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2. Heat. Calories. Temperature. Celsius. Thermometer. Specific Heat. Fahrenheit. Absolute Zero. Temperature. Temperature is a measure of how hot or cold an object is. Ice Water. 0 o C. 32 o F. 273 o K. 212 o F. 373 o K. Boiling Water. 100 o C. 310 o K. 37 o C. 99 o F. - PowerPoint PPT Presentation
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TemperatureTemperatureTemperature is a measure of how hot or cold an object is
Ice Water 0o C 32o F 273o K
Boiling Water 100o C 212o F 373o K
Room Temp 20o C 68o F 293o KBody Temp 37o C 99o F 310o K
Absolute Zero -273o C -459o F 0o K
F = 9/5 C + 32 K = C + 273
Pressure and TemperaturePressure and Temperature
Boiling WaterIce Water
Pressure Gage
Constant Air Volume
0o C
Pressure Decreases
Pressure Increases
Absolute ZeroAbsolute Zero
Ice Water 273o K
Boiling Water 373o K
Absolute Zero
0o K
Temperature (o C)
0o C
-273o C
Quantity of HeatQuantity of HeatQuantity of Heat = Mass x Specific Heat x Temperature Change
Q = m c ΔT1 calorie is the amount of heat energy necessary to
raise 1 gram of water 1 celsius degree.
Specific Heat (Capacity) is the amount of heat energy necessary to raise 1 gram of a substance 1 celsius degree.
1 calorie = 4.18 joules
1 Calorie = 1,000 calories = 4,180 joules
Calorimetry
Hot Object Cold Object
Heat Loss = Heat Gain
mH cHΔTH = mC cCΔTC
Heat Flow
mH = mass of hot object
cH = specific heat of hot object
ΔTH = temperature change of hot object
mC = mass of cold object
cC = specific heat of cold object
ΔTC = temperature change of cold object
Sample Problem 1
mH = 500 g
TH = 90.0oC
CH = .30 cal/goC
mC = 200 g
TC = 10.0oC
CC = 1.0 cal/goC
TE = ?
Heat Loss = Heat Gain
mH cHΔTH = mC cCΔTC
500(.30)(90- TE) = 200(1.0)(TE - 10)
150 (90- TE) = 200 (TE - 10)
13500- 150TE = 200 TE - 2000
350TE = 15,500
TE = 44.3 oC
Hot Object Cold Object
Heat Flow
500 g of metal at 90.0o C is placed in 200 g of water at 10.0o C.The specific heat capacity of the metal is .30 cal/goC. What is the final equilibrium temperature of the water and metal?
Sample Problem 2
mH = 800 g
TH = 100.0oC
mC = 200 g
TC = 10.0oC
TE = 40.0oC
CC = 1.00 cal/goC
CH = __ cal/goC
Heat Loss = Heat Gain
mH cHΔTH = mC cCΔTC
800 (CH)(100- 40) = 200(1.0)(40 - 10)
48,000 (CH) = 6,000
CH = .125 cal/goC
Cold WaterHot Metal
800 g of metal at 100.0o C is placed in 200 g of water at 10.0o C. The final equilibrium temperature of the water plus metal is 40.0oC. What is the specific heat capacity of the metal ?
Thermal Expansion
Linear Expansion
Lo ΔL
ΔL = is proportional to ΔT
ΔL = is proportional to Lo
ΔL = depends on the type of material
Volume Expansion
ΔV = is proportional to ΔT
ΔV = is proportional to Vo
ΔV = depends on the type of material
Linear Expansion
1. Aluminum 2.4 cm per km
2. Brass 2.0 cm per km
3. Copper 1.7 cm per km
4. Steel 1.2 cm per km
5. Glass 0.4-0.9 cm per km
The following materials are listed in alphabetical order. Arrange them in order of their rate of linear expansion per oC from lowest to highest.
AluminumBrassCopperGlassSteel
Expansion of Water
Conductivity
TH TCH
L
H increases as (TH – TC) increases
H = depends on the type of material
H decreases as L increases
H is the heat flow between hot (TH) and cold ( TC) objects
Top 7 Conductors of Heat1. Silver 406
2. Copper 385
3. Aluminum 205
4. Brass 109
5. Steel 50
6. Lead 35
7. Mercury 8
Aluminum Brass Copper Lead Mercury SilverSteel
The following metals are listed in alphabetical order. Arrange them in order of conductivity from best to worst.
Top 10 Heat Insulators 1. Styrofoam .012. Air .0243. Cork .044. Felt .045. Fiberglass .046. Rock Wool .047. Wood .128. Brick .69. Concrete .810. Glass .9
Air BrickConcrete Cork Felt FiberglassGlassRock WoolStyrofoamWood
The following insulators are listed in alphabetical order. Arrange them in order of insulation from best to worst.
Sea Breezes and Convection Currents
Day
During the day, the land is hotter and the air rises above the land and is replaced by the cooler air
from above the water.
During the night, the land cools faster and the air rises above the warmer water and is replaced by the
cooler air from above the land.
Night
Convection Currents and the Earth
RadiationRadiation
• A good radiator of heat is a good absorber of heat.
• Dark colored objects radiate and absorb heat better than light colored objects.
• The rate of heat radiation increases with temperature.
• The rate of heat radiation or absorption is proportional to the surface area of the object radiating or absorbing.
Scaling and Heat Radiation
S = 1 cm
S= 10 cm
S = 2 cmV= 8 cm3
A = 24 cm2
V= 1 cm3
A= 6 cm2
V= 1000 cm3
A = 600 cm2
A/V = 6
A/V = .6
A/V = 3
2
Ice WaterSteam
Heat Heat
80 calories added to 1 g of ice at 0oC will convert the ice to 1gram of water at 0oC.
540 calories added to 1 g of water at 100oC will convert the water to 1gram of steam at 100oC.
Change of State
3
Change of Phase
-40
-20
0
20
40
60
80
100
120
140
0 20 40 60 80 100
time
Deg
rees
Cel
sius
Series1
Water to Steam
Ice to Water
Water
Ice
Steam
The Human Body -Thermodynamic System
External Work
Internal Work
Food
Heat OutHeat In
Energy Change = (Food +Heat In) – (External Work + Heat Out + Internal Work)
Thermodynamics and Weight Loss
External Work
Internal Work
Food
Heat OutHeat In
Energy Change = Food + Heat In – External Work - Heat Out - Internal Work
If Energy Change > 0, then you gain weight. If Energy Change < 0, then you lose weight.
If 1 once fat is equivalent to approximately 300 Calories of energy, we can calculate weight loss on a daily or monthly basis based on ΔU value.
If Energy Change = 0, then you maintain your body weight.