Why should air temperature measurements be made in the ...

[Themember4]

Why should air temperature measurements be made in the shade?

Question 2

Some sailors, even in ancient times, would dump oil into the sea during stormy weather, claiming it reduced the winds around the ship. Could this practice work? Why or why not?

[polinasid]

Answer to Question 1

It is impossible to measure air temperature accurately in direct sunlight because the thermometer absorbs radiant energy from the sun in addition to energy from the air molecules. The thermometer gains energy at a much faster rate than it can radiate it away, and the liquid keeps expanding and rising until there is equilibrium between incoming and outgoing energy. Because of the direct absorption of solar energy, the level of the liquid in the thermometer indicates a temperature much higher than the actual air temperature.

Answer to Question 2

Recent mathematical studies have shown that ocean spray has an effect on the winds of a hurricane. Apparently, the tiny spray reduces the friction between the wind and sea surface. Therefore, with the same pressure gradient, the more ocean spray, the higher the winds. So, limiting ocean spray from entering the air above by dropping oil onto the ocean water may reduce the storm's winds. Without knowing the mathematical reasons, the ancient sailors, by dumping oil into the sea, may have actually been preventing very strong winds and even hurricanes.