mindmap root((THERM/THERMO)) thermal 1、 Of, relating to, or caused by heat.
2、 Designed to insulate in order to retain body heat.
🌱A special weave called thermal weave traps insulating air in little pockets to increase the warmth of long underwear and blankets. 🌳In days gone by, much of the male population of the northern states in the cold months would wear a garment of thermal underwear covering the entire body, called a union suit. Union suits kept sodbusters, cowboys, and townsfolk alike not only warm but also itchy and a little on the smelly side （back when bathing once a week was considered the height of cleanliness）. Thermal imaging is photography that captures "heat pictures"—rather than ordinary light pictures—of objects. And thermal pollution occurs when industrial water use ends up warming a river in a damaging way. Small-plane pilots use thermal as a noun for a warm updraft, often over a plowed field or desert, that lifts their wings, just as it enables hawks to soar upward without moving their wings. thermodynamics Physics that deals with the mechanical actions or relations of heat.
🌱With his college major in electrical engineering, he assumed it would be an easy step to a graduate-school concentration in thermodynamics. 🌳Thermodynamics （See DYNAM）is based on the fact that all forms of energy, including heat and mechanical energy, are basically the same. Thus, it deals with the ways in which one form of energy is converted into another, when one of the forms is heat. The study of thermodynamics dates from before the invention of the first practical steam engine—an engine that uses steam to produce physical power—in the 18th century. Today most of the world's electrical power is actually produced by steam engines, and the principal use of thermodynamics is in power production. thermonuclear Of or relating to the changes in the nucleus of atoms with low atomic weight, such as hydrogen, that require a very high temperature to begin.
🌱In the 1950s and '60s, anxious American families built thousands of underground "fallout shelters" to protect themselves from the radiation of a thermonuclear blast. 🌳Nuclear is the adjective for nucleus, the main central part of an atom. The original nuclear explosives, detonated in 1945, were so-called fission bombs, since they relied on the fission, or splitting, of the nuclei of uranium atoms. But an even greater source of destructive power lay in nuclear fusion, the forcing together of atomic nuclei. The light and heat given off by stars such as the sun come from a sustained fusion—or thermonuclear—reaction deep within it. On earth, such thermonuclear reactions were used to develop the hydrogen bomb, a bomb based on a fusion reaction that merged hydrogen atoms to become helium atoms. The thermonuclear era, which began in 1952, produced bombs hundreds of times more powerful than those exploded at the end of World War II. Why the thermo- in thermonuclear? Because great heat is required to trigger the fusion process, and the trigger used is actually a fission bomb. British thermal unit The quantity of heat required to raise the temperature of one pound of water one degree Fahrenheit at a specified temperature.
🌱Wood-stove manufacturers compete with each other in their claims of how many British thermal units of heat output their stoves can produce. 🌳Despite its name, the British thermal unit, or BTU, may be more widely used in North America than in Britain. Air conditioners, furnaces, and stoves are generally rated by BTUs. （Though "BTUs" is often short for "BTUs per hour"; in air-conditioner ratings, for instance, "BTUs" really means "BTUs of cooling capacity per hour."） Fuels such as natural gas and propane are also compared using BTUs. The BTU first appeared in 1876 and isn't part of the metric system—the metric unit of energy is the much smaller joule—so it isn't much used by scientists, but its practicality keeps it popular for consumer goods and fuels. A better-known heat unit is the calorie; a BTU is equal to about 252 calories. （Since the familiar food calorie is actually a kilocalorie, a BTU equals only about a quarter of a food calorie.）