Aaron Toponce ⚛️Oct 7, 2024

Some of us are aware that -40° Celsius is also -40° Fahrenheit. It's the only point where the two scales agree.

But did you know there are palindrome temperatures and they're very useful also!

16° Celsius = 61° Fahrenheit
28° Celsius = 82° Fahrenheit

Show thread0x10f/kalle/qalleOct 7, 2024
@atoponce
11.43°F ≈ -11.43°C (sign change)
160°C = 320°F (double)
-12.3°F ≈ -24.6°C (double)
Show thread0x10f/kalle/qalleOct 8, 2024
@atoponce More approximate formulas:
- Celsius to Fahrenheit: add 14, then double. No more than 5 °C (9 °F) off between -25…65 °C = -13…149 °F ≈ -22…158 °F.
- Fahrenheit to Celsius: subtract 28, then halve. No more than 5 °C (9 °F) off between -22…158 °F = -30…70 °C ≈ -25…65 °C.
Show threadAaron Toponce ⚛️Oct 8, 2024

@0x10f I do something similar when in a pinch:

- °C → °F: double it and add 30
- °F → °C: subtract 30 and halve it

Show threadGavin GrahamOct 8, 2024
@atoponce @0x10f it's not much harder to do it accurately, subtract 32 and get 5/9... (Or get 9/5 and add 32 going the other way)
Nobody else enjoys the mental math??
Show threadAaron Toponce ⚛️Oct 8, 2024

@gavgraham @0x10f Yeah, but then it's more of a pain. Sometimes my brain gets jumbled.

EG: 65 °F → °C

65 - 32 = 33. Okay, 33 * 5 = ... uhm ... 5, carry the 1, ... , 15, 16, .... shit. 165? divided by 9, ... uh, ..., 2 drop the 5. 75, so not 9, then... goddammit, ... 18 °C?

Or

65 - 30 = 35 /2 ~= 18 °C. Good enough.

Show threadEarthworm 🐌

@atoponce

I love your visualization of mental math 😂

Oct 8, 2024 at 10:42amWeb