Thursday, June 18, 2009

Light And Dark Shades

If we knew decades ago that global warming would become a danger to the world, what could we have done differently? One thing that immediately comes to mind is the shades of color (colour) on the large-scale structures built by human beings that face the sun. Most people know that dark shades absorb heat while light shades reflect heat.

If you take a look at satellite imagery of your hometown, or the nearest city for which such imagery is available online, on http://www.maps.google.com/ you will most likely see that most of what you see, streets, parking lots and, the roofs of large buildings, are dark and thus are absorbing more heat from the sun than if they were of a lighter shade. What we would need, of course, is asphalt that is light in shade. This would absorb much less solar heat and decrease global warming.

Moving vehicles should be just the opposite. A dark car will get better fuel mileage than a light car. This is because dark absorbs heat and causes the surface of the dark car to be hotter. This makes the air rise faster from the surface of the dark car and thus improves it's aerodynamics, meaning that it will use less fuel.

This principle has other applications as well. In my book, "The Patterns of New Ideas", I suggested that since heat in wires increases electrical resistance, the world would save a vast amount of electricity over time if all electrical wires exposed to the sun, on telephone poles and utility towers, were light in shade instead of the black that seems to be the rule.

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