Yeah, Earth’s round. ‘Round’ is a word that describes a variety of things, including things that are not perfectly circular or spherical.
Definitely straying into the sort of pedantry where chemists think they own the word ‘organic’.
Although English words have precise and singular meanings seems to be a misconception a lot of people are convinced about 
Okay I officially step down from my stated position
I think this thread is perfect for pedants. 
You need them indeed, but what essential in the medical-biological context means is compounds that cannot be synthesized from scratch by the organism fast enough to supply its demand, and must therefore come from the diet. Of the 21 amino acids common to all life forms, the nine amino acids humans cannot synthesize are phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, and histidine (as per Wikipedia, copy&paste). But many vitamins are essential too, and they are not equally essential for all animals: vitamin C, for instance, can be synthesized by most animals, only not by humans (and neither by hamsters nor flying foxes, I think I remember).
The first scan I had done was back when they did call it NMR.
My favorite popular misconception is that relative humidity is the percentage of water in the air relative to the most it could possibly hold. This isn’t true at all. You can absolutely have relative humidities over 100%. It is relative to the equilibrium isothermal humidity of air enclosed with pure water having a flat surface.
Air isothermally equilibrated with water having steeply convex surfaces, such as happens in clouds, is over 100% RH.
I’d say that’s an explanation of why they are essential, not what essential means.
Don’t stop on my account
And this is another instance of something everyone knows, but is in fact wrong:
Some mammals have lost the ability to synthesize vitamin C, including simians and tarsiers, which together make up one of two major primate suborders, Haplorrhini. This group includes humans. The other more primitive primates (Strepsirrhini) have the ability to make vitamin C. Synthesis does not occur in most bats nor in species in the rodent family Caviidae, that includes guinea pigs and capybaras
The ability to synthesize vitamin C has also been lost in about 96% of fish
How many more posts before someone posts a certain essay?
I think my favorite is that many religious people think the Immaculate Conception refers to Mary conceiving Jesus. No, that’s the Virgin Birth. The Immaculate Conception refers to Mary being born without sin.
Someone here described it as, you have to sterilize the bottle before you brew your beer.
Related: people who think microwaves heat food from the inside out. They do not; the microwaves excite water molecules in food from the outside in. The misconception comes from people heating microwave burritos or Hot Pockets, where the outside is merely warm and the inside is lava-hot. But that’s only because the insides are more liquid, so have more water molecules to get all hot and bothered.
Even people with Masters Degrees think that they have Master’s Degrees.
Certainly it’s wrong to imagine that microwaves cook from the very centre of the food, but they do penetrate and cook ‘from the inside’ as opposed to conventional ovens which apply heat from the outside
Isn’t that more “outdated” rather than a misconception? I don’t know exactly what the current thinking is but I do know back in the late70s to early 80s it was commonly believed ( including by experts) that you did need to have all the essential amino acids in the same meal , although perhaps not every mouthful.
I suppose its outdated, but it’s also a misconception (it wasn’t ever true).
As I understand it, the human body doesn’t have a massive capacity for storage of individual amino acids, but the circulatory and other systems provide sufficient buffering that intake can be a bit staggered, especially in a modern diet which typically is not deficient
When you do ordering from a commissary, eggs are under dairy. I suspect it’s because they don’t really go with anything else, and no one wants to make a category that just contains eggs, and dairy is the closest.
They do have the similarity in that they are one of the few edible animal products that come from animals that are still alive.
I don’t know that that’s a misconception so much as a simplification to the more typical, stable, situation. You can have greater than 100% RH, but it’s not stable, and really wants to not be that way anymore. Hence why we get clouds.
Most people would say that the water turns to ice at the freezing point, and gas at the boiling point, even though there are exceptions to this, but I wouldn’t call it a misconception either.
I recall from early childhood that the milkman delivered eggs. Maybe because dairy farms also had chickens. It could have started from that but I’m wildly speculating here.
Q: When you drop two objects of the same size & shape but different masses - say, from the Leaning Tower of Pisa - will they strike the ground at the same time?
Standard A: Yes, as Galileo demonstrated.
Correct A: No; unless this is done in a vacuum, the more massive one reaches the ground first. (And Galileo probably didn’t attempt this - it was a thought experiment.)
Only fools buy a new car. Always buy used.