What did you think the most common second guess would be? I knew the answer, but….could kidneys be your #2? heh.
It’s based on this definition of pressure: if you push on something, P > 0, if you don’t touch it, P = 0 (vacuum), if you pull on it, P < 0. Perhaps it’s not a valid definition in the strictest sense; I don’t know. At any rate, this video explains why capillary forces don’t pull the water up trees, and why it’s not pulling a vacuum. Hint: you can’t pull on a gas, but you can pull on a liquid in certain situations. And when you pull on a liquid, you are exerting a pressure equivalent to lower than a vacuum. Hence the reason, perhaps incorrectly, that some people refer to it as negative pressure.
Most people would probably think of poop and pee, and the associated organs, in some order.
Except that video does still invoke capillary action, to explain how the pores are able to maintain such a pressure difference. And it also doesn’t really explain how water can sustain such a strong tension.
You mean like coax cable? In coax cable, > 99% of the electric and magnetic fields are confined to the volume between the outer conductor and inner conductor, in whatever insulation is between outer conductor and inner conductor (air, polymer, etc.). And insulation tends to not block fields. The conductors both guide the fields and tightly confine the fields. Oliver Heaviside was a genius.
For other geometries, like the overhead power lines, the wires guide the fields, but they don’t do a good job of confining the fields; the fields are everywhere around the wires, but their intensity dies off pretty quickly with distance.
Here’s a Scientific American article that supports the video. I think the third and fourth paragraphs are most informative.
It should also be mentioned that this is all for AC power transmission. DC is different.
The Poynting vector is still alive and well for DC. Energy is still transported in the fields, just like with AC. Here is a paper published two years ago in The American Journal of Physics titled DC Power Transported by Two Infinite Parallel Wires. Here is the Introduction:
Consider a battery connected to a load resistor via two infinitely long cylindrical lossless conductors, as shown in Fig. 1. The battery has a potential difference ∆V, and the
current in the circuit is I. The two conductors have opposite charge polarities and current directions. The battery is delivering electrical power equal to I ∆V, which is absorbed and converted to heat by the resistor. However, how exactly does the electrical power travel from the battery to the resistor in the circuit? The power is shown to be transferred through the
electromagnetic field surrounding the conductors, as opposed to within them. Yet, the charges in the wires are still required, since they guide the electromagnetic field toward the resistor.
Ah, yes, I was overlooking the fact that the wires, being at different potentials, would each have a net charge.
That’s how the two Siobhans I’ve known have pronounced it.
I always though Malachi was “MAL-uh-kye”, and that’s how it’s typically pronounced in English.
In Hebrew, it’s apparently more like “mal-ach-kee”- more of a “ch” in the middle, and a short ‘i’ sound rather than a long one.
Axial tilt
yup
Means “angelic”
OK.
If Hebrew is fair play, here’s one: Is the word “Seraphim” singular or plural?
No one ever knows this, and while I don’t expect Christians to speak Hebrew, it’d be nice if they didn’t maul the words they borrow.
Well, now, let’s not just single out those poor, misguided Christians. I’m sure lots of irreligious types probably do a similar disservice.
But, as you well know, when a word is imported from another language, all bets are off on how it will end up getting rendered.
I’ve always understood “seraphim” to be the plural of “seraph” (and likewise cherub/cherubim and nephil/nephilim). And I think that’s the standard English usage, though I’m not surprised if many people are ignorant. Is that right?
I also recently learned that, in the original Polish, “pierogi” is plural, while the singular would be just “pierog”. And come to think of it, “spaghetti” sure looks like an Italian plural, while in English it’s mostly an uncountable noun. In both of those cases, the -i form has firmly embedded itself in the English language.
Oh, and I would say that some of these (like the water in trees and the power flow of wires) really aren’t “questions you should know”, since the actual answers require knowledge of physics far more sophisticated than most people can fairly be expected to learn. The answers might seem like they should be easy, but they’re not.
I just started learning Italian, and asked my teacher the same thing last month… apparently uno spaghetto IS a thing, but you would no more eat that than you would a single strand of noodle.
Is there a term for word mispronounced because they’re read through seldom heard? (“Eppy-tome, fu-Kade,” etc.)?
(The opposite of eggcorns: mangled words/phrases that are heard but not read: “for all intensive purposes” etc.)
I’m still wincing at the Curb Your Enthusiasm scene where Larry discovers his parents were non-Jews and gasps “I’m goyim!”