Super White is Super Cool

You’ve probably heard that black cars get hotter than white cars.Scientists set out to measure the difference. They parked two otherwise identical cars in a sunny parking lot, and, sure enough, the white car’s interior stayed 17 degrees Fahrenheit cooler.Urban planners hope to use the same principle to cool cites, where miles of black asphalt and dark colored roofs absorb the sun’s heat, amplifying daytime temperatures, then radiate the heat through the night.The famous white villages of Spain have addressed this issue for centuries—by painting everything white.Today’s scientists are going a step further, creating super white paint, which could be used on buildings and rooftops.Standard white paint reflects 80 to 90 percent of visible light. This new paint uses calcium carbonate, or chalk, as a whitener and reflects 95 percent, cooling the surface temperature by 3 degrees Fahrenheit.An even more experimental paint uses barium sulfide. It reflects 98 percent of visible light and cools the surface by 8 degrees!If painted on a 1,000 square foot surface, it has more cooling power than a residential air conditioning system—yet requires no electricity.These paints are currently expensive, rare and fragile. But if perfected in the future, a simple coat of paint could lower the temperatures in cities. Now that’s cool!