One watt per kilogram

[Joy Beeson]

I walked through the living room just when a lecture on sub-atomic
structure my spouse was watching compared the power density of the sun
to the power density of a human.

We put out in the general neighborhood of one watt per kilogram.
The sun has a *lot* of zeros after the decimal point,
but its mass has even more zeros before.

Reminds me of the time when I calculated that riding to Thatcher Park
from my home at the base of the Eastern Cliffs of the Helderbergs
imparted enough potential energy to heat a liter of ice water to the
boiling point.

The lecturer specified that the calories he was discussing were food
calories, AKA kilocalories, but the chart accompanying that discussion
faild to capitalize "Calorie".

--
Joy Beeson
joy beeson at centurylink dot net
http://wlweather.net/PAGEJOY/

[John B.]

The conversion of Kilocalorie's to watts of energy seems to be
https://www.unitconverters.net/power/kilocalorie-it-hour-to-watt.htm
For weight to power see
https://datacranker.com/cycling-power-to-weight-ratio-calculator/

BUT! This is a bit confusing as there are people who's weigh many
include a large quantity of fat, which produces no energy at all :-)

--
Cheers,

John B.

[Radey Shouman]

John B. <sloc...@gmail.com> writes:

> On Thu, 07 Dec 2023 21:23:03 -0500, Joy Beeson
> <jbe...@invalid.net.invalid> wrote:
>
>>
>>I walked through the living room just when a lecture on sub-atomic
>>structure my spouse was watching compared the power density of the sun
>>to the power density of a human.
>>
>>We put out in the general neighborhood of one watt per kilogram.
>>The sun has a *lot* of zeros after the decimal point,
>>but its mass has even more zeros before.
>>
>>Reminds me of the time when I calculated that riding to Thatcher Park
>>from my home at the base of the Eastern Cliffs of the Helderbergs
>>imparted enough potential energy to heat a liter of ice water to the
>>boiling point.
>>
>>The lecturer specified that the calories he was discussing were food
>>calories, AKA kilocalories, but the chart accompanying that discussion
>>faild to capitalize "Calorie".
>
> The conversion of Kilocalorie's to watts of energy seems to be
> https://www.unitconverters.net/power/kilocalorie-it-hour-to-watt.htm

4.184 J = 1.0 calorie
1W = 1J/s
1000 calorie = 1.0 Calorie

1 Cal/hr * 1000 cal/Cal * 4.184 J/cal * 1W/(J/s)* (1/3600 hr/s) = 1.16 W

Roughly, 1 Watt ~= 1 Calorie/hr

If converting Watts of work during exercise into Calories of food,
the efficiency of the conversion has to be estimated, and may be no
more accurate than the approximation above.