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Posted by SteveC on August 13, 2008, 12:46 pm
Please log in for more thread options I lost you at "Lake Superior covers about 31000 square miles".
All I know is that's a lot of water savings, now matter how you do the
calculations.
I'm on a well, so shag it!!!!!!!
Steve
> How much water is 1 gallon/day/person?
>
> I saw an ad on television that stated that if everyone used
> 1 gallon of water less per day, in one year enough water would
> be saved to fill (US) Lake Superior more than 30 times over.
>
> While saving 1 gallon per day per person is a significant amount
> (New York City uses about 1 billion gallons a day, so with 7 billion
> people the water savings is enough for about 7 NYCs), I think
> that a year's worth of such savings is small compared with the
> volume of Lake Superior.
>
> Lake Superior covers about 31000 square miles and has a volume of
> about 2900 cubic miles. A cubic foot is more than 7 gallons.
> (Volume from "World Almanac and Book of Facts 2006", and Wikipedia.)
>
> There are about 7 billion people and less than 400 days a year,
> so there would be a savings of less than 2800 billion gallons/year.
>
> However the lake contains more than
> (2900 cubic miles)* (7 gallons/cubic foot) *
> (5280*5280*5280 cubic feet per cubic mile)
>
> This is more than
> 2900 billion *5*5*5*7 gallons
>
> I.e., the volume of Lake Superior is more than
> 2900 billion * 125*7 gallons
>
> Comparing to 2800 billion gallons saved per year,
> we see that the volume of the lake is more than
> 875 (125*7) times the volume of water saved in a year,
> so the "fill Lake Superior over 30 times" wrong by a factor
> more than 25000 (875*30).
>
> In fact, I think that the ad referred to the US population
> of 300 million, not the world population of 7000 million,
> so the comparison is off by a factor more than 1/2 million.
>
> By the way, does anyone know the source of the ad?
> I want to tell them their numbers are more than a little wrong.
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