1A 2 2 HEATER A N D AIR C O N D I T I O N I N G
has already melted away-but the thermometer still reads
32°.
All this time, the ice has been soaking up heat, yet it
never gets any warmer no matter how much heat it
draws from the stored food. On the other hand, the cold
drain water got progressively warmer as it soaked up
heat. The addition of heat will make water warmer yet
won’t raise the temperature of ice above the 32° mark.
If we fill one drinking glass with ice and another with
cold water, and put both glasses in the same room where
they could absorb equal amounts of heat from the room
air, we will find it takes much, much longer for the ice to
melt and reach room temperature than it did for the
water in the other glass to reach the same temperature.
Obviously, most of the heat was being used to melt the
ice. But it was the heat that apparently disappeared or
was transformed because it couldn’t be located with a
thermometer. To describe this disappearing heat,
scientists chose the word "latent" which means hidden.
Latent Heat
So latent heat is nothing more nor less than hidden heat
which can’t be found with a thermometer.
At first it was thought that latent heat was in the water
that melted from the ice. But that wasn’t exactly the right
answer because, upon checking water temperature as it
melts from ice, it will be found that it is only a shade
warmer than the ice itself. It is not nearly warm enough
to account for all the heat the ice had absorbed. The only
possible answer is that the latent heat had been used up
to change the ice from a solid into a liquid.
Many substances can be either a solid, or a liquid, or a
gas. It just depends on the temperature whether water for
example was a liquid, or a solid (ice), or gas (steam) (fig.
28).
All solids soak up huge amounts of heat without getting
any warmer when they change into liquids, and the same
thing will happen when a substance changes from a
liquid into a gas.
Fig. 2 8 -T e m p e r a tu r e D e te r m in e s T h e S ta te O f W a te r
Put some water in a teakettle, set it over a fire and watch
the thermometer as the water gets hotter and hotter, the
mercury will keep rising until the water starts to boil.
Then the mercury seems to stick at the 212° mark. Put
more wood on the fire, despite all the increased heat, the
mercury will not budge above the 212° mark (fig. 29).
No matter how large or hot you make the flame, you
can’t make water any hotter than 212° at sea level. As a
liquid changes into a gas, it absorbs abnormally great
amounts of heat without getting any hotter.
Now we have two different kinds of latent heat, which
are quite a bit alike. To keep their identities separate,
the first one is called
latent heat of fusion,
which means
the same as melting. The other kind is called
latent heat
of vaporization
because that means the same as
evaporation.
Refrigeration
It may seem as though we have discussed heat instead of
Fig. 29--Boiling Water Never Exceeds 212° at Sea
Fig. 2 7 -M e ltin g Ice Remains at 32"
l_evel
LIGHT DUTY TRUCK SERVICE MANUAL
Summary of Contents for Light Duty Truck 1973
Page 1: ......
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Page 53: ...HEATER AND AIR CONDITIONING 1A 27 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 115: ...LIGHT DUTY TRUCK SERVICE M A N U A L HEATER AND AIR CONDITIONING 1A 89...
Page 123: ...BODY 1B 3 Fig 6 Typical 06 Van LIGHT DUTY TRUCK SERVICE MANUAL...
Page 149: ...BODY 1B 29 Fig 84 Body Mounting 06 Fig 85 Body Mounting 14 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 171: ...LIGHT DUTY TRUCK SERVICE M A N U A L Fig 2 Frame Horizontal Checking Typical FRAME 2 3...
Page 173: ...LIGHT DUTY TRUCK SERVICE M A N U A L Fig 4 10 30 Series Truck Frame FRAME 2 5...
Page 174: ...2 6 FRAME LIGHT DUTY TRUCK SERVICE MANUAL Fig 5 Underbody Reference Points G Van...
Page 185: ...FRONT SUSPENSION 3 11 Fig 16 Toe out on Turns LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 351: ...ENGINE 6 15 Fig ID Sectional View of Eight Cylinder Engine LIGHT DUTY TRUCK SERVICE MANUAL...
Page 375: ...EN G IN E 6 39 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 376: ...6 4 0 ENGINE LIGHT DUTY TRUCK SERVICE MANUAL...
Page 377: ...ENG IN E 6 41 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 378: ...LIGHT DUTY TRUCK SERVICE MANUAL Fig 37L K Series Engine Front Mount 6 42 ENG INE...
Page 400: ...6 6 4 ENG INE LIGHT DUTY TRUCK SERVICE MANUAL...
Page 401: ...ENG IN E 6 65 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 402: ...6 6 6 ENGINE LIGHT DUTY TRUCK SERVICE MANUAL...
Page 403: ...E NG IN E 6 67 Fig 36V C Series Engine Mounts LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 423: ...EN G IN E C OOLING 6K 13 Fig 16 Overheating Chart LIGHT DUTY TRUCK SERVICE MANUAL...
Page 424: ...6 K 1 4 ENG INE COOLING Fig 17 Coolant Loss Chart LIGHT DUTY TRUCK SERVICE MANUAL...
Page 456: ...6M 32 ENGINE FUEL Fig K15 Accelerator Controls G Van L 6 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 492: ......
Page 512: ...Fig 18e Vacuum Advance Diagram V8 Engine...
Page 516: ...6 T 2 4 E M IS S IO N CONTROL SYSTEMS LIGHT DUTY TRUCK SERVICE MANUAL...
Page 528: ......
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Page 593: ...CLUTCHES MANUAL TRANSMISSIONS 7M 3 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 598: ...7M 8 CLUTCHES MANUAL TRANSMISSIONS LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 743: ...FUEL TANKS AND EXHAUST 8 13 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 744: ...8 14 FUEL TANKS AND EXHAUST LIGHT DUTY TRUCK SERVICE MANUAL...
Page 760: ...8 30 FUEL TANKS AND EXHAUST Fig 40 Exhaust Pipe P Models LIGHT DUTY TRUCK SERVICE MANUAL...
Page 761: ...FUEL TANKS AND EXHAUST 8 31 LIGHT DUTY TRUCK SERVICE MANUAL...
Page 763: ...FUEL TANKS AND EXHAUST 8 33 LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 832: ...LIGHT DUTY TRUCK SERVICE MANUAL Fig 106 Power Steering Pump Mounting Typical 9 66 STEERING...
Page 833: ...PUMP ASSEMBLY STEERING GEAR TYPICAL SMALL V8 TYPICAL LARGE V8 STEERING 9 67...
Page 861: ...STEERING 9 95 Fig 134 Power Steering Pump Leakage LIGHT DUTY TRUCK SERVICE MANUAL...
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Page 886: ...11 10 CHASSIS SHEET METAL LIGHT DUTY TRUCK SERVICE MANUAL...
Page 891: ...ELECTRICAL BODY AND CHASSIS 12 5 LIGHT DUTY TRUCK SERVICE MANUAL...
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