A^2 + B^2 = C^2 is known as the Pythagorean theorem. This theorem explains the proportionality of the 3 sides of a right triangle (a triangle with 1 corner angle = 90 degrees). If you know the length of 2 sides (in his example, the wall beams) you can find out the length of the third (in his example, this would be the supporting strut spanning the beams that meet at a 90 degree angle). If their example is explaining a beam that spans the room from 1 corner to the other, you still use this formula as a rectangle is 2 right triangles that meet along their hypotenuse (the longest leg of a right triangle, or the length you are solving for in this problem). The 2 known sides are the length/width of the room, and you solve for the 3rd side, your diagonal beam
The reason they drill it in to the extent that they do is so that you have a foundational understanding of the underlying math on which to build new knowledge. If you show up in calc 1 in college without remembering even the basic concepts you were previously taught in things like trig…that can really bite you in the ass. My teacher LOVED pulling out classic substitutions for Secant, Cosecant, and cotangent (No, i didnt outright remember them from Trig, but I had seen them, and that made refreshing much easier). Also these concepts then form the basis of many other fields such as physics (electricity/magnetism, kinetic motion, optics, etc.), chemistry (quantum, MO theory, and things relating to the physics side of why chemistry occurs), and many of the graphing concepts used in engineering/stem only make sense if you have the foundational understanding of what integration/derivation are. Those stem from understanding how to graph complex functions by hand (like we did in trig) so that when you are doing it later with assistance, you still GRASP what is going on.
Yes its not perfect, and yes for people who never need that later in life it can suck. However, I would make the argument it is better to have more of your population educated to a higher standard than what is needed in daily life, than to only give that to those who are aware enough at a young age to actively seek said education
There will be those that do and dont get the “nitty gritty” of the theory side of the math. Those people sometimes become math majors. Normal people (joking, dont be mad math majors), need more than simply the theory side of the math and actually need to see/perform the application side of things. I never once “understood” the lesson in math class when we go over the equations with variables only. I only truly began to learn the material and be able to use it once we got to the example problems. We would do multiple in class and then I would understand how to literally go through the problem and perform the math that was expected of me on the homework, and subsequently the test. There is tons of stuff i know how to use in math, but by no means understand WHY it came to be, or HOW its works for the realm of mathematics. I wanna know how this math can help me solve real life problems, problems I will face in industry, or even just a cool way to apply math in the real world. Not how it will be used in research to find new types of math we wont be able to apply for 70 years.
It was pretty funny being in calculus in college. I was in a class with mostly engineers who were also taking the exact same weed out courses, and nearly every day after the professor would finish showing us the theory side of the lesson, hands would shoot up and the question of, “What application does this have in real life or engineering? Like, how will I actually use this?” always got asked. So not “loving” the theory is by no means uncommon (we all wished for an application focused version of the class to exist, for people like stem students who are not into the math theory lol), but I still see the value in having it presented so that you can have a more foundational understanding instead simply going through the motions
Completely fair point, that I do not think I have the knowledge to speak on. On the Trigonometry Wikipedia page, he pops up a few times, and many trig identities are known as pythagorean identities. Perhaps its not fully trig, but was used as a basis to help discover trig? Without having the understanding pythagorus gave mathematicians regarding triangles, I would think it would be pretty hard to begin developing deeper math regarding said triangles
This is not air conditioning. Not to be the “actually” stereotype, but air condioners literally “condition” the air by removing humidity (it was actually designed for this purpose, a side effect of removing the humidity was lowering the air temperature). This is simply good ducting and natural exchange.
Good for the environment, yes! Air conditioning? No
I do not think you’re trying to say the water “does work” in the physics sense, but to clarify, the water is just a large heat sink that has a much higher heat capacity than air. You can heat the water with air (which in turn cools the air), and that water can hold MANY times the heat (per unit mass) that the air can. Water also has a higher thermal conductivity than air. Allowing it to absorb and pass heat very well. This water is in the ground which also acts as a massive heatsink.
The air passes heat to the water which then passes the heat to the ground effectively cooling your air feed. A quick look online says current soil temp in Iran 21 inches deep is 35C or 95 F. That is your lower temperature limit. It’s physically impossible to become colder than the soil temperature (in this instance, as that is your lower temperature bound for heat transfer, in reality you wont even get there, because your driving force for heat flow is gone at that point) without putting in mechanical work (which is what a compressor does in your air conditioner) to compress your cooling fluid so that it may be evaporated repeatedly to exploit the tranfer of heat into an evaporating substance
I wouldn’t call it obnoxious, it’s just pointing out that they are using terms that don’t align with what they stated. If nobody ever mentioned the difference, how can they ever learn? Not saying everyone needs “taught” but it really didn’t seem malicious like you seem to believe
This would be a great idea if you want everyone in that building to file humidity complaints every single day. Air conditioners work by using mechanical work (compressor) to exploit evaporation in order to pull heat from one location to another and exhaust it away, in turn cooling the first location (this could be air, water, etc.)
This system works by using ground temp water as a heatsink to suck heat out of the air passing over it. When it does this, it humidifies the air. In the desert…who cares? In an office building…who cares? Every single worker who is stuck there all day
If you’re saying we need better systems than the AC unit you grew up with, fear not! Many office buildings have been moving away from it (same with other large venues) they use a chilled water system. They use the best of both these systems to get WAY more performance out of way less wattage. You only need a fraction of the cooling power with a chilled water system because the water can absorb much more heat per unit mass than air and can be sized to never run during the day, but only at night when the grid is least in use
Not necessarily in your house. I’m talking about the design of the units from when you were a child (Many public buildings in the EU have AC regardless of houses not having it). AC was invented in 1901, and has come a very long way since then, and we have begun combining it with old principles to extract the best of both solutions
Combining modern refrigeration/cooling techniques with well designed passive systems that exploit material properties (Heat capacities, transfer coefficients, etc.) to their advantage is the future of HVAC. It started with CFCs and knowing we could exploit their boiling point with mechanical force to chill air beyond the outside air temperature. Who knows where science and engineering may take us next!
The second system I linked would then let the ice slow melt over the day as its way of actively chilling air passing through its exchanger.
These systems work by chilling water instead of air, which has a much higher heat capacity. Meaning, it can accept much more thermal energy per unit mass before raising its temperature by 1 kelvin. You are able to build a single, very well designed, and efficient refridgeration unit that can provide HVAC services to up to multiple high rise buildings. This reduces waste and reduces the usage of coolant/refridgerant.
This system can be reversed in the winter (heating the water instead of chilling) with geothermal heat, solar heat, or if no “green” options are readily available, natural gas direct fire heat can be extremely efficient compared to electric coil
I cant speak to other parts of the U.S. but where I am from, people would design their farm houses so that when you opened all the windows, the natural wind direction wanted to blow through your house and naturally “cool” it. Coming from a house with AC, it seemed like a shit system lol, but i guess compared to being roasted in your stuffy house, it was probably pretty nice
That is the deepest depth I could find being actively tracked on the website I ended up on. I did not wanna do a deep dive into “great” average soil temp data lol. If you have a good source of data I will gladly change my comment to include the updated numbers. I wanted to say the average soil temperature at depth is ~50-55 degrees F, but I hopped online to make sure that was not a number that I know to be true due to where I live. Good to know that its roughly 6 feet where it stabilizes
You’re completely correct, I live in an area where you’d never be trying to add humidity lol. I was also thinking in the context of why it was originally invented, which was wrong to do. I removed my comment
Yeah thats exactly the issue I ran into. I started googling stable soil temp to confirm what I thought, and rapidly ran into a lack of answers lol. Any data I could find for free on websites didn’t seem to go very deep.
In terms of depth of the Qanats, yeah I was wondering the same. Without any modern tools I’m not sure how deep they would be willing to dig out (although I bet it’s easy digging in Iran, likely sand/dry dirt vs. clay and sopping wet boggy soil).
I am at work but I’ll see if I can dredge up info on Qanat depth
Trig (lemmy.world)
Ancient Iran had air conditioning (lemmy.world)