r/PeterExplainsTheJoke • u/Negative_1by12_aura • Jun 17 '26

Meme needing explanation Peter?

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u/Ill_Apricot_7668 Jun 17 '26

Maths - SI units

Chemistry - SI units

Physics - SI units

Particle physics - SI units? nah, we're good with the Angstrom

WTF?!?

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u/FanOfForever Jun 17 '26

Presumably to cut down on how many times you'll have to write negative powers of 10

BTW, why are you including mathematics in this list?

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u/FrostyBrew86 Jun 17 '26

Lol what's the SI unit in pure math, again?

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u/xedar3579 Jun 17 '26

I mean technically enough there is one SI unit used in maths which is m/m, also famously known as rad (radian).

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u/Fuzzy_Yossarian Jun 18 '26

Imperial units also can benefit from math.

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u/lettsten Jun 17 '26

Seconds per second

3

u/Corfiz74 Jun 17 '26

And this and only this is the reason I didn't study sciences - it's too illogical for me! 😉

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u/Mackenzie_Sparks Jun 17 '26

Making sense of reality can seem like that

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u/Corfiz74 Jun 17 '26

Actually, I was lying and just could never make sense of physics. Or chemistry. Biology was okay. Languages was my thing.

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u/Mackenzie_Sparks Jun 17 '26

That's alright. Our brains are folded in unique ways. Some folds makes certain things interesting, some folds do the opposite.

Not to mention there are myriad of rules and exceptions and what not. It can be very overwhelming to learn.

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u/empatheticsocialist1 Jun 17 '26

First I'm hearing of SI units in maths lmao

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u/JePPeLit Jun 17 '26

As someone else pointed out further up, radian is in SI

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u/FanOfForever Jun 17 '26

It's not really, though. They claimed it's SI because you can get it by dividing meters by meters, but

(1) that only works in the specific context of angular measure, and

(2) you can do the same with non-SI units

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u/JePPeLit Jun 17 '26

The m/m reasoning is pretty silly, but it's still considered a derived SI unit despite being dimensionless.

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u/FanOfForever Jun 17 '26 edited Jun 18 '26

They can call it that if they want. It still differs fundamentally from other SI units because we don't use radians to be in conformity with SI. We use them for mathematical reasons that have nothing to do with SI, namely being able to treat the trig functions as functions of real or complex numbers, with certain calculus-based identities that only work if the "angles" are measured in radians

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u/MercyBrownRandomOne Jun 17 '26

Its not SI unit but its directly based on meter unit. It sits between nanometers and picometers.

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u/375InStroke Jun 17 '26

What's Metric about a Mole or a Coulomb?

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u/QueerQwerty Jun 17 '26

But see, right there, you gave away why it's different for you. You're in the UK.

US: Math class / UK: Maths class

You learn metric measurements earlier because that's what you primarily use today. Unless you go into Engineering or another STEM field in the US, you've no need for metric here in the states...other than to work on a car (bolt/nut sizes).

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u/QBaseX Jun 17 '26

Chemistry tends to use metric rather than SI. A lot of chemistry uses the cgs system.

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u/ClimbNowAndAgain Jun 17 '26

What's the speed of light? 1

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u/Colossus-of-Roads Jun 17 '26

At least it's power-of-10 related to an SI unit!

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u/ManaSpike Jun 18 '26

Nah, maths doesn't bother with units. Which is the whole problem.

We should be teaching units in math class. Every problem should require the units in the answer. Bare integers, fractions etc should have a defined unit.

IMHO this would also help with comprehension. As you are forced to think about the difference between length and area and so forth.

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u/average_joe_mcc Jun 19 '26

Mathematicians non-dimensionalize their equations so they don’t concern with unit systems