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A comment on Ask HN: What scientific phenomenon do you wish someone would explain better?. Parent comment

Re:Ask HN: What scientific phenomenon do you wish someone wo... by na85 on Sunday April 26, 2020 @07:04PM (#22991118)
>The top of a wing is curved, making it longer than the bottom of the wing. This means that air takes longer to go over it, meaning it has to spread out further to go the same distance as the air under the wing. As a result, the air going over the top of the wing is less dense, (aka lower pressure). The wing tries to equalize the pressure by moving in the direction of the low pressure, which is Up. We call this Lift.

100% completely false.

Imagine you have two particles of air, and they are immediately adjacent to each other. Suppose now that one goes above the wing, and one goes underneath. In your example, the particle going upward goes further in the same amount of time.

But ask yourself this: Why do the particles of air have to arrive at the same time? What mechanism from physics requires that they meet up again at the far end of the wing?

Then ask yourself this: If what you described is true, then how do aircraft fly upside down?

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Re:Ask HN: What scientific phenomenon do you wish someone wo... by Biganon on Sunday April 26, 2020 @07:32PM (#22991292)
For years I thought I was crazy or stupid, whenever I heard this story of "air has to go faster" I was like "but how does air know?? It's not like it has a Google maps plan telling it it needs to reach the other end of the wing at a precise time!"

By chance, in the last few years I've started reading more and more comments debunking this absurd explanation. Not that I understand perfectly now, but at least I know I'm not crazy.

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Re:Ask HN: What scientific phenomenon do you wish someone wo... by na85 on Sunday April 26, 2020 @07:37PM (#22991325)
In fact that "air has to go faster" silliness only works if you completely neglect air friction entirely, because then the air can be said to part around the wing like butter around a hot knife.

But of course anyone who's seen snow billowing off the back of a car knows that air doesn't just close up behind the object like a ziplock bag: it's messy and turbulent and gets all over your windows while you're tailgating.

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