>>At 08:30 AM 2/2/2001, Doug Alcock wrote:
>>Hi David --- maybe I'm completely missing the point here. I've been
>>putting the
>>black side up to the sun thinking that black absorbs the heat better. Should I
>>have the clear side up??? Am I about to feel very foolish............?>
>
>Yup.  Light passes through water, absorbs in black plastic and warms it,
>which in turn warms the water and sets up a convective current to pull down
>the cold water to be warmed.  With the heating layer on top you get only
>conductive and not convective mixing, takes way longer to warm the whole thing.
>
>d
>David Beierl - Providence, RI

Ahhhh ---- so I'm completely and utterly wrong (and glad to know it). I'll be
flipping my shower over right smartly. Thanks. I wonder which way Malcolm is
turning his shower over there in Egypt.........

Cheers,
Doug