> 
> About 120 Watts.  ((2,500 Calories/day) * (4186 
> Joules/Calorie) / (86,400 
> sec/day) = 121.1 Joules/sec, a calculation I perform on the 
> board every 
> time we start talking about energy in various forms, since to 
> most people 
> today, a "Calorie" is simply a measure of how much fatter you 
> get by eating 
> something rather than the amount of heat necessary to raise 
> the temperature 
> of one kilogram of water 1�C.)

Hold on. I remember from Physics 101 that a food calorie is different than a
"Calorie" or CAL that we measured with a home made calorimeter(heat bomb?).
Is not a food calorie really a Kilocalorie - or is it the other way around?
Nerd From Hell


> 
> With 30-odd students all in the same room (I haven't measured 
> it, but I 
> doubt that the area of the classroom is > 900 ft�) along with 
> one very-odd 
> instructor who is spouting hot air, it does indeed get stuffy 
> unless we can 
> have the door open.  However . . .
> 
> 
> 
> > > It would be intolerably miserable at best on the coldest 
> winter day.
> 
> 
> 
> . . . 1 human/900 ft� means one human in a fair-sized room.  
> None of the 
> rooms in my house come anywhere close to 900 ft�.  In fact, I 
> think that 
> would be close to half the living area of the whole house, 
> and for many 
> years this house housed three humans and still needed to be 
> heated during 
> even an Alabama winter.  My grandparents' house was even 
> smaller, and still 
> had to be heated even when the entire family gathered in one 
> room to open 
> Christmas presents.
> 
> (Now, on a summer day with both the computer and the TV/VCR 
> running, it 
> does get a tad warm here in the immediate vicinity . . . )
> 
> 
> 
> >Homework problem: look up the power per square meter of 
> sunlight on the
> >earth's surface, and compare to the power produced by 1 
> human per 900 sq
> >ft. Comment on the absurdity of the above statement.
> 
> 
> 
> The first figure is called the "solar constant" (actually, 
> this is measured 
> above the atmosphere):  1.37 kW/m�.
> 
> 1 m = 3.28 feet, so 1 m� = 10.76 ft�, so 900 ft� = 83.6 m�, 
> thus the power 
> of the sunlight falling on 900 ft� of Earth is  (1.37 kW/m�) 
> * (83.6 m�) = 
> 114.6 kW, or nearly 1,000 times the power in the form of heat 
> given off by 
> a person.
> 
> 
> 
> 
> -- Ronn! :)
> 
> Ronn Blankenship
> Instructor of Astronomy/Planetary Science
> University of Montevallo
> Montevallo, AL
> 
> Disclaimer:  Unless specifically stated otherwise, any 
> opinions contained 
> herein are the personal opinions of the author and do not 
> represent the 
> official position of the University of Montevallo.
> 
> 

Reply via email to