Using the information from the text, write a short summary.
Text 7
Learning about heat
The caloric theory of heat. Until the late 1700"s, many scientists believed that heat was an invisible fluid called caloric. They thought an object became warm when caloric flowed into it and grew cold when caloric flowed out of it. Because objects weighed the same whether they were hot or cold, the scientists reasoned that caloric had no weight and therefore could not be matter.
Near the end of the 1700`s, the work of two men raised questions about heat that the caloric theory could not answer. In 1798, the American-born scientist Benjamin Thompson, also known as Count Rumford, observed the manufacture of cannons in Munich, Germany. He noted that the drills used to bore the cannons produced frictional heat even after the drills became dull and no longer cut out metal. The caloric theory I could not account for the release of heat unless a drillactually cut metal. Yet an unlimited quantity of heat resulted as long as a drill turned against metal.
In 1799, the British chemist Sir Humphry Davy melted two pieces of ice by rubbing them together in a container at a temperature below the freezing point of water. Again, the caloric theory could not account forthe heat produced. Thompson's and Davy's observations raised doubts about the caloric theory. But no one proposed another explanation of heat.
Heat and energy. The idea that heat is a form of energy was proved during the mid-1800`S. The proof was developed largely by three men—Julius Robert von Mayer, a German physician and physicist; Hermann von Helmholtz, a German physicist; and James Prescott Joule- a British physicist
Mayer observed that people in warm and cold climates needed different amounts of food energy to maintain their normal body temperature. He published his findings in 1842, but they did not receive scientific recognition for many years. In 1847, Helmholtz published a work on heat and energy. He stated that heat is a form of energy, and the idea won rapid acceptance.
During the 1840s, Joule measured the amount of mechanical energy needed to raise the temperature of a certain quantity of water. The relationship between mechanical energy and heat energy is called the mechanical equivalent of heat. Joule's early experiments showed that 838 foot-pounds of mechanical energy produced 1 Btu of heat. Later scientists made more precise measurements. They found that the mechanical equivalent of heat was 778 foot-pounds per Btu, or, in the metric system, 4.184 joules per calorie. The joule was named for I James Prescott Joule.
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Thermodynamics is the study of the relationship between heat and other forms of energy. It is based on three laws (principles). The first law of thermodynamics is the law of conservation of energy. It states that energy is never created or destroyed.Energy may change form—for example, from Internal energy to mechanical motion—but the total quantity of energy in any system (group of things) remains the same.
According to the second law, all spontaneous (natural) eventsact to maintain the entropy within a system. Until a system reaches its maximum entropy, it can do I work. But as a system does work, its entropy increases until the system can no longer perform work.
The third law of thermodynamics concerns absolute zero. It states that it is impossible to reduce the temperature of any system to absolute Zero.
1. Study the following words:
Invisible fluid, weigh, frictional heat, rapid acceptance, mechanical equivalent of heat ., internal energy, precise, drills,
2. Translate into Russian:
a) The caloric theory I could not account for the release of heat unless a drillactually cut metal.
b) The relationship between mechanical energy and heat energy is called the mechanical equivalent of heat.
c) It states that energy is never created or destroyed
d) Yet an unlimited quantity of heat resulted as long as a drill turned against metal.
e) They found that the mechanical equivalent of heat was 778 foot-pounds per Btu, or, in the metric system, 4.184 joules per calorie.
3. Define the part of the speech of the following words:
Rubbing, Until, remain, entropy, measurement, state, impossible, according to
Within,
4. Find synonyms for the words in italics:
Observe, to maintain, entropy, release, rapid, destroy, increase, raise
5. Find antonyms to the following:
Invisible, precise, conservation, internal energy, motion, impossible
Text 6
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