copyright 2013, 2010, 2007, pearson, education, inc. section 8.3 mass and temperature
TRANSCRIPT
Copyright 2013, 2010, 2007, Pearson, Education, Inc.
Section 8.3
Mass and Temperature
Copyright 2013, 2010, 2007, Pearson, Education, Inc.
What You Will Learn
How to determine which unit of mass is appropriateConverting between Celsius and Fahrenheit
8.3-2
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
Copyright 2013, 2010, 2007, Pearson, Education, Inc.
Gravitational PullThe 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
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
Copyright 2013, 2010, 2007, Pearson, Education, Inc.
Metric SystemThe 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
Copyright 2013, 2010, 2007, Pearson, Education, Inc.
Example 1: Choosing the Appropriate UnitDetermine which metric unit you would use to express the mass of the following.a) A 1-year-old child
Kilograms
b) A whaleMetric tonnes
8.3-7
Copyright 2013, 2010, 2007, Pearson, Education, Inc.
Example 1: Choosing the Appropriate Unitc) A pair of eyeglasses
Grams
d) A box of cerealGrams
e) A laptop computerGrams or kilograms
8.3-8
Copyright 2013, 2010, 2007, Pearson, Education, Inc.
Example 1: Choosing the Appropriate Unitf) A spider
Milligrams
g) A frogGrams
h) A refrigeratorKilograms
8.3-9
Copyright 2013, 2010, 2007, Pearson, Education, Inc.
Volume and Mass of WaterVolume in Cubic Units
1 m3 = 1 kl = 1 t (1000 kg)
1 dm3 = 1 l = 1 kg
1 cm3 = 1 ml = 1 g
Mass of Water
Volume in Liters
8.3-10
Copyright 2013, 2010, 2007, Pearson, Education, Inc.
Example 2: Volume of a Fish TankA 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
Copyright 2013, 2010, 2007, Pearson, Education, Inc.
Solutiona) Convert measurements to meters50 cm = 0.5 m, 250 mm = 0.25 m
V = l × w × h = 1 × 0.25 × 0.5 = 0.125 m3
Since 1 m3 of water = 1 kl of water,0.125 m3 = 0.125 kl, or 125 l of waterb) Since 1l = 1 kg, 125 l = 125 kgThe water in the fish tank has a mass of 125 kg.
Example 2: Volume of a Fish Tank
8.3-12
Copyright 2013, 2010, 2007, Pearson, Education, Inc.
TemperatureThe 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
Copyright 2013, 2010, 2007, Pearson, Education, Inc.
TemperatureSome common temperatures in both degrees Celsius (ºC) and degrees Fahrenheit.
Mild spring day68ºF20ºCWarm winter day50ºF10ºC
Freezing point of water
32ºF0ºCVery cold day0ºF–18ºCDescriptionºFºC
Temperature
8.3-14
Copyright 2013, 2010, 2007, Pearson, Education, Inc.
Temperature
Oven temperature for baking
351ºF177ºCBoiling point of water
212ºF100ºC
Body temperature98.6ºF37ºCWarm summer day86ºF30ºCDescriptionºFºC
Temperature
8.3-15
Copyright 2013, 2010, 2007, Pearson, Education, Inc.
Example 3: MetricTemperaturesChoose the best answer.
a) Chicago, Illinois, on New Year’s Day might have a temperature of
–10ºC 20ºC 45ºC
8.3-16
Copyright 2013, 2010, 2007, Pearson, Education, Inc.
Example 3: MetricTemperaturesChoose the best answer.
b) Washington, D.C., on July 4 might have a temperature of
15ºC 30ºC 40ºC
8.3-17
Copyright 2013, 2010, 2007, Pearson, Education, Inc.
Example 3: MetricTemperaturesChoose the best answer.
c) The oven temperature for baking a cake might be
60ºC 100ºC 175ºC
8.3-18
Copyright 2013, 2010, 2007, Pearson, Education, Inc.
Conversions
Celsius to Fahrenheit
Fahrenheitto Celsius
F
9
5C 32
C
5
9F 32
To convert from
8.3-19
Copyright 2013, 2010, 2007, Pearson, Education, Inc.
Example 4: Convert to ºCA typical setting for home thermostats is 72°F. What is the equivalent temperature on the Celsius thermometer?
SolutionSubstitute F = 72 into
C
5
9F 32
C
5
972 32
5
940 22.2º C
8.3-20
Copyright 2013, 2010, 2007, Pearson, Education, Inc.
Example 5: Convert to ºFIf the temperature outdoors is 28°C, what is the temperature in degrees Fahrenheit?
SolutionSubstitute F = 72 into
F
9
5C 32
F
9
528 32 50.432 82.4ºF
8.3-21