Transcript The Prime Movers - Pleasant Grove Middle School

The Prime Movers
Temperature in Thermal Systems
I. Thermal Energy
 The total energy of the thermal
motion of all the particles that
make up an object
II. Temperature
A. “hotness”
B. The average kinetic energy of the
random motion of the atoms and
molecules in a body
III. Measuring Temperature
A. Thermometer—uses expansion
and contraction of a liquid to
measure temperature
B. Thermal equilibrium—when
temperatures become equal because
of energy flow from a substance
with higher temp. to a substance
with lower temp.
C. Celsius—freezing point of water
is 0°C; boiling point is 100°C
D. Fahrenheit--freezing point of
water is 32°F; boiling point is 212°F
E. TC = 5/9 (TF-32)
F. TF = 9/5 TC +32
IV. Heat
A. Conduction—thermal energy
flows from hotter object to cooler
object by colliding particles—
TOUCH
B. Heat—energy that flows because
of a temperature difference
C. Temperature Difference is the
prime mover in thermal systems
V. Specific Heat
A. Units
1. joule—SI
2. calorie—amount of thermal
energy it takes to change the temp.
of 1g of water by 1° C
3. Btu—amount of thermal
energy it takes to change the temp.
of 1 lb of water by 1° F
B. Specific heat—amount
of energy that must be
added to raise the temp of
a unit mass of the
substance one temp.
unit—based on water as 1
1. Q = mCΔT
2. transferred heat =
mass x specific heat x
change in temp
C. Change of State
1. boiling point—temp needed
to change a liquid to a gas
2. heat of fusion—amount of
energy needed to melt one gram of a
solid
3. heat of vaporization—the
amount of energy needed to
vaporize one gram of a liquid
4. Q = mHf—amount of heat
needed to melt a solid
heat = mass x heat of fusion
5. Q = mHv—amount of heat
needed to vaporize a liquid
heat = mass x heat of vaporization