great lakes heat source heat sink
TRANSCRIPT
Heat Source Heat Sink Great Lakes Rocks
Teacher Education CourseSchool Year 2016-2017
Vocabulary PreviewTemperatureEnergy
•Heat• Internal Energy (thermal energy)
Heat Transfer Methods•Conduction•Convection•Radiation
Specific Heat Heat Capacity
UnitsTemperatur
e• Celsius• Kelvin • Fahrenheit
Energy• Joules• calories
Mass• kilograms
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When the substance is the same, what is the relationship between temperature, mass, and total energy?
When the substance is the same, what is the relationship between temperature, mass, and total energy?
One beaker holds twice as much water by mass as the other. Each has identical Bunsen burners providing equal heat energy flow per second.
Which reaches 100 degrees Celsius first?
What would could you say about the change in thermal energy of each beaker at the moment when first one reaches 100 degrees Celsius?
When the substance is the same, what is the relationship between temperature, mass, and total energy?
One beaker holds twice as much water by mass as the other. Each has identical Bunsen burners providing equal heat energy flow per second.
How much more energy is required to get the larger beaker to 100 C compared to the energy to do so for the smaller beaker?
When the substances are NOT the same, what is the relationship between temperature, mass, and total energy?
50 g of Water 50 g of Water 50 g of Water 50 g of Sand
20 C 20 C80 C80 C
50 C 30 C
When the substances are NOT the same, what is the relationship between temperature, mass, and total energy?
50 g of Water 50 g of Sand
Liquid water has 5 times the capacity to absorb heat and produce same temperature change as same mass of sand
When the substances are NOT the same, what is the relationship between temperature, mass, and total energy?
50 g of Water 50 g of Sand
Liquid water has 5 times the capacity to give off heat and produce same temperature change as same mass of sand
Water Sand
Mass Specific Heat (J/g·C°)
Heat Capacity (J/C°)
Specific Heat (J/g·C°)
Heat Capacity (J/C°)
10 g 4.2 42 0.84 8.420 g 4.2 84 0.84 16.850 g 4.2 210 0.84 42
100 g 4.2 420 0.84 84200 g 4.2 840 0.84 168
The specific heat of water is always ~ 5 times greater than the specific heat of sand, independent of the mass of the sample, because specific heat is an intensive property of a substance.
The heat capacity of a sample of water depends on the mass of the sample, making it an extensive property. A beaker with 20 g of water has twice the heat capacity of a beaker with 10 g of water (but the water in each beaker has the same specific heat value). It would take a beaker with 50 g of sand to have the same heat capacity as 10 g of water.
Heat Transfer: Electromagnetic Radiation (~light)
Heat Always Flows from
Higher Temperature to
Lower Temperature (Natural System)
Color is a major variable (emissivity)
Good absorbers (dark) are good
emitters.
Heat Transfer: Conduction (~direct contact)
Heat Always Flows from
Higher Temperature to
Lower Temperature (Natural System)
Some materials conduct quickly
(metal) and others conduct slowly
(wood).
Heat Transfer: Convection (~moving fluids)
Heat Always Flows from
Higher Temperature to
Lower Temperature (Natural System)
Changes in density due to temperature difference, along
with gravity, cause natural movement of
liquids and gases
energy gets “carried along” and “dropped
off”
In this case, the pool of water is a heat sink for the grill
In this case, the pool of water is a heat source for the ice cream
How does the proximity of the Lake affect the air temperature?
Temperature on July 1, 2008
Benton Harbor, MI
17.3 C
South Bend, IN
18.5 C
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 310
5
10
15
20
25
30
Air temperaturesLake Michigan, July
Benton Harbor, MI
South Bend, IN
Date
Tem
pera
ture
s (d
egre
es C
elsu
is)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
-20
-15
-10
-5
0
5
10
15
20
Air temperaturesLake Michigan, January
Benton Harbor, MI
South Bend, IN
Date
Tem
pera
ture
s (d
egre
es C
elsu
is)
