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Temperature Conversion: Mental Calculation (2014)

susam.in

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Re: Temperature Conversion: Mental Calculation (2014)

#21

Post by Ragib_Zaman »

susam wrote: post #20
Ragib_Zaman wrote: post #14

Edit: The original comment below did not take into proper account the significance of taking the floor in the approximations, rendering it mostly useless. ---- If the "refined approximation" assumes it's easy to 1) subtract 10% 2) double and 3) add 31, then it should be just as easy to 1) double 2) subtract 10% and 3) add 32 - i.e. the exact conversion formula.

That's right. In fact, the latter would be just as easy as 1) subtract 10% 2) double 3) and add 32, i.e., the exact conversion formula again. In other words, (c - c/10) * 2 + 32 = 2c - 2c/10 + 32 = 9c/5 + 32. The only difference between the refined approximation and your approximation is 31 vs. 32 in the last step. The rationale for choosing 31 is explained in the "Analysis" section of the blog post. To summarize, wh…

Ahh fair enough. I should have spent more time understanding your rationale. I'll edit my original comment to reflect that.

Re: Temperature Conversion: Mental Calculation (2014)

#22

Post by stephen_g »

brownbat wrote: post #18
IgorPartola wrote: post #15

Or we can stop using freedom units and join the rest of the world. Take a small step to make this happen right now: set your phone and thermostat to show you the temperature in Celsius. I did this and my kids are growing up with an intuitive understanding of what 20 degrees C feels like.

I want to be careful, this could get holy war-ish... So I do not want to sell anyone on changing their view. This isn't advocacy. But just want to provide one illustration of why someone may prefer Fahrenheit. When I travel, hotel rooms generally let me alter the temperature on digital thermostats by one degree. In the US, that's great, that's plenty of precision. In Europe, I lose fidelity and am strictly worse off.…

To somebody who lives in one of the few hundred countries that uses Celsius, this just seems like a non-problem... While a lot of air conditioners adjust in single degree steps, plenty exist that go up or down in half degrees. A sous vide would probably adjust with a single decimal point. Digital thermometers basically also always do also. My weather app says it’s 16.1 degrees C outside right now... Easy...

Your comment about psychology is actually just you mistaking familiarity with your temperature system with something more universal. In countries where we use metric/Celsius, we find decimals super easy to think in because we’re used to doing it!

Re: Temperature Conversion: Mental Calculation (2014)

#23

Post by twic »

brownbat wrote: post #18
IgorPartola wrote: post #15

Or we can stop using freedom units and join the rest of the world. Take a small step to make this happen right now: set your phone and thermostat to show you the temperature in Celsius. I did this and my kids are growing up with an intuitive understanding of what 20 degrees C feels like.

I want to be careful, this could get holy war-ish... So I do not want to sell anyone on changing their view. This isn't advocacy. But just want to provide one illustration of why someone may prefer Fahrenheit. When I travel, hotel rooms generally let me alter the temperature on digital thermostats by one degree. In the US, that's great, that's plenty of precision. In Europe, I lose fidelity and am strictly worse off.…

The user interfaces let you input temperatures with more precision. But i would be astounded if the thermostats actually regulated the temperatures with that much accuracy. Have you tried measuring the temperatures actually attained?

Re: Temperature Conversion: Mental Calculation (2014)

#25

Post by Davertron »

Does anyone have resources for other shortcut calculations for similar things? This particular one comes up a lot when speaking with my wife's family (they're from Mexico) but I've never tried to come up with a shortcut before. I'd love to see links to other resources, or recommendations for Math tricks for doing quicker mental math.

Re: Temperature Conversion: Mental Calculation (2014)

#26

Post by IgorPartola »

brownbat wrote: post #18
IgorPartola wrote: post #15

Or we can stop using freedom units and join the rest of the world. Take a small step to make this happen right now: set your phone and thermostat to show you the temperature in Celsius. I did this and my kids are growing up with an intuitive understanding of what 20 degrees C feels like.

I want to be careful, this could get holy war-ish... So I do not want to sell anyone on changing their view. This isn't advocacy. But just want to provide one illustration of why someone may prefer Fahrenheit. When I travel, hotel rooms generally let me alter the temperature on digital thermostats by one degree. In the US, that's great, that's plenty of precision. In Europe, I lose fidelity and am strictly worse off.…

What if I want 0.25 degree adjustments? Can we all make and use a scale that lets me do that? This is a non problem for most of the world’s population. And if it is a problem, we can fix it by creating thermostats that work in C and let you have half degree adjustments. That’s your billion dollar idea.

Re: Temperature Conversion: Mental Calculation (2014)

#27

Post by kortilla »

IgorPartola wrote: post #17
duckymcduckface wrote: post #16

Earlier quoted context omitted.

You got them on meters and liters as well?

Liters don’t come up much and those are going to be a lot harder given that every gas station is in gallons only. Meters no, centimeters yes. They are 6 so they mostly measure small stuff. I use grams for cooking too. Who thought that “1 cup of cheese” was a reasonable measurement?

>Who thought that “1 cup of cheese” was a reasonable measurement?,

It’s easier to use a 1 cup scoop to grab something quickly than it is to weigh something out.

Re: Temperature Conversion: Mental Calculation (2014)

#28

Post by badamp »

brownbat wrote: post #18
IgorPartola wrote: post #15

Or we can stop using freedom units and join the rest of the world. Take a small step to make this happen right now: set your phone and thermostat to show you the temperature in Celsius. I did this and my kids are growing up with an intuitive understanding of what 20 degrees C feels like.

I want to be careful, this could get holy war-ish... So I do not want to sell anyone on changing their view. This isn't advocacy. But just want to provide one illustration of why someone may prefer Fahrenheit. When I travel, hotel rooms generally let me alter the temperature on digital thermostats by one degree. In the US, that's great, that's plenty of precision. In Europe, I lose fidelity and am strictly worse off.…

Temperature sensors in thermostats are nowhere near as precise as you seem to believe. And unless you have calibrated your sous vide to a standard I am willing to bet good money its not anywhere within 1 degree precision (having tested this.. you’re lucky to get +/- 3 C). Also nothing in cooking requires the precision down to fractional degrees C. You’re not going to obtain it anyway, even if you think you are.

Everything you’re saying is all in your head.

Re: Temperature Conversion: Mental Calculation (2014)

#30

Post by mikeash »

I memorize some 10s. 0 is 32, 10 is 50, 20 is 68, 30 is 86. Extend beyond what’s memorized by using the ratio 10/18. I don’t have 40 memorized, but it’s easy to figure that it’s 104. Then use the approximation of 1C=2F to fill in the gaps. High today is 34? That’s 94. Thermostat says 72? That’s 22.
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