Chapter 8 – Energy Transfer and Conservation
IntroductionWhat does “transfer” mean?
Movement of energy from one place to another without a change in form
What does “transformation” mean?Process changing from one form of energy to
anotherAre they the same thing?
KEY QUESTION
How does the transfer of energy affect natural and
human-built environment?
Natural vs. Human-BuiltHow do natural environments differ from
human-built environments?Natural environments are living and non-living
things that occur naturally; human-built environments have been invented and built by people
Natural and Human-MadeWhat are some examples of things and
processes that occur in our natural environment?Oceans, mountains, the wind, water, sunlight,
etc.What are some examples of things and
processes that that are human-built?Bridges, cars, coffee cups, etc.
8.1 Thermal Energy TransferWhat is the definition of thermal energy?Thermal Energy: the total kinetic energy and
energy of attraction of all the particles of a materialwe can increase the thermal energy of a
substance by heating it We can decrease the thermal energy of a
substance by cooling itChanges in thermal energy can cause a
substance to change states (solid to liquid, etc.)
What if…?What would life be like if we didn’t have
refrigerators, air conditioners, and heaters?
Read page 203
8.3 ConductionFigure 1 on page 206What is happening? Explain.
ConductionConduction: the transfer of thermal energy
through a substance, or between substances in contact, by the collision of particlesParticles must collide in order for thermal
energy to be transferred by conduction
Question…Can conduction occur between two objects
that are not touching or connected in some way?No…conduction can only occur between two
objects or substances that are touching.
Read page 206 and 207
8.4 Conduction and Geological Processes
Trivia: What is the Earth made up of?The mantle is almost entirely solid rock. It
contains a small amount of molten rock, but the vast majority is solid.
What does “geological” mean?Having to do with the Earth and rocks
How might conduction effect geological processes?
Geothermal EnergyGeothermal Energy: is energy contained
below the Earth’s surface
Read top of page 208
Volcanic EruptionsThe volcanic eruptions that cause hot magma
to be pushed to Earth’s surface are not caused by conduction; the magma rises toward the surface because it is less dense than the surrounding rock.
Magma is often under pressure because it is in tight spaces when it is heated.
Magma and lava lose a lot of thermal energy through conduction into the surrounding rocks or air.
Heat and Rock FormationIgneous rock: rock formed from magma that
has cooled and solidified
Metamorphic rock: rock that is formed when heat and pressure change existing rock
Heat and Rock FormationOnce the rock is exposed to high temperature
and pressure, thermal energy is transferred to the rock by conduction
This causes the particles of the rock to be rearranged, resulting in the formation of metamorphic rock, including diamonds
DiamondsForm deep in the Earth’s crustHeat and pressure may change substances
into diamondMetamorphic rock
8.5 ConvectionConvection: the transfer of thermal energy
from one part of a fluid to another by circulating current of faster-moving and slower-moving particlesConvection occurs in a fluid whenever warmer
fluid exists below cooler fluid.Heating fluid from below causes convection
because it produces an area of warm fluid at the nottom of an area of cooler fluid.
Steps to heating a pot of soup on the stove…
Groups of 3 or 4Arrange the steps in the correct order
Figure 1 on page 210…What is happening when this pot of soup is
heated?
Read page 210 and 211
8.6 Convection in the EnvironmentWhat did you notice during the last
thunderstorm we had/you remember?What were the conditions before the storm?Why do thunderstorms happen?
Occur largely because of the effects of convection in the atmosphere
Change in temperatures
What is convection and conduction?Convection: the transfer of thermal energy
from one part of a fluid to another by circulating current of faster-moving and slower-moving particles
Conduction: the transfer of thermal energy through a substance, or between substances in contact, by the collision of particles
ThunderstormsThunder and lighteningCan lead to hail, tornados, and hurricanes
The Earth’s surface is heated by the sunEnergy is transferred to the air by conductionThe warm air is pushed up higherLarge puffy clouds appearA lot of thermal energy released
Read top of page 213
8.7 RadiationWhat is our major source of energy?
The SunConduction and convection can only occur
when matter is presentIn this section, we will learn about the third
type of energy transfer that does not require the presence of matter
Energy TransferRadiant Energy: energy that travels in the
form of electromagnetic waves through empty space; includes visible light, ultraviolet rays, and infrared rays
Radiation: the transfer of radiant energy by means of electromagnetic waves
Hair straightener activityRead page 214 and 215
UV Rays
What colour attracts the sun?
8.8 Managing the Transfer of Thermal EnergyWhat are the three methods of energy
transfer?Conduction – transfers thermal energy through
wallsConvection – currents produced by heaters
warm the roomsRadiation – from the Sun; energy can be
transferred to roofs through electromagnetic rays
Our School
What are some components of the school that work together to transfer energy throughout the school? Walls, roof, lights, air vents, floors, windows, doors, custodians,
etc.
What happens when a building is poorly designed?Some areas may be really hot and some may be very
coldExpensive to heat because of poor insulation
Read page 217
Thermal Energy TransferWhat are ways we can reduce thermal energy
transfer?Caulking gapsReplace old furnacesClosing blinds on sunny daysOpen windows at night to bring in cooler air
Preventing ConductionUse insulating materialsThe higher the R-Value, the more difficult it
is for energy to move through the material
Insulation material R-Value(2.5 cm thick) wood 0.71–1.41fibreglass batt 3.2–3.6cellulose 3.1–3.7polystyrene foam 3.6-5.0board
Green Roofs10% reduction in heat costs during the winter25% saving in air conditioning costs in the
summer
Read page 218 - 220