Insulation
Learning objectives:
Key Vocabulary:
Radiation
Surface area
Thermal
Insulation
Radiation
emit
Absorb
Efficiency
Starter 1
How can heat be transferred?
(hint 3 different ways)
Starter 2
What is an insulator and a conductor? Name an example of each?
Starter 3
Challenge: Draw the Sankey diagram to represent 100% electrical energy input into a light bulb with 10% used for light.
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
Insulation
Learning objectives:
Starter 1
Convection,
Conduction radiation
Starter 2
Insulator does not allow heat to flow through,
Conductor allows heat to flow
Starter 3:
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
Keeping things warm
What other scientific principle is this similar to?
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
A temperature problem
Touch a metal object. Touch a plastic /wooden object. Which feels colder and why? Is one actually colder?
The metal feels cold and the wood feels warm.
Metal is a good conductor and conducts the heat away from your hands, so it feels cold.
Wood is not a good conductor and does not conduct the heat away from your hands as well as the metal, so the wood feels warmer than the metal.
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
What are thermal insulators?
This is how your clothes keep you warm – air is trapped between the fibres and so acts as an insulator.
Some materials are very poor conductors of heat. These are called thermal insulators.
Other insulating materials, including polystyrene(foam) and fiberglass, use trapped air because it is so effective.
Examples of materials that are insulators include plastics, wood, ceramics and air.
Air becomes a very effective insulator when it is trapped and stopped from moving.
Where might this be used?
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
Pair Work Instructions (a different colour pen should be used for these steps)
How can heat loss through a roof be reduced?
How can heat loss through windows be reduced?
How can heat loss through a door be reduced?
How can heat loss through walls be reduced?
How can heat loss from radiators be reduced?
Challenge: How does a vacuum flask work? Mention as many specific parts of the flask as you can.
How can curtains reduce heat loss?
1)Divide the questions between each person
2)Attempt the question with your own knowledge,
3)Confer with your partner
4)Research your question
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
How does a vacuum flask work?
How is a vacuum flask able to keep hot drinks hot and cold drinks cold?
2. The plastic (or cork) lid is an insulator and the screw top prevents convection currents escaping from the flask.
1. There is a vacuum between two layers of glass or steel, which prevents heat leaving or entering by conduction.
3. The walls have silvery surfaces, which prevent heat leaving or
entering by radiation.
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
17-11-2021
part of flask | processes reduced (eg ‘conduction’) |
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Write down the ways in which a vacuum flask reduces heat transfer
outer cap / cup
conduction & convection
plastic cap
convection & conduction
shiny mirror surfaces
radiation
vacuum
conduction & convection
sponge
conduction
air
conduction
plastic case
conduction
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
Heat loss from houses
A thermogram shows the distribution of heat over the surface of a house. It highlights where heat is being lost.
The white, yellow and
red areas are the warmest, so these are
the worst insulated
parts of the house.
A poorly insulated house loses more energy and so costs more to heat. It also means that more pollution, particularly carbon dioxide, is created in order to heat the house.
The blue and green areas are the coolest, so these are the best insulated parts of the house.
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
Heat loss from houses
Where is the most heat lost from a poorly insulated house?
walls 36%
floor 28%
roof 20%
windows 12%
doors 4%
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
Can heat loss through windows be reduced?
The insulating effect of the gap can be improved by removing the air and creating a vacuum.
A lot of heat energy can be lost through windows.
Double glazing adds an extra pane of glass. The air trapped between the two panes acts as an insulator and reduces
heat loss by conduction.
The problems with double glazing are that it can be expensive and that it is difficult to break in emergencies without a special hammer.
side-view
of double glazing
insulating layer
of air
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
How can heat loss through walls be reduced?
The air trapped in the cavity acts as an insulator and reduces any heat loss due to conduction through the bricks.
Most outside walls have an empty space between the two layers of bricks called a cavity.
Heat loss can also occur due to convection within the cavity. Plastic foam insulation can be pumped into the cavity to prevent this.
convection currents
in the cavity
foam insulation
prevents convection currents
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
How can heat loss through a roof be reduced?
The air warmed by radiators (and other heaters) is carried around a house by convection currents.
heat loss
loft insulation
Loft insulation contains trapped air and so forms an insulating layer between the loft and the rest of the house. This helps to reduce heat
loss through the roof.
The house becomes heated but,
if there is no roof insulation, the warm air continues to rise.
The heat eventually escapes through the roof and is lost due to conduction through the roof tiles.
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
How can heat loss from radiators be reduced?
Heat loss from a radiator can be reduced by placing shiny foil between the wall and the radiator.
A radiator produces infrared radiation.
Some of this heat energy is absorbed by the wall that the radiator is attached to, and so the wall heats up.
This can be a real problem on outside walls, where the heat energy absorbed by the wall can escape from the house.
The foil prevents heat radiation from reaching the wall by reflecting it back into the room.
This method of insulation is very cheap to install.
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
How can heat loss through doors be reduced?
Draught excluders are hairy or spongy strips that can be used to close the gaps around doors and windows.
A draught is the movement of air due to a convection current.
A lot of heat energy can be lost from a house due to draughts escaping through gaps under doors and around windows.
This is one of the easiest types of heat loss to prevent.
They prevent draughts escaping and so reduce heat loss.
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
How can curtains reduce heat loss?
A draught is the movement of air due to a convection current.
Warm air rises and is carried up towards the windows in a house by convection currents.
Fitting curtains and closing them can prevent draughts leaving a house and so reduce heat loss.
This heat energy can escape through gaps around windows that are uncovered.
In addition, curtains are opaque and so radiated heat does not pass through them.
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
17-11-2021
Air - a good insulator
Air trapped in feathers, cavity wall insulation, loft insulation, duvets and lagging greatly reduces heat loss by conduction.
Air is an insulator. This means that it is a poor conductor and heat will not readily move through it by conduction.
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
Exam Question
17-11-2021
X7(days) = 21000000
b)Loft Insulation
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
17-11-2021
device or part of a house | processes reduced |
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Write down six different ways in which heat flow from a house can be reduced in the table below:
draught excluders
convection
double glazing
conduction & convection
reflecting strips behind radiators
radiation
loft insulation
conduction & convection
carpets
conduction
cavity wall insulation
conduction & convection
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
Choose appropriate words to fill in the gaps below:
Thermal radiation, also known as __________ radiation, is how heat travels by _____________ waves.
Radiation travels equally in all ________and most quickly through a __________ where its speed is ___________ km/s.
All objects above absolute zero ( ________ oC ) give off thermal radiation.
Hot, _______ and rough surfaces emit radiation best.
Bright and ___________surfaces reflect radiation best.
heat
dark
directions
electromagnetic
300 000
- 273
vacuum
WORD SELECTION:
smooth
heat
dark
directions
electromagnetic
300 000
- 273
vacuum
smooth
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
PLENARY
3 keywords or basic facts
2 things you understand
1 question you still have
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
17-11-2021
Which ACP/VAA did you use today and how did you use it?
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
17-11-2021
#BeAmazingAtWIS
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
17-11-2021
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
17-11-2021
Type question here
PLENARY
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
BRONZE
SILVER
GOLD
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
17-11-2021
SPICE-OMETER
MILD
MEDIUM
HOT
FIERY
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
17-11-2021
Plenary – Which are true which are false?
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
BRONZE
SILVER
GOLD
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
Plenary – Which are true which are false?
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation
Keywords: Radiation, EM waves, Surface Area, Emit, Absorption, Double Insulation, Efficiency
Describe how thermal energy transfer may take place by radiation
Explain how emission and absorption of radiation are related to surface and temperature
Explain ways of reducing unwanted energy transfer, such as insulation