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  • One watt per kilogram

    From Joy Beeson@21:1/5 to All on Thu Dec 7 21:23:03 2023
    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/

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  • From Radey Shouman@21:1/5 to John B. on Fri Dec 8 13:11:51 2023
    John B. <slocombjb@gmail.com> writes:

    On Thu, 07 Dec 2023 21:23:03 -0500, Joy Beeson
    <jbeeson@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.

    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 :-)

    --

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