- published: 01 Mar 2016
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The atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night (the diurnal temperature variation).
Atmospheric stratification describes the structure of the atmosphere, dividing it into distinct layers, each with specific characteristics such as temperature or composition. The atmosphere has a mass of about 5×1018 kg, three quarters of which is within about 11 km (6.8 mi; 36,000 ft) of the surface. The atmosphere becomes thinner and thinner with increasing altitude, with no definite boundary between the atmosphere and outer space. An altitude of 120 km (75 mi) is where atmospheric effects become noticeable during atmospheric reentry of spacecraft. The Kármán line, at 100 km (62 mi), also is often regarded as the boundary between atmosphere and outer space.
Caramel ( /ˈkærəmɛl/ or /ˈkɑrməl/ ) is a beige to dark-brown confectionery product made by heating any of a variety of sugars. It is used as a flavoring in puddings and desserts, as a filling in bonbons, and as a topping for ice cream, custard and coffee.
The process of caramelization consists of heating sugar slowly to around 170 °C (340 °F). As the sugar heats, the molecules break down and re-form into compounds with a characteristic color and flavor.
A variety of candies, confections, and desserts are made with caramel: caramel apples, pralines, nougats, brittles, crème caramel, and crème brûlée.
Most linguists trace the origin of the word to Medieval Latin cannamellis (sugar cane) or to Latin callamellus (little reed, referring to sugar cane).
Caramel candy is a soft, dense, chewy candy made by boiling a mixture of milk or cream, sugar(s), butter, and vanilla flavoring. The sugar(s) are heated separately to reach 170 °C (340 °F), caramelizing them before the other ingredients are added. Alternatively, all ingredients may be cooked together; in this procedure, the mixture is not heated above the firm ball stage (120 °C (250 °F)), so there is caramelization of the milk but not of the sugars. This type of candy is often called "milk caramel" or "cream caramel".