Chapter 2 🖕🏼 Flashcards
How does loft insulation work?
Reduces energy lost through roof by conduction
Fibreglass is a good insulator
How does cavity wall insulation work?
Reduces energy lost through outer wall of house
Insulation fills cavity so heat can’t escape easily
How does putting aluminium foil between a radiator and the wall help?
Foil reflects heat away from wall
How do double glazed windows help?
Reduces energy lost through conduction
Two panes of glass with vacuum between
Ways to insulate house
Loft insulation Cavity wall insulation Double glazed Windows Aluminium behind radiators Thicker bricks on external walls
When a substance is heated, what does the temperature rise depend on?
Amount of energy supplies to it
Mass of substance
What the substance is
What is the specific heat capacity of a substance?
The energy needed to raise temperature of 1kg of the substance by 1 degree
What is the equation for energy transferred (J) using mass, SHC and temperature change
Energy transferred = mass x SHC x temperature change
When does the temperature of an object increase?
When it absorbs more radiation than it emits
What does the temperature of the earth depend on?
Absorption and emission of infrared radiation
What do all objects emit?
Infrared radiation
The higher the temperature of an object…
The more infrared radiation it emits
What is a perfect black body?
An object that absorbs all radiation that hits it
How does cavity wall insulation work?
Reduces energy lost through outer wall of house
Insulation fills cavity so heat can’t escape easily
How does putting aluminium foil between a radiator and the wall help?
Foil reflects heat away from wall
How do double glazed windows help?
Reduces energy lost through conduction
Two panes of glass with vacuum between
Ways to insulate house
Loft insulation Cavity wall insulation Double glazed Windows Aluminium behind radiators Thicker bricks on external walls
When a substance is heated, what does the temperature rise depend on?
Amount of energy supplies to it
Mass of substance
What the substance is
What is the specific heat capacity of a substance?
The energy needed to raise temperature of 1kg of the substance by 1 degree
What is the equation for energy transferred (J) using mass, SHC and temperature change
Energy transferred = mass x SHC x temperature change
When does the temperature of an object increase?
When it absorbs more radiation than it emits
What does the temperature of the earth depend on?
Absorption and emission of infrared radiation
What do all objects emit?
Infrared radiation
The higher the temperature of an object…
The more infrared radiation it emits
What is a perfect black body?
An object that absorbs all radiation that hits it
How does loft insulation work?
Reduces energy lost through roof by conduction
Fibreglass is a good insulator
How does cavity wall insulation work?
Reduces energy lost through outer wall of house
Insulation fills cavity so heat can’t escape easily
How does putting aluminium foil between a radiator and the wall help?
Foil reflects heat away from wall
How do double glazed windows help?
Reduces energy lost through conduction
Two panes of glass with vacuum between
Ways to insulate house
Loft insulation Cavity wall insulation Double glazed Windows Aluminium behind radiators Thicker bricks on external walls
When a substance is heated, what does the temperature rise depend on?
Amount of energy supplies to it
Mass of substance
What the substance is
What is the specific heat capacity of a substance?
The energy needed to raise temperature of 1kg of the substance by 1 degree
What is the equation for energy transferred (J) using mass, SHC and temperature change
Energy transferred = mass x SHC x temperature change
When does the temperature of an object increase?
When it absorbs more radiation than it emits
What does the temperature of the earth depend on?
Absorption and emission of infrared radiation
What do all objects emit?
Infrared radiation
The higher the temperature of an object…
The more infrared radiation it emits
What is a perfect black body?
An object that absorbs all radiation that hits it
What is a conductor?
Something that lets energy travel through it
A good insulator must have…
Low thermal conductivity
What is conduction?
Where vibrating particles transfer energy to neighbouring particles
What is the thermal conductivity of a material
How much energy it transfers per second by conduction
What does the energy transfer through a layer of material depend on 3
Temperature difference
Thickness
Thermal conductivity
Why does the colour of an object change as it is heated?
It emits more radiation at shorter wavelengths
What type of radiation does earth emit?
Long wave
How to reduce energy transfer? 2
The thermal conductivity of the material should be as low as possible
The thickness of the insulating layer should be as big as possible
What will an object with a constant temperature do?
Emit radiation across a continuous range of wavelengths
What do greenhouse gases do?
It absorbs long wave length tradition from earth to stop it reflecting into space
How do solar panels work?
Absorb infrared radiation from the sun to generate electricity or heat water
How to reduce energy transfer? 2
The thermal conductivity of the material should be as low as possible
The thickness of the insulating layer should be as big as possible
What will an object with a constant temperature do?
Emit radiation across a continuous range of wavelengths
What do greenhouse gases do?
It absorbs long wave length tradition from earth to stop it reflecting into space
How do solar panels work?
Absorb infrared radiation from the sun to generate electricity or heat water
