Energy And Temperature

Chapter 6 Energy and States of Matter Energy Measuring Temperature

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Energy • Makes objects move • Makes things stop • Energy from sun eat

plants

foods we

energy to live

• We need energy to “do work” LecturePLUS Timberlake

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Work is done when Go up stairs Play soccer Lift a bag of groceries Ride a bicycle Breathe Heart pumps blood Water goes over a dam LecturePLUS Timberlake

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Potential Energy Is stored energy Examples  Water behind a dam  Compressed spring  Chemical bonds in gasoline or coal  Food LecturePLUS Timberlake

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Kinetic Energy Is energy of motion Examples

Hammering a nail Water flowing over a dam Working out Boxing Burning gasoline LecturePLUS Timberlake

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Some Forms of Energy Mechanical Electrical Thermal (heat) Chemical Radiant (light) LecturePLUS Timberlake

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Learning Check E1 A. A car uses more fuel when the air conditioner is on. True (1) or False (2) B. An apple hanging on a tree has potential energy that can turn into both mechanical or chemical energy. True (1) or False (2)

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Solution E1 A. A car uses more fuel when the air conditioner is on. True (1) B. An apple hanging on a tree has potential energy that can turn into both mechanical or chemical energy. True(1)

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Temperature Particles are always moving. When you heat water, the water molecules move faster. When molecules move faster, the substance gets hotter. When a substance gets hotter, its temperature goes up. LecturePLUS Timberlake

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Learning Check E2 Suppose you place water in a freezer. A. The water particles move 1) faster

2) slower

3) the same

B. The water will get 1) hotter

2) colder

3) stay the same

C. The temperature of the water will be 1) higher

2) lower LecturePLUS Timberlake

3) the same 10

Solution E2 Suppose you place water in a freezer. A. The water particles move 2) slower B. The water will get 2) colder C. The temperature of the water will be 2) lower LecturePLUS Timberlake

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Temperature Measures the hotness or coldness of an object Determined by using a thermometer that contains a liquid that expands with heat and contracts with cooling.

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Temperature Scales

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Temperature Scales Fahrenheit Water boils

Celsius Kelvin

212°F

100°C

373 K

Water freezes 32°F

0°C

273 K

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Units of Temperature between Boiling and Freezing Fahrenheit Water boils

212°F

180° Water freezes 32°F

Celsius Kelvin 100°C 100°C

373 K 100K

0°C

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273 K

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Learning Check E3 A. Temperature of freezing water 1) 0°F 2) 0°C 3) 0 K B. Temperature of boiling water 1) 100°F 2) 32°F 3) 373K C. Number of Celsius units between the boiling and freezing points of water 1) 100 2) 180 3) 273 LecturePLUS Timberlake

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Solution E3 A. Temperature of freezing water 2) 0°C B. Temperature of boiling water 3) 373K C. Number of Celsius units between the boiling and freezing points of water 1) 100 LecturePLUS Timberlake

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Fahrenheit Formula 180°F 100°C

=

Zero point:

9°F 5°C

=

1.8°F 1°C

0°C = 32°F

°F

= 9/5 T°C + 32

°F

= 1.8 T°C + 32

or

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Celsius Formula Rearrange to find T°C °F

=

1.8 T°C + 32

°F - 32

=

1.8T°C ( +32 - 32)

°F - 32

=

1.8 T°C

1.8 °F - 32

1.8 =

T°C

1.8 LecturePLUS Timberlake

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Temperature Conversions A person with hypothermia has a body temperature of 29.1°C. What is the body temperature in °F? °F = 1.8 (29.1°C) + 32 exact

tenth's

=

52.4 + 32

=

84.4°F

exact

tenth’s LecturePLUS Timberlake

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Learning Check E4 The normal temperature of a chickadee is 105.8°F. What is that temperature in °C? 1) 73.8 °C 2) 58.8 °C 3) 41.0 °C

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Solution E4 3) 41.0 °C Solution: °C = = =

(°F - 32) 1.8 (105.8 - 32) 1.8 73.8°F 1.8° LecturePLUS Timberlake

=

41.0°C 22

Learning Check E5 Pizza is baked at 455°F. What is that in °C? 1) 437 °C 2) 235°C 3) 221°C

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Solution E5 Pizza is baked at 455°F. What is that in °C? 2) 235°C (455 - 32) = 235°C 1.8

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Learning Check E6 On a cold winter day, the temperature falls to -15°C. What is that temperature in °F? 1) 19 °F 2) 59°F 3) 5°F

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Solution E6 3) 5°F Solution: °F = 1.8(-15°C) + 32 = -27 + 32 = 5°F

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Kelvin Scale On the Kelvin Scale 1K

=

1°C

0 K is the lowest temperature 0K K K =

= - 273°C °C °C + 273 LecturePLUS Timberlake

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Learning Check E7 What is normal body temperature of 37°C in kelvins? 1) 236 K 2) 310 K 3) 342 K

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Solution E7 What is normal body temperature of 37°C in kelvins? 2) 310 K K

= = =

°C + 273 37 °C + 273 310. K LecturePLUS Timberlake

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