NOOO!!!
America has its own laws of thermodynamics!
cryingwojak.jpg
Comment on Banana for scale
TomMasz@piefed.social 2 weeks ago
To be fair, it would be the same answer even if we used the metric system.
SwingingTheLamp@piefed.zip 2 weeks ago
GreyEyedGhost@piefed.ca 2 weeks ago
Yeah, but in one the math is super easy and you don’t need to throw in 6 conversion factors.
SwingingTheLamp@piefed.zip 2 weeks ago
Okay, then, how much energy does it take to boil 1mL of water from room temperature? (Note that I said “boil,” not raise it to 100°C.)
GreyEyedGhost@piefed.ca 2 weeks ago
We will assume that room temperature is 20° C. The heat of enthalpy is 2257 kJ/kg, or 2.257 kJ/g. As stated previously, the amount of energy to raise water 1 degree is 1 cal, which also equals 4.184 J. So,
(100-20) × 4.184 + 2257 = 80 × 4.184 + 2257 = 334.72 + 2257 = 2592 J rounded to the nearest whole number. This will leave you with a dry pot.
Now show me the process using Fahrenheit, fluid ounces, and foot-pounds.
SwingingTheLamp@piefed.zip 2 weeks ago
It’s about 1 BTU per fluid ounce per degree Fahrenheit, so:
128 fl oz × (212 - 68)°F × 1BTU/fl oz•°F = 18,432 BTU
Add in the enthalpy of vaporization:
7.5 BTU/fl oz × 128 fl oz = 960 BTU
So, about 19,392 BTU.
I’m cooking pasta for dinner, and I didn’t do any calculations. I just put the water in the pot on the stove, and waited for it to boil. Which was kind of the point of my question. Metric is all neat and elegant, but that’s irrelevant in daily life, because if I did have to calculate the energy requirement, I’d have to look up the enthalpy value, because it’s not memorable, as well as figuring in the actual atmospheric pressure to determine the actual boiling temperature. It makes all the sense in the world to use SI where it matters (e.g. science experiments), but customary units persist because in so much of daily life, it doesn’t matter.