1. Copyright 2013, 2010, 2007, Pearson, Education, Inc. Section 8.3 Mass and Temperature

2. Copyright 2013, 2010, 2007, Pearson, Education, Inc. What You Will Learn How to determine which unit of mass is appropriate Converting between Celsius and Fahrenheit 8.3-2

3. Copyright 2013, 2010, 2007, Pearson, Education, Inc. Mass Although weight and mass are not the same, on Earth they are proportional to each other. Mass is a measure of the amount of matter in an object. It does not vary. Weight is the measure of gravitational pull on an object. It varies. 8.3-3

4. Copyright 2013, 2010, 2007, Pearson, Education, Inc. Gravitational Pull The gravitational pull of Earth is about six times as great as the gravitational pull of the moon. A person on the moon weighs about 1/6 as much as on Earth, even though the person’s mass remains the same. In space, where there is no gravity, a person has no weight but does have mass. 8.3-4

5. Copyright 2013, 2010, 2007, Pearson, Education, Inc. Metric System The kilogram is the basic unit of mass in the metric system. It is about 2.2 pounds. Kilogram is used to measure things that we normally measure in pounds. A man has a mass of about 75 kg. The gram is relatively small and used in place of the ounce. A nickel has the mass of about 5 g. 8.3-5

6. Copyright 2013, 2010, 2007, Pearson, Education, Inc. Metric System The milligram is used in the medical and scientific fields. Nearly all bottles of tablets are now labeled in either milligrams or grams. The metric tonne (t) is used to express mass of heavy items. One metric tonne equals 1000 kg. It is a little larger than our customary ton of 2000 lb. The mass of a large truck may be expressed in metric tonnes. 8.3-6

7. Copyright 2013, 2010, 2007, Pearson, Education, Inc. Example 1: Choosing the Appropriate Unit Determine which metric unit you would use to express the mass of the following. a)A 1-year-old child Kilograms b)A whale Metric tonnes 8.3-7

8. Copyright 2013, 2010, 2007, Pearson, Education, Inc. Example 1: Choosing the Appropriate Unit c)A pair of eyeglasses Grams d)A box of cereal Grams e)A laptop computer Grams or kilograms 8.3-8

9. Copyright 2013, 2010, 2007, Pearson, Education, Inc. Example 1: Choosing the Appropriate Unit f)A spider Milligrams g)A frog Grams h)A refrigerator Kilograms 8.3-9

10. Copyright 2013, 2010, 2007, Pearson, Education, Inc. Volume and Mass of Water Volume in Cubic Units 1 m 3 = 1 k l = 1 t (1000 kg) 1 dm 3 = 1 l = 1 kg 1 cm 3 = 1 m l = 1 g Mass of Water Volume in Liters 8.3-10

11. Copyright 2013, 2010, 2007, Pearson, Education, Inc. Example 2: Volume of a Fish Tank A fish tank is 1 m long, 50 cm high and 250 mm wide. a)Determine the number of liters that the tank holds. b)What is the mass of the water in kilograms? 8.3-11

12. Copyright 2013, 2010, 2007, Pearson, Education, Inc. Solution a) Convert measurements to meters 50 cm = 0.5 m, 250 mm = 0.25 m V = l × w × h = 1 × 0.25 × 0.5 = 0.125 m 3 Since 1 m 3 of water = 1 k l of water, 0.125 m 3 = 0.125 k l, or 125 l of water b) Since 1 l = 1 kg, 125 l = 125 kg The water in the fish tank has a mass of 125 kg. Example 2: Volume of a Fish Tank 8.3-12

13. Copyright 2013, 2010, 2007, Pearson, Education, Inc. Temperature The Celsius scale is used to measure temperatures in the metric system. The figure shows a thermometer with the Fahrenheit scale on the left and the Celsius scale on the right. On the Celsius scale, water freezes at 0ºC and boils at 100ºC. 8.3-13

14. Copyright 2013, 2010, 2007, Pearson, Education, Inc. Temperature Some common temperatures in both degrees Celsius (ºC) and degrees Fahrenheit. Mild spring day68ºF20ºC Warm winter day50ºF10ºC Freezing point of water 32ºF0ºC Very cold day0ºF–18ºC Description ºFºC Temperature 8.3-14

15. Copyright 2013, 2010, 2007, Pearson, Education, Inc. Temperature Oven temperature for baking 351ºF177ºC Boiling point of water212ºF100ºC Body temperature98.6ºF37ºC Warm summer day86ºF30ºC Description ºFºC Temperature 8.3-15

16. Copyright 2013, 2010, 2007, Pearson, Education, Inc. Example 3: Metric Temperatures Choose the best answer. a)Chicago, Illinois, on New Year’s Day might have a temperature of –10ºC 20ºC 45ºC 8.3-16

17. Copyright 2013, 2010, 2007, Pearson, Education, Inc. Example 3: Metric Temperatures Choose the best answer. b)Washington, D.C., on July 4 might have a temperature of 15ºC30ºC 40ºC 8.3-17

18. Copyright 2013, 2010, 2007, Pearson, Education, Inc. Example 3: Metric Temperatures Choose the best answer. c)The oven temperature for baking a cake might be 60ºC100ºC 175ºC 8.3-18

19. Copyright 2013, 2010, 2007, Pearson, Education, Inc. Conversions Celsius to Fahrenheit Fahrenheit to Celsius To convert from 8.3-19

20. Copyright 2013, 2010, 2007, Pearson, Education, Inc. Example 4: Convert to ºC A typical setting for home thermostats is 72°F. What is the equivalent temperature on the Celsius thermometer? Solution Substitute F = 72 into 8.3-20

21. Copyright 2013, 2010, 2007, Pearson, Education, Inc. Example 5: Convert to ºF If the temperature outdoors is 28°C, what is the temperature in degrees Fahrenheit? Solution Substitute F = 72 into 8.3-21