Download Thermal Energy - Issaquah Connect

Thermal
Energy
Heat & Temperature
Definitions
 Energy

Can do work
 Kinetic

Energy
Energy associated with the motion of objects,
large or small
 Thermal

Energy
Kinetic energy of microscopic particles that
make up all matter
Definitions

Heat



Total amount of thermal
energy an object possesses
Flows from warmer to
cooler objects
(“Thermal energy in
transit”)
Temperature

Average thermal energy of
the molecules in a
substance
Definitions
Obj A: Thermal Energy
Obj A:
Temperature
Obj B: Thermal Energy
Obj B:
Temperature
Heat: Energy Units
 Calorie
– amount of heat needed to
change the temperature of 1 gram of
water 1 ̊ C.
 Joule
 NOTE:
– (1 calorie = 4.18 joules)
Food calories
Temperature Scales
Celsius ( ̊ C ): Our unit of choice
 Kelvin ( K ): Based on “absolute
zero”
 Farenheit ( ̊ F ): Silly imperial unit

Temperature Scales
Celsius
(̊C)
Kelvin
(K)
Farenheit
(̊F)
Water Boils
100
373
212
Water Freezes
0
273
32
“Absolute
Zero”
-275
0
-459
Room
Temperature
20
293
68
Specific Heat Capacity
 Quantity
of heat required to change the
temperature of a unit mass of the
substance by one degree.
 Measure
of a substance’s ability to “store”
thermal energy.
Laws of Thermodynamics
 Whenever
heat flows into or out of a
system, the gain or loss of thermal energy
equals the amount of heat transferred.
 Heat
never spontaneously flows from a
cold substance to a hot substance.
 No
system can reach absolute zero.
Kinetic Molecular Theory
 All
matter is made up of tiny particles.
 These
particles are in constant motion.
 Increasing
the motion of the particles
increases temperature.
Thermal Expansion



As a substance is heated (thermal energy is increased),
particles move faster and farther apart.
Liquids expand more than solids with increases in
temperature.
Gases expand more than liquids with increases in
temperature.
Definitions

Kinetic energy is a general term describing the energy
associated with the motion of objects (large or small
objects). You can calculate the kinetic energy of an object
of mass m with a velocity (speed) v from the formula K.E. =
1/2 mv^2. Thermal energy refers to the kinetic energy of the
microscopic particles (atoms and molecules) that make up
all samples of matter - i.e. all objects. When you add heat
to an object, you increase the temperature of the object
(usually) and that heat increases the kinetic energy of the
molecules that comprise that object. In fact, temperature is
a measure of the average kinetic energy of the
microscopic particles that make up an object.