Submitted 17 hours ago by xkcdbot@lemmy.world [bot] to xkcd@lemmy.world
https://imgs.xkcd.com/comics/farads.png
Title text:
‘This HAZMAT container contains radioactive material with activity of one becquerel.’ ‘So, like, a single banana slice?’
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: xkcd.com/3106/
This capacitor will cost around one Bitcoin
We use it to ignite the tokamak.
Only criticism is the use of non-metric weight units when everything else is SI-based.
Their names are Cueball, Megan, and White Hat?
It is my understanding that XKCD’s “characters” are somewhere between an actual character and an archetype. It isn’t clear…and kind of doesn’t matter, if Black Hat is the same guy in every comic or if he’s a different devious schemer in each. Randall hasn’t bothered to name any of them so the community has given them unofficial nicknames.
I remember reading about their names in explainxkcd. I think the only one never named in the comics is Cueball.
For a while, there was a blog, but I don’t think it named any character.
“This magnet has one tesla”
That stucks ;-)
Most neodymium magnets have like 7 Tesla at their surface.
It’s not that much though. You could easily make an electromagnet with magnetic flux density at it’s core of multiple tesla.
And you can get 1F capacitors in bulk from China for a few dozen dollars each.
Those things are still dangerous and scary. The 1T magnet way more so than the capacitor.
I used to teach AP physics to kids on the weekends. One asked me why Farads were so big. I had to explain that there’s a fixed ratio between Farads, Volts, and Joules. One of them had to be crazy big or crazy small.
See also Coulombs.
Caps are especially scary because they can develop their own charge through static electricity, so large value caps are often shipped with their terminals tied together.
There's nothing in the SI system that says ratios have to be between base units. Units that involve mass are defined against the kilogram not the gram.
You sent me down a freaking rabbit hole, thanks! :)
From what I found is that there is the simple reason that the weird ones are distance, time and weight - the rest I looked into are based on formal non-normalized definitions (including lumen, which surprised me).
My guess is that in depends on where the unit comes from: science or day to day use.
I learned about the Siemens, the Weber and the Gray on the way.
Thanks again!
However, 1 farad is really goddamn big.
Lol, explainXKCD
But why pick one pound? The are so many fun units to choose from, only some of which are conveniently sized. How about a stick 1 mile long, or a rock that weights 1 grain?
A rock that weighs one stone (14 lbs).
Or a barleycorn that’s one barleycorn long? Or a really large foot that’s a foot long. Or a chain that’s a chain long?
Ah, Randall is alive! I kept thinking my bot had broken as it’s so rare for him to miss an upload.
ryannathans@aussie.zone 17 hours ago
Haha that’s a good one
Capacitors are usually in the realm of pico to micro farads
A one farad capacitor charged to a respectable voltage would feel like a doomsday device in your hand
HakFoo@lemmy.sdf.org 17 hours ago
You see low voltage ones for things like memory backup on hi-fi gear. I have some 3F/5v capacitors in an old Technics tiner.
SalamenceFury@lemmy.world 17 hours ago
Wait so this is like one mistake away from turning that stickman into a fried stickman?
ricecake@sh.itjust.works 15 hours ago
Depends on the voltage it’s charged with, but household current would give it more energy than a shotgun has.
Realistically one would not do that unless you were dealing with something industrial. You would use them otherwise for things like dampening lower voltage systems that need a lot of current.
Closer to the danger level of someone holding two exposed wires plugged into the wall.
kaidezee@lemmy.ml 12 hours ago
That is why I like supercapacitors.
DarkCloud@lemmy.world 17 hours ago
Operation Sundial 2.0, electric boogaloo.