Atmosphere of Earth trend begin above 11 km, where the temperature stabilizes through a large vertical distance through the rest of the troposphere. In the stratosphere, starting above about 20 km, the temperature increases with height, due to heating within the ozone layer caused by capture of significant ultraviolet radiation from the Sun by the dioxygen and ozone gas in this region. Still another region of increasing temperature with altitude occurs at very high altitudes, in the aptly-named thermosphere above 90 km. Because in an ideal gas of constant composition the speed of sound depends only on temperature and not on the gas
Sun protective clothing contains a benzene ring that absorbs UV light. In addition, UV absorbers may be added at various points in the manufacturing process to enhance protection levels. In 2003, chemical company BASF embedded nanoparticles of titanium dioxide into a nylon fabric, which can be used for sun protective clothing that maintains its UV protection when wet. There is some indication that washing fabrics in detergents containing fabric brighteners, which absorb UV radiation, might increase their protective capability. Studies at the University of Alberta also indicate that darker-colored fabrics offer more protection than lighter-colored fabrics. While there is some correlation between the