Why is it cooler at higher altitudes?

Air in the atmosphere is not heated directly by the sun. It's the surface of the Earth that's heated by the sun and the layer of air in immediate contact with the Earth's surface gets heated due to conduction. As Cheap Bay Ban Sunglasses you go away from the surface of the Earth, the heating by conduction keeps decreasing and, therefore, it is cooler at higher altitudes. That is the basic explanation. There are other factors like rising of the air in immediate contact with the surface of the Earth due to heating and, thereby, distributing heaf to the upper layers. What's the origin of 'touch wood'? There are several theories. According to one, it originates from the pagan belief that good spirits reside in trees such as oak, and hence, touching wood or knocking on wood would help ward off evil spirits. According to Discount Gucci Sunglasses an ancient Celtic belief, trees can conduct evil spirits, much like a conductor absorbing heat. Some would knock'on wood to thank mythical creatures named leprechauns for bestowing good luck. Also, since Jesus Christ was crucified on a wooden cross, touching a wooden crucifix was, therefore, a form of praying for good luck. How does a cryogenic engine work? The cryogenic engine gets its name from the extremely cold temperature at which liquid nitrogen is stored. Air moving around the vehicle is used to heat liquid nitrogen to a boil. Once it boils, it turns to gas in the same way that heated water forms steam in a steam engine. A rocket like the Ariane 5 uses oxygen and hydrogen, both stored as a cryogenic liquid, to http://www.urbanstylesoutlet.com/ produce its power. The liquid nitrogen, stored at -320 degrees Fahrenheit, is vaporized by the heat exchanger. Nitrogen gas formed in the heat exchanger expands to about 700 times the volume of its liquid form. This highly pressurised gas is then fed to the expander, where the force of the nitrogen gas is converted into mechanical power. Best Quality Chanel Sunglasses 2013 EN Mar-22