janus2

janus2 OP , 9 months ago

ah, Freedom Units…

Added the book to my list :]

janus2 OP , 9 months ago

It’s one of my favorite books of all time 😁 to the point where I own a hardback of it despite being staunchly pro-just-read-books-on-my-phone

IIRC they actually printed a centimeter ruler in the back of the book as an answer to this specific problem.

janus2 OP , 9 months ago

Re Celsius 0 °: the reason I thought perhaps Fahrenheit’s Weird Brine might be a more absolute thing to take de novo temperature from was because I don’t actually know the answer to “how can you ensure water is exactly freezing temperature?” If it’s solid ice it could be colder, if it’s liquid it’s probably warmer, and even if it’s a bucket of cold distilled water with distilled water ice in it, isn’t it still likely hotter than 0 ° C? I feel like there’s probably something involving equilibrium between solid and liquid water that would be difficult to sus out

Not that Weird Brine is any better really 🤦‍♀️

janus2 OP , 9 months ago

I hadn’t even thought about getting HH:MM from a sundial, that’s brilliant! Then getting seconds and the meter from a pendulum is just straight up elegant.

By careful geometry you could reduce tge size of your first container to make this easier, but keeping it big and then dividing the result minimises measurement errors.

I thought this was worth a callout for being a really important consideration in this thought experiment. Understanding that larger scale measurements generally reduce error, and perhaps also repetition with averaging of results, would be incredibly useful in fast tracking the redevelopment of precision.

If you have accesd to ice, letting it just melt gives you 0c.

This one I wondered about more because of the effect of atmospheric pressure(?) on melting point, such that I wondered if it would be worth using Fahrenheit’s Weird Brine ice slurry to get ~ -17.778 ° C instead. But that’s ofc also subject to air pressure influencing melting point so I’m unsure if it’d be worthwhile.

Relatively constant 9.81 m/s² gravity is also useful for deriving force as you mention, though it reminds me of learning, to my abject horror, in undergrad physics that gravity does vary quite a bit by geolocation :'D 9.81m/s² is a better starting point than nothing though

janus2 OP , 9 months ago

That’s a fair point. Most likely if a group of people did some kind of Long Term Naked & Afraid experiment they’d just start with some length of particularly well-crafted cordage, call it a New Meter™ and go from there

janus2 OP , 9 months ago

Interestingly, if you have your meter measure you could use that to measure atmospheric pressure by seeing how far you could raise water in a column by suction. At standard atmospheric pressure you should be able to lift fresh water 10.3m.

Oh yeah! I should have remembered that actually, since I was just rewatching an episode of Connections 2 that mentions this height limit in the context of vacuum pump history (I think it’s detailed more in season 1 but I forget which episode). So 10.3 m is another key measurement that you want at least one human to have memorized :]

Gravity is altogether too unreliable and should be abolished.

This reads like a Douglas Adams quote and I love it.

janus2 OP , 9 months ago

Ah, so at sea level a bucket of ice water would make a decent approximation of 0 ° C, then, I suppose.

Didn’t know really tiny ice particles spontaneously fused, this is neat to know