Thermal EnergyThermal Energy
TemperatureTemperatureMeasures the “hotness” (higher
temperatures) or “coldness” (lower temperatures)
Gives very little information on the energy that the material contains.
Temperature HeatTemperature Heat
Some equate temperature to heat
Temperature and Heat are not the same
TemperatureTemperatureAll matter is made up of tiny
particlesThese tiny particles are
constantly moving
All moving things have kinetic energy
The faster the particles move the more KE
The temperature is a measure of the average Kinetic Energy
Thermal EnergyThermal EnergyPlace a ice-cold spoon on ice cream.
What happens?Place a hot spoon on ice cream. What
happens?
Place two hot spoons on ice cream. How is it different?
Pour hot water on the ice cream. How is this different from the spoon?
Thermal EnergyThermal EnergyThermal energy is the total
amount of kinetic and potential energy of a material
Kinetic energy determined by the speed of the moving particles
Potential energy determined by the distance between the particles
Thermal Energy & TemperatureThermal Energy & Temperature
They are relatedAs temperature increase so does the
kinetic energy and the potential energy of the particles
Thermal EnergyThermal Energy
Depends upon temperatureMass of materialType of material
HeatHeat
The transfer of thermal energy
HeatHeatHeat is the energy that flows
from an object of higher temperature to an object with lower temperature
Heat is measured in units of Joules
Does an ice cube in warm water cause the water to cool down
Or does the warm water cause the ice cube to melt?
So…
Specific HeatSpecific Heat
Why is the air around the swimming pool warmer than the water even if they have both been exposed to the sun the same amount of time?
Different materials need different amounts of heat to change the temperature the same amount.
Copper pot –vs- water
Specific Heat is the amount of heat necessary to raise the temperature of one kilogram of a material one degree Celsius
Units (J/kg.Co)Specific heat of water very
highAdvantages?Disadvantages?
Measuring Specific HeatMeasuring Specific Heat
Cannot measure the amount of heat energy transferred
Can only measure the resultant change in thermal energy
Q = mcTm-mass in grams or kilogramsQ- thermal energy in Joulesc-specific heat in J/kg.Co or
J/g.Co
T-change in temperature in Co
Change in LengthChange in LengthWhen temperature is
increased objects expandSidewalks, siding on
houses, railroad tracks, bridges, etc…
l=lTl-change in lengthl-original lengthcoefficient of linear
expansionT-change in temperature
Change in VolumeChange in VolumeLiquids expand 100 times
more than solidsV=VT
V-change in volumeV-original volumecoefficient of volume
expansionT-change in temperature
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