Chapter 6 Lessons 1 and 2. Thermal Energy Sum of the kinetic energy and the potential energy of...
-
Upload
beatrix-dixon -
Category
Documents
-
view
214 -
download
2
Transcript of Chapter 6 Lessons 1 and 2. Thermal Energy Sum of the kinetic energy and the potential energy of...
THERMAL ENERGY
TRANSFERSChapter 6 Lessons 1 and 2
THERMAL ENERGY AND TEMPERATURE Thermal Energy
Sum of the kinetic energy and the potential energy of the particles that make up a material
TemperatureAverage kinetic energy of the particles that
make up a material
THERMAL ENERGY AND TEMPERATURE CONTINUED Temperature and thermal energy are not
the same!Similar kinetic energy (ice melting)Different potential energy (distance
between particles)
HEAT Movement of thermal energy from a
warmer object to a cooler object
Heat and thermal energy are not the same.All objects have thermal energy.When you heat an object, thermal energy is
transferred.
HOW IS THERMAL
ENERGY TRANSFERRED?
Radiation, Conduction, Convection
RADIATION The transfer of thermal energy from one
material to another by electromagnetic wavesWarm objects: more radiationCan be transferred through solids, liquids,
and gasesOnly way thermal energy can travel from
Sun to EarthSpace is a vacuum.
RADIATION CONTINUED How does the Sun heat the inside of a
car?
Jumping Penny Demo
CONDUCTION Transfer of thermal energy between
materials by the collision of particles (contact)Continues until all particles in contact are
equal Thermal conductors
A material through which thermal energy flows easily Metals
Thermal insulatorsMaterial through which thermal energy does
not flow easily
CONDUCTION CONTINUED Specific Heat
The amount of thermal energy required to increase the temperature of 1 kg of material by 1C
Thermal conductors have a lower specific heat
Thermal insulators have a higher specific heat
Water has a high specific heat Prevents body from overheating Used to cool machinery Pools, oceans, lakes cool in summer
THERMAL EXPANSION AND CONTRACTION Thermal Expansion
An increase in a material’s volume when its temperature increases Particles speed up and move farther apart
Thermal ContractionA decrease in a material’s volume when its
temperature decreases Particles slow down and move closer together
Most noticeable in gases, less in liquids, and least in solids
THERMAL EXPANSION AND CONTRACTION CONTINUED Sidewalk Gaps
Too much expansion causes cracksControl joints cut for cracks
Hot Air BalloonsThermal Expansion – to riseThermal Contraction – to land
Ovenproof GlassExpands less than ordinary glass
CONVECTION Warm liquid moves from one place to
another, which transfers thermal energy Only occurs in fluids (water, air, magma,
syrup)
DENSITY, THERMAL EXPANSION, THERMAL CONTRACTION Heating water:
Burner transfers thermal energy to the container
Thermal expansion in water in the bottom makes it less dense
Water surface transfers thermal energy to air
Water on surface cools and contractsDense water sinks to the bottomLess dense water risesCycle continues
CONVECTION CURRENTS IN EARTH’S ATMOSPHERE Convection Current: movement of fluids in
a cycle because of convectionCirculates water on Earth, air in a room,
materials in Earth’s interior, Moves matter and thermal energy from inside
the Sun to its surface Move air between the equator and
latitudes 30N and 30S Earth’s climatesSun’s thermal energy is concentrated in this
areaHeat moves from warmer objects to cooler
objects