Commonly taught facts/trivia that are oversimplifications

August 30, 2021 5:54 PM

I just found out today that while Ellis Island technically closed in 1954, the concept of "Ellis Island" as an "immigrant inspection station" that most people were taught in school in the US essentially ended in 1924 due to changes in the law. But we were always taught 1954. This came as a shock to me, since several family members emigrated to the US (specifically NYC!) in 1925-1954, and I always assumed they must have passed through Ellis Island. Putting aside simple pedantry (as in this awesome thread), "common misconceptions", tall tales that our parents taught us, and of course any political/religious issues, what are some other common oversimplifications that are at least partly true but misleading?
posted by Seeking Direction to Grab Bag (21 answers total)

“Ellis Island” is also often misconceived as the entry point for pre-1890s immigrants. Before Ellis Island, most European immigrants were processed via Castle Garden, NYC... or occasionally through other East Coast ports... or very often they came more casually through Canada. And before that they just got off at the docks.
posted by Hypatia at 6:05 PM on August 30, 2021 [2 favorites]

Today (31 August) is the independence day of two of the three main regions in Malaysia: Malaya and Sabah (Sarawak was last month on the 22nd). Formation of Malaysia won't be here for another 2 weeks (16 Sept). Yet, consistently the mainstream education and the Malayan majority conflates the two. While the government has begun to officially separate the two in their communications, parts of the public service will still make mistakes like using 'National Day' for the independence day(s). But I'm giving it too much credit. I'm still being told that it's the 63rd Independence Day for Malaysia today, when the Federation of Malaysia itself is only 58 years old.

So that's my contribution.
posted by cendawanita at 6:16 PM on August 30, 2021 [4 favorites]

Taught: Napoleon was a short guy

Reality: Napoleon was 5'7", which is TALLER than most of his European contemporaries. Most recorded him as 5'2", but apparently that's "Paris Inch", which is LONGER than British inch.

5'2" converts to... 62 inches * 10.657 comes out to be 66 and some inches. So that'd make him at least 5'6" in Imperial inches.
posted by kschang at 6:38 PM on August 30, 2021 [7 favorites]

Language learning cutoff age. It's much, much easier for a young child to become completely fluent in a second or even third language, but it's more about the stresses and distractions of adulthood than about any biologically determined ability to learn languages before a certain age.
posted by amtho at 6:52 PM on August 30, 2021 [20 favorites]

I grew up being told that Dimetrodon was a dinosaur. Wasn’t until probably a few years ago that I learned Dimetrodon was a in fact a synapsid and went extinct 40 million years before dinosaurs came about. We used the term “dinosaur” pretty liberally back in the day.
posted by ejs at 6:53 PM on August 30, 2021 [10 favorites]

Oh, here's a fun one.

Taught: The ships Cristoforo Colombo aka Christopher Columbus had with him was Ni~na, Pinta, and Santa Maria

Reality: The ships are actually named la Santa Clara (Ni~na), La Pinta, and La Gallega (aka Santa Maria) (questionable?)

Columbus never really named his flagship in his own journals. He did refer to his other two ships by their nicknames. Separate historians came up with different names for his flagship. Could it have entered service as one name and renamed by Colombus? Who knows?

Source: https://www.history.com/news/christopher-columbus-ships-caravels and
https://www.wikiwand.com/en/Santa_Mar%C3%ADa_(ship)#/The_name_and_provenience_of_the_Santa_Mar%C3%ADa
posted by kschang at 7:17 PM on August 30, 2021 [6 favorites]

There's no gravity in space
posted by thelonius at 7:24 PM on August 30, 2021 [8 favorites]

Pluto is a planet
posted by AugustWest at 8:37 PM on August 30, 2021 [2 favorites]

The moon technically doesn't revolve around the Earth. It's more accurate to say that the Earth-Moon system has a barycenter which is the center of mass for these two bodies. (Imagine a grown person swinging a small child in a circle and you get the idea, the center of the rotation will probably be between the two.) In our particular case, the Earth is massive enough compared to the moon that the barycenter is still located about 1000 miles under the Earth's crust, but away from the Earth's core. By comparison, Pluto and Charon are much closer in mass, so their barycenter is located between the two planets.

The Sun is much more massive, but the aggregate mass of the planets acting on it causes the barycenter to get real wobbly, in fact the barycenter has spent most of the past 75 years outside of the surface of the sun, and will reach one of its furthest distances from the Sun's center in 2023. This is actually one of astronomers' main tools to infer the existence of planets around other stars -- watching carefully for small wobbles in their orbits caused by planets.
posted by The Pluto Gangsta at 8:58 PM on August 30, 2021 [19 favorites]

Also, while we're on an astronomy kick I'm going to steal this one from Randall Munroe:

"The reason it's hard to get to orbit isn't that space is high up. It's hard to get to orbit because you have to go so fast[...]

Space is about 100 kilometers away. That's far away—I wouldn't want to climb a ladder to get there—but it isn't that far away. If you're in Sacramento, Seattle, Canberra, Kolkata, Hyderabad, Phnom Penh, Cairo, Beijing, central Japan, central Sri Lanka, or Portland, space is closer than the sea.

Getting to space is easy. It's not, like, something you could do in your car, but it's not a huge challenge. You could get a person to space with a small sounding rocket the size of a telephone pole. The X-15 aircraft reached space just by going fast and then steering up.

But getting to space is easy. The problem is staying there.

Gravity in low Earth orbit is almost as strong as gravity on the surface. The Space Station hasn't escaped Earth's gravity at all; it's experiencing about 90% the pull that we feel on the surface.

To avoid falling back into the atmosphere, you have to go sideways really, really fast. The speed you need to stay in orbit is about 8 kilometers per second. Only a fraction of a rocket's energy is used to lift up out of the atmosphere; the vast majority of it is used to gain orbital (sideways) speed."
posted by The Pluto Gangsta at 9:13 PM on August 30, 2021 [26 favorites]

Electrons don't orbit the atomic nucleus like little planets
posted by crocomancer at 1:09 AM on August 31, 2021 [4 favorites]

One particularly pernicious one I remember from my days in a (British) school, was the idea that the Irish Potato famine caused deaths because the potatoes in Ireland were affected by disease, and Irish peasants ate only potatoes - so the peasants died of starvation. This begged the question "why didn't they just ... eat something else instead?" The full story is a whole lot more complicated - and casts the British landlords of the era in a particularly bad light.
posted by rongorongo at 1:35 AM on August 31, 2021 [9 favorites]

Basically everything you learn about how the human body in school.

We have more than five senses, and they are not discrete but overlapping, the brain does not have distinct areas that can only process certain data, your body is mostly bacteria and your digestion is totally beholden to them (and the organs of your digestion do not have neat delineations either, especially things like your colon), urine is not sterile, biological sex is far more complex than just your chromosomes and depending on your age the understanding you have of food and nutrition may range from mildly oversimplified to wildly incorrect. Your hearing is as dependent on your brain as it is any part of your ear - and involves most of your body, especially the large bones of your skull.

Also everything you learn about evolution is wrong, too. It's mostly survival of the least malfunctioning, not the fittest, with long lines of crapshots that might make you fitter to pass on your genes but might mutate you into a pseudopenis or upright hips or some other thing that makes it hard to breed, also "your" genes include those of siblings and cousins and it's often more advantageous from an evo bio perspective to have huge numbers of non breeding relations helping raise one strong clutch of chicks/litter of pups/ cluster of nephlings than breeding your own to compete against your siblings. It's also not a line creeping towards perfection, just an every spiralling mess of options without meaning or purpose beyond sprogging off the next line. Most of evolution is taught in schools (if you're lucky enough to learn it at all) as a series of just-so stories, with a linear narrative structure that suggests the sort of progression to perfection that is honestly not a reflection of how it works at all.
posted by Jilder at 1:50 AM on August 31, 2021 [24 favorites]

The “Founding Fathers” of the US were motivated primarily by a devotion to liberty in the abstract.

The Magna Carta is a significant document in history.

Caligula made his horse a senator.
posted by GenjiandProust at 2:18 AM on August 31, 2021 [2 favorites]

There are far more people who are pub-quiz confident that there are 206 bones in the human body than can actually tally them up. N=206 only works if we arbitrarily treat
fused sacrum = one bone
fused coccyx = one bone
fused innominates / pelvis = two bones, one left, one right
fused mandible = one bone
fused skull = twenty-two bones
two each of malleus incus and stapes rattling around inside the ears = six
And ignores the wide polymorphism found in normal people:
206 ignores sesamoid bones in the wrist and toes although these can be bigger than the distal phalange of your pinkie-toe.
5% of us have the 'wrong' number of thorax-lumbar vertebrae.
1:500 live births have extra digits
1:300 live births have an extra "cervical" riblet sprouting from the 7th cervical vertebra.
posted by BobTheScientist at 2:51 AM on August 31, 2021 [6 favorites]

That all longitude is based on the Greenwich observatory. I learned in a novel about hunting a sunken Spanish treasure ship that in fact the Jesuits had their own observatory, and so some (many?) maps from the era of the Spanish invasion of the Americas are based on _that_ as the zero point for longitude.
posted by TimHare at 5:12 AM on August 31, 2021 [3 favorites]

The way lift works is vastly oversimplified in high school and even in flight training. What you are taught is Bernoulli's Law, and it's wrong. Well, the law isn't wrong; its application to this problem is wrong.

How you're taught - imagine a cross section of a wing. Now imagine two particle zooming towards the front (leading edge) of the wing. Those particles hit roughly dead center on the leading edge, which requires one to go over the wing and one to go under. Due to conservation of mass, the two particles must then meet at the trailing edge of the wing at the same time. However, because of the curvature of the wing (camber), the one going over the top has a farther distance to travel. It must speed up to meet the other particle. Due to Bernoulli, the air speeding up over the top of the wing causes a drop in local pressure, which essentially sucks the wing up and keeps it aloft.

The big counterexample to this thought experiment is the flat plate theory. We know that a theoretical "flat plate" - an airfoil with no thickness and no camber - can produce lift. So, there would be no reason for conservation of mass to require air moving over the top to go faster. We also know that symmetrical airfoils work, raising the same question. We know that airfoils will work upside down (this is, in fact, how the tail of an airplane is designed). So what gives?

A better explanation ("better" here is chosen carefully because it's probably still not even "right" but true understanding is found in four+ years of study and a heaping pile of student debt, as the Zen masters said) can be found in the conservation of momentum. Due to viscous forces (friction, essentially), a fluid will be influenced by a solid object traveling through it. A fluid will "stick" to a solid (known as the zero velocity boundary layer condition), and then viscous forces in the fluid will propagate that outwards from the solid body; however, since fluids are not as tightly bound to each other as solids are (or the solid-fluid boundary), the rest of the fluid can slip against itself. What ends up happening is the solid forces the fluid to loosely conform to its shape, causing its direction to change. This is really what causes lift - a wing will basically force the air "down" and by conservation of momentum, will itself be forced back upwards. You can test this yourself - run your faucet, and then carefully hold a spoon by its very end. Gradually bring the back of the spoon in to the water stream, and it will suddenly get sucked in. Then watch how it deflects the water.

A couple of observations, then, about the phenomenon of lift. First, since we know it requires viscous forces, then we can say that there can be no lift without drag, because lift wouldn't work without friction. Second, the Bernoulli thing isn't entirely accurate, but you can map the local air pressure around an airfoil and find that it will generate low pressure on the "top" of the wing. It's especially pronounced at the point of greatest curvature of the airfoil, because the air "stuck" to the airfoil is suddenly being dragged around the bend while the nature of fluids means that the rest of the mass of air above that point is not (imagine an accordion being pulled apart). Third, all of this falls apart when the airfoil is pointed so steeply that the (relatively weak) forces holding all the atoms of air together end up being greater than the amount of force required to get our imaginary molecule all the way around this now huge bend - the air will simply break away from the wing and go do its own thing. That's known as the "critical angle of attack" and is how a wing stalls and stops producing lift.
posted by backseatpilot at 5:38 AM on August 31, 2021 [10 favorites]

This is a tough question to answer. From my experience, the older I get, the more I come to realize that nearly everything we're taught it s a gross oversimplification. I'm not joking. And most simple "facts" come loaded with qualifications and exceptions. It makes reality less, well, concrete but more interesting.
posted by jdroth at 2:04 PM on August 31, 2021 [6 favorites]

I learnt at some stage that a species is defined by whether individuals within the species are able to interbreed.

It turns out that's approximately accurate but actually a lot more complicated - I don't think I'd be able to find the post I saw on the subject because it was on Tumblr, but this New Scientist article provides an introduction.
posted by aussie_powerlifter at 1:09 AM on September 1, 2021 [1 favorite]

Snake oil salesman is a pejorative not because snake oil was inherently fake but rather they were white charlatans capitalizing on social ignorance of the real snake oil Chinese laborers taken here to build the railroads had brought with them. I guess the oil in American snakes didn’t have the same properties (unsurprising). Calling something snake oil to imply it’s fake is not accurate but to call someone knowingly passing off a fake a Snake Oil Salesman would be correct.

(This was coveted in an episode of the podcast the Maintenance Phase that I found gripping).
posted by Exceptional_Hubris at 7:33 AM on September 1, 2021 [3 favorites]

It's pretty esoteric, but the Weidermann Franz law is on my list. It's not actually wrong, but it was originally formulated and is sometimes taught to students without noting that heat transport by electrons isn't the most significant transport mechanism at most ordinary human temperatures. In typical examples you'd find in the kitchen, it gives you the wrong answer by factors of many in either direction for very conductive metals, factors of thousands for other materials. At very low temperatures, it actually works incredibly well. (With some caveats involving the way electrons interact with the surrounding environment.)
posted by eotvos at 6:25 AM on September 2, 2021 [1 favorite]