Hacker News Reader

Comment by _dain_ | Hacker News Reader

This feels like a motte/bailey tactic. I remember clearly being taught the equal-transit-time theory as a kid, and it was taught as actual fact, not a simplification. I was uneasy with it but couldn't vocalize why (it didn't occur to me to ask why planes can fly upside down).

If it is meant as a simplification, many HS teachers have not gotten the memo.

View on HN

Substantially everything taught as fact in HS science is a simplification or a poorer approximation of a better answer though, isn't it?

In elementary school I remember hearing the planets move in CIRCLES in THE SAME PLANE around the Sun.

In an atom, electrons would also move around the nucleus like a mini-solar system.

For seven and eight years old children, it's a fair simplification, I guess.

If I taught elementary school I would explain that planets move nearly in circles and often in the same plane.

It's not that elementary school children can only handle absolutes.

Ocean waves work like this: water molecules are piled up in humps, and all the molecules slide across the ocean, while the water underneath the humps does not move. If you poured some dye into the waves, the water-humps would carry it along.

Sound works like this: vibrating objects put energy into air molecules, then the molecules zoom all the way to your ears at the speed of sound. They put the sound vibrations into your eardrum. Then they zoom all the way back to the vibrating object. Then repeat.

Uh, that's all wrong. Not oversimplified. Just wrong. (Airfoil explanations are similarly wrong. Not just oversimplified.)

> I was uneasy with it but couldn't vocalize why

I can vocalize why I am uneasy with it: why does the separated airflow need to meet back at the same point? How does the top-air know it needs to hurry to keep up with the bottom-air?

I mean, there might be a reason for that, but I would rather someone explained that instead of waving their hands. :-)

Reply on news.ycombinator.com