The black ball idea catched my attention. I copy it here for my learning diary. Department of Water and Power workers are emptying out bales of plastic balls in the Ivanhoe reservoir in Los Angeles on Monday, June 9, 2008. Department of Water and Power released about 400,000 black plastic 4-inch balls as the first installment of approximately 3 million to form a floating cover over 7 acres of the reservoir to protect the water from sunlight. When sunlight mixes with the bromide and chlorine in Ivanhoe's water, the carcinogen bromate can form. (Irfan Khan/AP)
Saturday, December 20, 2008
Black Balls
The black ball idea catched my attention. I copy it here for my learning diary. Department of Water and Power workers are emptying out bales of plastic balls in the Ivanhoe reservoir in Los Angeles on Monday, June 9, 2008. Department of Water and Power released about 400,000 black plastic 4-inch balls as the first installment of approximately 3 million to form a floating cover over 7 acres of the reservoir to protect the water from sunlight. When sunlight mixes with the bromide and chlorine in Ivanhoe's water, the carcinogen bromate can form. (Irfan Khan/AP)
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5 comments:
Why not white, to reflect the heat? Would you not expect the black plastic bals to absorb heat, and radiate it into the water surface, increasing evaporation, ie water loss?
Your comment seems perfectly logical. I dont know why black balls are better at preventing evaporation than white or aluminized reflecting balls.
Desert goats and Arab galabiyyah are black, but I heard that the problem in the desert is not during the daylight but conserving heat during the cold nights. In one word: I dont know.
I wish I could erase my former comment, as googling the question I got the answer.
It is well known that a black-coloured aluminum heat sink
radiates warmth better than a chrome-plated heat sink or an not plated aluminum heat sink. Physics theory predicts that the heat radiated per unit of surface area for a black-body, is 2 times the heat radiated from a 100% reflective surface.
I wish I could erase my former comment, as googling the question I got the answer.
It is well known that a black-coloured aluminum heat sink
radiates warmth better than a chrome-plated heat sink or an not plated aluminum heat sink. Physics theory predicts that the heat radiated per unit of surface area for a black-body, is 2 times the heat radiated from a 100% reflective surface.
J:
In the case of an aluminum heat sink the statement is true. Aluminum is a conductor. The balls are insulators and do not have the same properties.
That being said, my take on the color being Black is that the color Black in plastic material generally holds up better in the summer sun.
dg
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