TIL, I can totally enrich uranium with a modified dental drill.
Well, I'm off to start a new project, I'll let everyone know how it goes.
this post was submitted on 06 Feb 2025
227 points (99.6% liked)
xkcd
9741 readers
23 users here now
A community for a webcomic of romance, sarcasm, math, and language.
founded 2 years ago
MODERATORS
Isn't record 78rpm instead of 72rpm?
Yes.
It's probably a PAL record instead of NTSC.
You'd think the WR would a lot higher...
A lot of people won't notice the difference.
"Sidereal" pronounced /saɪˈdɪəriəl, sə-/ sy-DEER-ee-əl, sə-
meaning "of the stars" (from Latin, as opposed to Astral from the Greek)
used in modern English in "consider" (literally: with the stars, meaning to scrutinize the sky).
Subscribe
Nah, that's sub + scribere: "write under", as in signature. No relation to sidereal.
What would the bird version of "consider" be?
Conavis?
I get I never learned phonetics but how tf do you pronounce upside down e
It's the phonetic symbol for schwa, which is like a relaxed "uh" sound.
Oh it's so obvious now.
Side real
Like ethereal
300 RPM for screwdriver ??? I guess it's electric/machine ones, because no one in gods green earth can turn regular screwdriver 300 RPM
Stupid question… are these RPMs true??
Everything in XKCD is based on truth. That's what makes it so funny... to geeks, at least.
Edit: God damn it, he put 72 instead of 78 RPM. I guess he does make mistakes after all...
He also put 33 instead of 33 and ⅓. Get the pitchforks!
Just a random thought, I always knew that 33 multiplied by 3 is 99 and 33 1/3 multiplied by 3 is 100, but I never considered that 33 is 99% of 33 1/3.
Woah...
He's made typos a few times in the past too: https://explainxkcd.com/wiki/index.php?search=typo&title=Special%3ASearch&go=Go
I mean, technically, the record will play just fine. Everything will be slightly slower and lower pitched, but it'll work. Think doom metal meets 1930s jazz.
Maybe I'm dense but shouldn't the clock be:
- H: 0.01667
- M: 1
- S: 60
Yep, I'm a dumb, realized after a cup of coffee. Confirmed by the reply below.
I think I'm just going to go back to bed and skip today
Yes, you're dense lol. The speeds are correct: the second hand that does one full Revolution Per Minute, the minute hand does one full Revolution Per Hour and the hour hand does one Revolution Per 12 Hours.
Oh my god I'm full of caffeine and still wondered this same thing. In my defense it's Friday afternoon and I'm tired.
The sidereal telescope mount one seems to be right (approx 1 rotation per day).
Wow, dental drills spin stupidly fast. I never realized they're jamming something in my mouth that makes a turbopump seem sluggish, and that makes the scariest laboratory centrifuge I've ever seen blush in shame.
Big centrifuges are quite scary. Think of how much mass they are moving at those speeds. In comparison, a small drillbit turbine being rotated by compressed air seems less scary.
The scariest lab centrifuge i've personally seen went to something like 100k rpm, and 800,000 g. It's basically a cartoon safe with a piece of lab equipment inside, because when something fails at 800,000 times the force of gravity, it's going to end up outside the city borders, or inside the next building over.
I occasionally run a lathe at work. The big CNC one says it will do 10,000 rpm
If you ever run it that fast, the jaws will start to separate and the part will come flying out at Mach 4, bounce around the inside of the machine for several minutes, destroying the chuck, all the tooling, and the chip conveyor in the process.
Another fun fact, these machines go from 5000 rpm (the fastest you're assuredly safe to run it) to 10 at the snap of a finger and back up again. All of that energy has to go somewhere. So there's a heat coil, pretty much identical to the one in your oven, that takes all that extra energy. It doesn't normally get all that hot, but if you're running a lot of parts with a lot of diameter changes, it can get hot enough to glow.