Thermometer scales

The concept of temperature variation dates from antiquity, although early measurements were based solely on the subjective sense of touch. Touch is only capable of detecting temperature differences between objects; it cannot provide quantitative temperature data. For example, you may be able to tell if a person has a fever by placing a hand on their forehead (лоб), but exactly how high is the fever? That question requires quantitative data; our senses can mislead us, but a thermometer can give us that data.

Gabriel Fahrenheit (German, 1686-1736) devised the Fahrenheit scale, the oldest common temperature scale, in about 1714. (Prior to this, Galileo Galilei had invented an open tube thermometer in about 1593.) One of Fahrenheit` s innovation was to use mercury, which made the liquid column easy to see. Previously, people had had difficulty sealing mercury – containing tubes.

Fahrenheit established his temperature scale by selecting reference points he could reproduce. He designated a freezing ice-snow-salt-water mixture as 0°F because this was the lowest temperature he could create in his workshop. Several stories purport to explain his selection of the reference point for 100°F; my favorite is that he selected the body temperature of a cow, a measurement that interested him and other in the agricultural community. Starting with these primary reference points, Fahrenheit determined values of 32°F for the freezing point and 212°F for the boiling point of water.

Anders Celsius (Swedish astronomer, 1701- 1744) developed a different thermometer scale in 1742. Celsius designated the freezing and boiling points of water as 0°C and 100°C, respectively. His scale was originally called the centigrade scale because centi-means 1/100^th part, and the reference points span 100 degrees. The Celsius scale has been adopted worldwide and is the official metric temperature scale.

The third temperature scale was the invention of Englishman Lord Kelvin (born William Thompson, 1824-1907). Lord Kelvin devised his scale in 1848. It is identical to the Celsius scale, but all temperatures are 273 degrees higher. Thus, the freezing point of water is 273 degrees K, the boiling point 373 degrees K. This thermometer scale was derived from observation of gases.

part v

reading and discussing

Read the next texts and prove that observations often lead to the discoveries.

Vulcanization of Rubber (резина).

In February 1838 Charles Goodyear had a lucky accident when a mixture of sulfur and Indian rubber was brought carelessly into contact with a hot stove. He saw the mixture melt (плавиться) and react to form the product he had been trying to make for seven years. By this act and observation he discovered how to vulcanize rubber.

Crisis.

The combination of trial, observation, and deduction gives a method to meet changing conditions. Currently there is much talk of energy shortage (нехватка). The scientific method will probably help as it did in Pilgrim days. In 1615, James I of England found that his navy was short of wood and the supply was running out (запас истощался). He decreed that wood could no longer be used to stoke (поддерживать огонь) the glassmakers’ furnaces. This ruling seemed to mean the end of an industry. Actually, the glassmakers soon learned to use coal, an innovation at the time. But coal produced smoke and gases that were bad for the glass. A covered melting pot kept the smoke away from the molten glass and produced a bonus, higher temperature. This made it possible for George Ravens Сroft to make glass with a larger percentage of lead (свинец) oxide in it. His lead, or flint (кремень), glass was clearer and easier to carve and mold (резать и формовать). English glassmaking improved instead of dying.

Creating thermometer scales.

How do scientists such as Gabriel Fahrenheit and Anders Celsius create new concepts such as temperature scales? Many times, new discoveries stem from (происходить) a scientist` s personal interests or observations.

A cow` s normal body temperature is the same as a human` s – about 98.6° F. Yet some evidence indicates that Fahrenheit based his primary reference point for 100° F on the body temperature of a cow. If this story is true, the Fahrenheit scale was based on a sick cow! Some have claimed (утверждать) that Fahrenheit chose his value of 100° F so that the normal human body temperature would be 98.6° F, but this cannot be the case. While most people were aware (знать) that there was a normal human body temperature, its value was not determined until after the development of the thermometer scales. Instead, it seems that Fahrenheit based his scale on a measurement of interest to him.

Anders Celsius was a Swedish astronomer who had an interest in determining exactly how cold the Swedish night were as he walked to his observatory. Celsius wanted to know how warmly to dress and whether the metal telescope parts would be too cold to use in gazing at the vastness of the heavens (вглядываясь в безбрежное небо). The Celsius scale grew out of these practical concerns.

As you can see, scientists often have the same kinds of problems nonscientists do. Sometime, scientists view (рассматривать) those problems as an impetus (движущая сила, толчок) to study new ideas and invent new solution.

Part vi

rendering