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