her subjects, the starving French of 1789 willingly attributed the words to her. She was executed by guillotine in 1793 after the French Revolution.

17. Napoleon was short

In reality, Napoleon was of average height for a Frenchman at that time, around 5′7″. The confusion came from a difference in measurements: both the English and the French used inches (pouces in French), but the pouce was a little longer than the British inch. After Napoleon’s death, the autopsy conducted by French and British doctors assigned a height of 5’2” in British measurements rather than French; a mistake which British propaganda was happy to propagate.

Furthermore, Napoleon was often surrounded by tall bodyguards, as was the requirement for the Imperial Guard. His soldiers also called him “Le Petit Caporal” (The Little Corporal), which was more a term of affection than a description of his height.

18. Water in the sink turns in a different way depending on the hemisphere

This statement is based on the Coriolis Effect, an apparent force caused by the Earth’s rotation that makes objects appear as though they are moving on a curved path. This effect has a major influence on large, long-lived phenomena such as hurricanes or ocean currents, but is insignificant in the case of draining water, which lasts only a few minutes and can hardly be considered large.

The only factors which affect the direction of the water as it empties down a drain are the shape of the container it’s draining from, and the way the water was introduced into the container.

19. Plants only respire at night

Another common misconception is that plantsphotosynthesize during the day and respire only at night.

Photosynthesis is a process that converts carbon dioxide (CO2) into sugar using energy from sunlight, and releases oxygen as a waste product. Cellular respiration is a process by which cells harvest the energy stored in food. Like most living beings, plants must respire in order to grow and produce energy. Cellular respiration occurs continuously in plants, not just at night.

20. Bats are blind

Despite tiny eyes and a nocturnal lifestyle, none of the 1,100 known bat species are blind, and while most rely on echolocation to hunt, some use primarily their vision. Scientists have determined bats can distinguish between different patterns and shapes, and possibly between colors too.




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