Solution to

Notice that the last problem has a negative answer. In the Celsius

Frame 4-46

system, 0 C is the freezing point of pure water; temperatures above

a. 0 [32 32 = 0

freezing are positive values, and temperatures below freezing (below 0

0 x 5/9 = 0;

C) are denoted by negative numbers (numbers with a negative or minus

sign in front). Negative values will be discussed in Lesson 5.

b. 37.8. [100 32 =

68; 68 x

Is an object that has a temperature of 100 C twice as hot as an object

0.5556 =

that has a temperature of 50 C?

37.7808]

c. 100 [21232 =180

Is an object that has a temperature of 100 F twice as hot as an object

180 x 5/9 =

that has a temperature of 50 F?

100]

The answer to both of the above questions must be, "No," because we

d. 17.8 [0 32 =

know of temperatures that go below 0 on each scale. But scientists

32;

desired a system of measurement in which the temperature measured

32 x 5/9 =

the heat energy of an object, beginning with no heat energy. They gave

17.7778]

the term "absolute zero" to this temperature. In 1848, William Thomson

(later Baron Kelvin of Largs) introduced the absolute temperature scale

based upon the Celsius scale. In this thermodynamic scale of

temperature, an object with a temperature of zero has no heat energy.

This temperature is referred to a zero kelvin (0 K). The freezing point of

water is 273.15 K and the boiling point of water is 373.15 K. In 1954, the

kelvin scale was adopted as the SI standard.

NOTE: Originally, temperature was denoted in degrees Kelvin ( K), but

was later changed to kelvin (K) without the degree symbol. When

spelled out, kelvin is spelled without the capital letter. The abbreviation

for kelvin remains a capital letter (K).

The temperature at which an object contains no heat energy is

.

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Solution to

Frame 4-47

A temperature of absolute zero (0 K) on the Celsius scale is 273.15 C.

On the Fahrenheit scale, absolute zero is 459.67 F.

0 K (zero kelvin)

a. The temperature at which pure water freezes is

K.

b. The temperature at which pure water boils is

K.

c. Of the Fahrenheit, Celsius, and kelvin scales, which has/have no

negative temperatures?

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MD0900

4-24

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