“‘There was some wonderful stuff about [railway trains] too in the U.S., that women’s bodies were not designed to go at 50 miles an hour. Our uteruses would fly out of our bodies as they were accelerated to that speed.’” From: www.wsj.com/articles/BL-TEB-2814
There were (and are) a ton of utterly ridiculous beliefs about what can cause harm to women, but I find this one particularly amusing in an age where millions of women fly on planes. Imagine the plane takes off, leaving all those wayward uteri spinning in the dust at the gate…
Like... they did realize any acceleration strong enough to cause your uterus to go flying out would also be strong enough to make all your other internal organs fly out too? And that men, in fact, have internal organs?
Some beliefs along these lines have been used more recently in extremely religious places like Saudi Arabia.
"If a woman drives a car, not out of pure necessity, that could have negative physiological impacts as functional and physiological medical studies show that it automatically affects the ovaries and pushes the pelvis upwards,” ...
“That is why we find those who regularly drive have children with clinical problems of varying degrees,”
The funny thing about heliocentrism is, that isn’t really the modern view either. The modern view is that there are no privileged reference frames, and heliocentrism and geocentrisms are just questions of reference frame. You can construct consistent physical models from either, and for example, you’ll probably use a geocentric model if you’re gonna launch a satellite.
But another fun one is the so-called discovery of oxygen, which is really about what’s going on with fire. Before Lavoisier, the dominant belief was that fire is the release of phlogiston. What discredited this was the discovery of materials that get heavier when burned.
Not any kind of expert, but this seems wrong to me. My understanding is that heliocentrism vs geocentrism is about the whole solar system, ie: the same frame of reference.
So if you were launching a satellite, yes, you would use earth as your reference point but that is NOT geocentrism. You would never use a geocentric model. Ever. Not these days anyway.
Again though, I'm not an expert so maybe don't take this as law
You're absolutely right. Heliocentrism and geocentrism aren't "questions of reference frame", they're cosmological models.
Nobody is using a geocentric model when they launch satellites, as any geocentric model that works with our existing observations of the universe ultimately does not have a functional understanding of gravity. And it will be remarkably difficult to keep a satellite in orbit if you disagree with the universe about how gravity works.
It’s a bit of optics, a bit of eye physiology, and a bit of how the brain works.
Optics: Your lens focuses light on a focal point. For a sharp image, this point in space should be on the retina surface. Both lens and retina are not ideal geometric objects, so directions and angles can matter.
Eye: As others said, the retina has different regions, with different amounts and types of photoreceptors. Some regions are good for a high resolution image of whatever is in focus, others are mostly used for peripheral vision.
Brain: Your brain still gets all the data, from in and out of focus photoreceptors.
Maybe it would be possible in terms of optics to focus on more than one thing at the same time. But retina composition and brain architecture are adapted to the optics which we have: One way to focus, and peripheral vision around it.
With a bit of training it should be possible to mentally focus on image parts out of physical focus; mentally focus on something in your peripheral vision. You would mentally concentrate on a physically low resolution image (lower receptor density), it might be distorted (lens optics), and your brain might not be used to use data from these receptors for this task. So the result probably still feels like “I can’t focus on that”.
Salts are absolutely necessary for ordinary nerve- and muscular function. If you’ve ever sweated a lot without eating or drinking some salt solution you would notice your muscles start twitching, vibrating and cramping. After a while you can also notice getting light headed and blurry vision.
Source: Been in situations with plenty of water but no salt, and enormous amounts of sweat. Been in the same situations with access to salt for comparison.
My father once went out to do some yard work on a hot summer day, so he made sure to take plenty of water with him. He still ended up collapsing from heat exhaustion. Only reason he didn't have to go to the hospital is because we were able to figure out what was wrong and he still had just enough energy to eat the salty snacks we gave him.
Scary fucking stuff. Keep your electrolytes up, kids.
That’s a very incorrect statement. NaCl, KCl, and MgCl2 are essential for our bodies to function appropriately. If you are working out for an hour or mowing the lawn on a hot day, you are mostly correct. You can replace the lost salt though a balanced diet. If you have sustained sweating, such as when you run a marathon or play a match of football, it can be deadly to not replace these salts.
In the vast majority of cases, people don’t need salt when they exercise. You just described a fringe case that virtually no one experiences. You high school football coach shouldn’t be giving you salt. That could be dangerous. They should be giving you water.
The coach won’t be giving them salt directly, but will always provide a sports drink which contains salts.
Ever watch any sport and a player falls over with a cramp? They have drunk too much water and not enough electrolytes.
Here’s a study from one hospital in Oslo, Norway. Norway is not considered a hot region of the world. Between 2010 and 2015 they treated 31,000 patients in the ER from a population of 135,000 for electrolyte imbalance. That’s roughly 18 patients a day. This is not some sort of fringe case.
Your eyes have a central area of the retina called the fovea which is more densely packed and has much higher acuity than the rest of your retina. That’s the area you use to pay close attention such as for reading or hunting for food. The rest of the wide field of view is more useful for detecting movement than anything else.
It’s not a flaw—it’s just the best solution for the problem of survival.
I kind of feel the opposite. There are literally invisible spores that float around the air that can spring to life in the right conditions. Until you discover the means of transport, spontaneous generation is a hypothesis that matches the facts.
A) Brain. You can train yourself to use more of your whole field, but you’ll lose that attentional “spotlight” that you normally aim at things and picks out all the detail.
If you’re ever scanning something like a thick tree, looking for something, hold your arms out and form your fingers into a square frame. Use this to further focus your attention, and scan the tree in a more methodical way by moving the finger frame. You are more likely to find the thing you are looking for this way.
Personal favorite is probably Lamarckian Inheritance. Feels like super buff people having wimpy ass babies would key people in that acquired traits weren’t being passed on.
But it’s also the textbook example of how science progresses even when the underlying model being used is incorrect. Darwin credited Lamarck for suggesting a potential mechanism for evolution. Works prior to Mendel were direct tests to Lamarckism. Mendel responded to those, and on and on it goes. Lamarck helped push the field along and that’s great.
Side note, people like to say epigenetics is a continuation of Lamarckism but I’d disagree completely. Heritability of traits is what is important here, and epigenetic marks don’t necessarily tag the genes that contribute to the traits themselves.
I don’t know if anecdotal stories are allowed here, but I grew up in Florida before the rise of A/C (no air conditioner in school until 7th year, no house with central air until I was 25. Didn’t really ever sweat until I was 20, though I can now quite normally.
My ex and husband are both from “up north” and both suffer so much more in the heat and the humidity. I suffer so much more in dry and/or cold environments.
Not completely convinced it’s biology - there is a trick to being really still in the shade that seems to sort of cool off/slow down the body. It could be behavior differences. But does seem like they are built differently, thicker and warmer, I am built more spare and cooler.
It is worth dehumidifying a building always though! It’s not good for the materials. Always fighting mildew in the houses before the central air. Everything is so much easier to maintain with the A/C.
you’re seeing elecrochemical corrosion. if you scratch aluminum in such a way that:
oxide layer is removed, and
finely divided copper is deposited, and
oxide layer can’t reform
you’ll see rapid corrosion of aluminum. normally, alumnium doesn’t corrode because of very tight oxide layer. here, oxide layer is removed first by scratching and this also deposits copper in electrical contact with aluminum. then, citrate can bind aluminum removing some of oxide layer, making aluminum more exposed and so more reactive. if you used gallium as heat transfer compound (sp?) then gallium will also disturb oxide layer and make corrosion of aluminum faster. copper elements are in this case actually protected from corrosion (by dissolving aluminum)
This seems brilliant, I wonder what will be the efficiency of such system, it seems like it could almost power itself as long as you supply it with salt water (and have the Fresh water column outlet lower than the inlet). What am I missing?
Hi, could you expand on your question (or questions) in the main post? The more clear your questions are, the easier it’ll be for someone to address them. Thanks!
It looks like you are using this one: ArctiClean 1
Which seems to be specifically made for this application and supposedly consists of “citrus and soy based solvents”. Aluminium is solved by highly acidic (like sulphuric acid) and highly basic (like sodium hydroxide) solutions. Which it really doesn’t sound like until it somehow broke down in a way it got more potent.
Was it maybe a specific thermal paste with a metal like mercury or gallium inside? Supposedly they can quickly dissolve aluminium. Of course, I don’t know what happened but maybe it was dissolved by the cleaning solution and then rapidly reacted with the Aluminium of the heat sink. If so, that would still make me wonder about the bubbling and foaming when the cleaning solution comes in contact with the left overs.
I would assume that nobody makes thermal paste out of anything terribly reactive, but… That .gif looks like something out of a NileRed video.
IIRC, gallium makes aluminum get super brittle, which might cause it to crumble like that; but the foaming makes me think that the heat sink might have managed to oxidize all the way through, and it’s aluminum oxide reacting with the cleaner.
I can’t get your images to load, but to me, a materials chemist, it definitely sounds like you’ve managed to dissolve the aluminium and copper by using an acidic solution. Presumably, the cleaning solution contains some electrolyte that should help dissolve oxides, but if the solution is corrosive enough to oxidise the aluminium and/or copper the electrolyte will make the reaction more aggressive by rapidly dissolving the protective oxide layer as it is formed, such that the aluminium/copper is further corroded.
To be fair, this is just speculation based on what I’ve read here. I could maybe give a better analysis if you let me know what solution you’ve used, and what the heat sink/paste were made of, and if I can get the pictures of the resulting product (“ash”) to load.
Copper metal "dissolves" in nitric acid (HNO3). Actually, the nitrate ion oxidizes the copper metal to copper (II) ion while itself being transformed to NO2 gas in the process; the copper (II) ion then binds to six water molecules.
Here is an AI-generated summary of this video for the people who don’t want to go to YouTube with an added ELI5:
In this video, the host, Destin, explores why cats always land on their feet, a phenomenon known as the ‘cat righting reflex’. He uses a cat named Gigi as an example and employs a high-speed camera to analyze the process.
Destin explains that when a cat falls, the first thing it does is try to figure out which way is up. It does this using the balance organ in its ear or its eyes. Then, the cat divides its body into two separate rotation axes that are tilted from each other. It pulls in its front paws, decreasing its moment of inertia at the front so it can spin quickly. At the same time, it extends its back legs, increasing its moment of inertia at the back, resulting in a smaller twist in the opposite direction. In this way, the cat compensates for the rotation and lands safely on its feet.
Destin emphasizes that cats have very flexible spines and no functioning collarbones, which contributes to their ability to perform this complex movement. He also notes that this phenomenon has baffled scientists and engineers for centuries and is studied in various fields, including physics, robotics, space satellite control, weapons development, and biomedical engineering.
The video ends with Destin playfully chasing Gigi and thanking the viewers for their attention. He encourages viewers to check out other cat videos and subscribe to his channel, Smarter Every Day.
ELI5 (Explain Like I’m 5): Imagine you’re a cat and you’re falling. You quickly figure out which way is up and down. Then, you do a clever trick. You pull your front legs close to your body and push your back legs away. This makes your front body spin fast and your back body spin slow, but in the opposite direction. It’s like when you see ice-skaters spin really fast when they pull their arms in. Once you’ve twisted enough to face downwards, you just stretch out all your legs and get ready to land on your feet. It’s a cool trick that cats can do thanks to their super flexible bodies!
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