Hi everyone and welcome to the new Megathread :) For my first Mega I want to share a special interest of mine: the magnetic field and how to understand its behavior intuitively.
I’m guessing most of us have played with magnets before at some point and have felt that mysterious force pushing them apart or pulling them together, depending on how the magnets are oriented toward each other. Some of you may have also seen diagrams like this
(By Geek3 - Own work,This file was derived from: Ironfilings cylindermagnet.svg This file was derived from: Magnet compasses.svg, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=88524982)
Or done an experiment where you visualize the magnetic field lines with iron filings like this
(Public domain, Newton Henry Black, Harvey N. Davis (1913) Practical Physics, The MacMillan Co., USA, p. 242, fig. 200)
These lines represent the shape of the magnetic field. The way you can interpret them is that if you place a compass in the field, the compass will align with the field lines at that point. And the closer the lines are to each other, the stronger the magnetic field is in that area. Also, magnetic field lines always form closed loops. They appear to end at the poles of a magnet, but actually they continue on inside the magnet. They do however exit/enter the magnet at the poles.
“But Witchy,” you may ask, “why are the lines so concentrated at the poles but then they spread out so much as they travel from one pole of the magnet to the other?” Excellent question my theoretical student XD.
This is I think the key point that was a bit of a eureka moment for me when I realized it a long time ago when I was studying this stuff: the magnetic field lines “want” to be as short as possible while also “wanting” to be as far apart as possible. And when I say want, it does actually behave a little bit like a desire, as the magnetic objects in this field will experience a magnetic force tryin gthe move the object to spread out the field lines and make them shorter.
Let’s use this picture I grabbed from Wikipedia as an example:
(By Geek3 - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=10555891)
the bar magnet creates a strong magnetic field at the poles, which means lots of magnetic field lines are squeezed closely together at the poles where they enter/exit the magnet. These lines don’t want to be so tightly packed together, so they immediately start spreading out but also immediately start curving towards the opposite pole to try to keep the distance short. If you then try to bring the north pole of another bar magnet close to the north pole of this one, both have magnetic field lines coming out trying to get to their respective south poles, but now even more tightly packed together as you bring the magnets together. Since the magnetic field lines don’t want to be so close together, both magnets experience a force pushing each other away so that the magnetic field lines aren’t being pushed together so tight.
Similarly, if the south pole of one bar magnet is brought near the north pole of another, the magnetic field lines exiting the north pole of one want to go to the south pole, but the closest south pole is the south pole of the other magnet being brought close, so now the lines go through both magnets before looping back around:
(By Geek3 - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=10515628)
However, between the closest poles of the two magnets, the lines are still concentrated but will try to spread out between the poles. Since the lines want to be as short as possible and don’t want to spread out, the magnetic field exerts a force on the bar magnets pulling them together, since that would shorten the lines between the poles down to pretty much nothing.
Finally, a few of you may have been wondering what determines how much the magnetic field lines want to spread out vs shorten. These two tendencies are in opposition pretty much all the time, since spreading the lines out more requires making them longer. This is determined by something called the magnetic permeability which is a property of the materials that the field is passing through (even air or a vacuum). High permeability materials tend to concentrate the magnetic field lines more and allow them to get shorter, while low permeability materials tend to force the lines to spread out and lengthen. Examples of materials with high permeability are iron, cobalt, and other magnetic or ferromagnetic materials. Low permeability are pretty much anything that doesn’t experience force in a magnetic field, so most things.
Post thumbnail attribution: (By Omegatron - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=640068)
Anyway I hope some of you enjoyed this rant or find the information here useful. I can talk about magnets all day so feel free to hit me up if you want, though my inbox will be overflowing for the next week I’m guessing.
Enjoy the Mega!
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Just random stuff about sleep Idk
I cannot sleep anymore. Every night I lay down, close my eyes, and stare through my eyelids at the ceiling for an hour or two before taking 3mg of melatonin and finally passing out at like 4am. Please help.
Surprisingly it’s not a chronic pain thing, it’s probably Autism Brain. After midnight, my brain turns the fuck ON and into a constant monologue machine. I have spoken of this before but it is like, if my brain was that turned-on during the day I would get SO much done, think SO many thoughts and probably write a fuckton. Even when my brain is empty of thoughts, in 3am brainmode ANYTHING can start a tangent in there.
I have more than idly considered just going for it, doing 36 or 48 hour days to take advantage of this state, but I doubt my body would cope with that too well at this point. I want this state during the day.
Taking various anxiety meds did not help, an almost complete “detox” from online did not help, I am still cursed to only have my brain come on late at night and keep me awake. Idk if I’m beyond help at this point but I hate it.
I actually think I used to be like this, the After Midnight Brain, all the time, in the day. Back when I wrote fiction and shit every day. That was back in highschool though, what happened?
i have to put on jerma vods at night so i can sleep, can’t be alone with my thoughts. i can strongly relate as sleep has always been a big issue for me too. i tend to just stay up until the point of exhaustion so i can be sure that going to sleep won’t be a Whole Thing (not recommending this). i have found that weed helps me with it too. i hope you can overcome this phase and find something that works for you
Sleebi weed
I really need to get down to the dudeweed store soon!!
Thenk u
This is pretty much how it is for me, taking it like 15 minutes~ before laying down usually works well for me. Can’t sleep without it, but couldn’t when I started taking it either. I’ve also heard good things about cbd/cbn, but I don’t know how available cbn is up there.
I may look, this is two points for sleep weeds in this thread c:
Have you tried light therapy? It sounds like your sleep/awake cycle is off and you can realign it with light therapy. There are devices that you can buy with the right wavelengths but those are expensive and there’s a lot of bad ones on the market that don’t actually work so you’d have to do some research on finding the right one. Easier is going outside every morning for a few minutes. Before noon the bluey wavelengths of sunlight signal our brain that it’s daytime, and our bodies start producing hormones that make us energetic. A few hours after noon the sunlight is more orangey which signals our brain that daytime is going to end in a few hours, and our bodies start producing hormones that makes us sleepy.
For me this was a life changing lesson. I don’t go outside every morning, just a few days in the week to remind my body how the cycle goes. If it’s sunny a few minutes staring in the direction of the sun is enough. If it’s cloudy then 15 minutes should do it. Looking through a window is not enough, you have to go outside for it (or watch through an open window I guess but then you’ll be surrounded with less light than outside so it might take longer). Obviously don’t ever look directly into the sun, it can be tricky to find a right angle but I usually focus my eyes somewhere above the sun. You also don’t have to look in the direction of the sun, you can look at another direction but for a longer duration.
I am willing to entertain this one but getting dressed to go out every day sounds like a trial holy shit, so Idk.
Lol I totally understand the barriers. It kinda depends on how you live. But for me I just stand in front of the door to my appartement complex for a few minutes and I don’t bother dressing up too much. I notice the difference immediately though which helps me stay motivated to do it. Also I definitely don’t do it every day, maybe once in every 2 or 3 days. Every day is better but yeah sometimes I just want to stay inside.
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Is it fine to use melatonin longterm that way? I always feel like I shouldn’t… I do try to remove screens a few hours before bed, I can feel the way they feed my stupid brain sometimes.
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Yes that’s my main concern too, adapting to it… But I guess I could just keep eating it?
I am sorry to hear you are going through a rough patch. I have had something similar going on and I found the only thing that helps is intense exercise at least 5 hours before bed time. What caused it for me was a mismatch between body energy and brain energy. When my mind would be exhausted before my body, my mind would switch off first. Then, I would be unable to sleep because of my excess body energy. Lying there, my brain would recharge some and my body would sublimate the body energy back into mind energy and I would be wired thinking.
Oh good, more intense exercise to add to my chronic pain adventures, I hate this
how do I realign brain and body energy…
I’m sorry I didn’t factor in chronic pain! It’s important to find something that works for your body. I found that weight training actually decreased my average amount of back pain because it helped me strengthen some stabilizers and imbalances.
No worries, and I do also have some (extremely small) weights I’m using to this end, Idk if it’s helping. I could move lifting to before bed…