This document discusses temperature conversions between different temperature scales. It explains that the Fahrenheit, Celsius and Kelvin scales are used to measure temperature and have defined reference points for the freezing and boiling points of water. The document provides examples of converting temperatures between the different scales using defined formulas. It also introduces the Kelvin scale which has its lowest point of 0 K at -273°C and defines 100 K between the freezing and boiling points of water.

1. 1
Chapter 2 Energy and Matter
2.3
Temperature Conversions
Copyright © 2005 by Pearson Education, Inc.
Publishing as Benjamin Cummings

2. 2
Temperature
Temperature
• is a measure of how hot or cold an
object is compared to another object.
• indicates that heat flows from the
object with a higher temperature to
the object with a lower temperature.
• is measured using a thermometer.
Copyright © 2005 by Pearson Education, Inc.
Publishing as Benjamin Cummings

3. 3
Temperature Scales
Temperature
Scales
Copyright © 2005 by Pearson Education, Inc.
Publishing as Benjamin Cummings
• are Fahrenheit,
Celsius, and
Kelvin.
• have reference
points for the
boiling and
freezing points
of water.

4. 4
A. What is the temperature of freezing water?
1) 0°F 2) 0°C 3) 0 K
B. What is the temperature of boiling water?
1) 100°F 2) 32°F 3) 373 K
C. How many Celsius units are between the boiling and
freezing points of water?
1) 100 2) 180 3) 273
Learning Check

5. 5
A. What is the temperature of freezing water?
2) 0°C
B. What is the temperature of boiling water?
3) 373 K
C. How many Celsius units are between the boiling and
freezing points of water?
1) 100
Solution

6. 6
• On the Fahrenheit scale, there are 180°F between the
freezing and boiling points and on the Celsius scale,
there are 100°C.
180°F = 9°F = 1.8°F
100°C 5°C 1°C
• In the formula for the Fahrenheit temperature, adding
32 adjusts the zero point of water from 0°C to 32°F.
TF = 9/5 TC + 32°
or
TF = 1.8 TC + 32°
Fahrenheit Formula

7. 7
• TC is obtained by rearranging the equation for TF.
TF = 1.8TC + 32
• Subtract 32 from both sides.
TF - 32 = 1.8TC ( +32 - 32)
TF - 32 = 1.8TC
• Divide by 1.8 = °F - 32 = 1.8 TC
1.8 1.8
TF - 32 = TC
1.8
Celsius Formula

8. 8
Solving A Temperature Problem
A person with hypothermia has a
body temperature of 34.8°C.
What is that temperature in °F?
TF = 1.8 TC + 32°
TF = 1.8 (34.8°C) + 32°
exact tenth's exact
= 62.6 + 32°
= 94.6°F
tenth’s Copyright © 2005 by Pearson Education, Inc.
Publishing as Benjamin Cummings

9. 9
The normal temperature of a chickadee is 105.8°F.
What is that temperature on the Celsius scale?
1) 73.8°C
2) 58.8°C
3) 41.0°C
Learning Check

10. 10
3) 41.0 °C
TC = (TF - 32°)
1.8
= (105.8 - 32°)
1.8
= 73.8°F = 41.0°C
1.8°
Solution

11. 11
A pepperoni pizza is baked at 455°F. What
temperature is needed on the Celsius scale?
1) 423°C
2) 235°C
3) 221°C
Learning Check

12. 12
A pepperoni pizza is baked at 455°F. What
temperature is needed on the Celsius scale?
2) 235°C
TF - 32° = TC
1.8
(455 - 32°) = 235°C
1.8
Solution

13. 13
On a cold winter day, the temperature is –15°C.
What is that temperature in °F?
1) 19°F
2) 59°F
3) 5°F
Learning Check

14. 14
3) 5°F
TF = 1.8 TC + 32°
TF = 1.8(–15°C) + 32°
= – 27 + 32°
= 5°F
Note: Be sure to use the change sign key on
your calculator to enter the minus – sign.
1.8 x 15 +/ – = –27
Solution

15. 15
The Kelvin temperature scale
• has 100 units between the freezing and boiling points
of water.
100 K = 100°C or 1 K = 1°C
• is obtained by adding 273 to the Celsius temperature.
TK = TC + 273
• contains the lowest possible temperature, absolute
zero (0 K).
0 K = –273°C
Kelvin Temperature Scale

16. 16
Temperatures
TABLE 2.5

17. 17
What is normal body temperature of 37°C in Kelvins?
1) 236 K
2) 310. K
3) 342 K
Learning Check

18. 18
What is normal body temperature of 37°C in kelvins?
2) 310. K
TK = TC + 273
= 37°C + 273
= 310. K
Solution