Transcript POWERPOINT SCIENCE

THERMAL ENERGY
AND HEAT
Jennefer Cardenas
Objectives
Students will be able to identify and know
difference between THERMAL ENERGY,
TEMPERATURE, and HEAT.
Students will be able to identify the 3 ways
heat is transferred.
Students will be able to compare different
conductors and insulators.
Students will be able to compare Celsius
and Fahrenheit Scale.
TEMPERATURE
 The measure of the average kinetic energy of
the individual particles in an object.
 Matter is made up of tiny particles called atoms
and molecules. These particles are always in
motion even if the object they make up isn’t
moving at all. Energy of motion is called kinetic
energy, so all particles of matter have kinetic
energy. The faster the particles are moving, the
more kinetic energy they have.
WATER AND DYE EXPERIMENT
Why did the dye in hot water move faster
than the dye in cold water?
The results have to do with the different
temperatures of the water.
Back to Experiment
So what explanation would be given if we
heated the cold water.
Its particles will start moving faster, so their
kinetic energy will increase. This means that
the temperature of the water will rise.
THERMAL ENERGY
The total energy of all the particles.
If 2 samples of matter are at the same
temperature they do not necessarily have
the same total energy.
What is Heat?
How is heat transferred?
Heat is thermal energy moving from a
warmer object to a cooler object.
There are 3 ways that heat can move.
Conduction
Convection
Radiation
CONDUCTION
Heat conduction or thermal conduction
is the transfer of thermal energy through
matter, from a region of higher
temperature to a region of lower
temperature, and acts to equalize
temperature differences.
It is also described as heat energy
transferred from one material to another
by direct contact.
CONVECTION
Convection is the movement of molecules
within fluids ( a liquid or a gas); the warm
fluid rises and cooler fluids flow in to
replace it. This creates a circular flow.
More Convection
 The wind we feel outside is
often the result of convection
currents. You can understand
this by the winds you feel near
an ocean. Warm air is lighter
than cold air and so it rises.
During the daytime, cool air
over water moves to replace
the air rising up as the land
warms the air over it. During
the nighttime, the directions
change -- the surface of the
water is sometimes warmer
and the land is cooler.
RADIATION
The transfer of energy by electromagnetic
waves.
Radiation does not require matter to
transfer thermal energy.
Radiation
 The sun's rays travel in
straight lines called heat
rays. When it moves that
way, it is called radiation.
 When sunlight hits the
earth, its radiation is
absorbed or reflected.
Conductors and insulators
A conductor is an object that can conduct
heat well
An insulator is an object that conducts
heat poorly.
ASSESMENT
 What are the 3 ways heat is transferred
 Convection, Conduction, and Radiation
 TRUE or FALSE The transfer of energy by electromagnetic waves is
the definition for Convection
 False
 TRUE or FALSE In this picture “B” is representing a heat conductor
and “A” is representing heat convection?
 True