8K Energy Transfers Flashcards
The sun’s heat energy that travels across space to warm Earth is called……
……..infra-red (or IR)
Are dark or light colours the best good emitters and absorbers of radiation
Dark
Which of these is not a way of trying to reduce energy bills? A increasing the insulation in your home B using more efficient appliances C using appliances with high power ratings D using solar power to heat water
C using appliances with high power ratings
What does emit mean?
To give out.
What does thermal insulator mean?
A material that does not allow internal (thermal) energy to be transferred through it easily.
Which list of materials shows only insulating materials? A wool, feathers, copper B feathers, wood, carpets C iron, copper, steel D plastic, aluminium foil, wood
B feathers, wood, carpets
What does absorb mean?
‘To soak up’ or ‘to take in’.
What happens to the energy in a cup of iced tea left in a cold kitchen?
It will increase as the iced tea gains energy from the air in the kitchen until they are both at the same temperature.
Temperature is measured in,,,,,,
One of
degrees Celsius (°C).
Fahrenheit (F)
Kelvin (K)
What is a fossil fuel?
A fuel formed from the dead remains of organisms over millions of years (e.g. coal, oil or natural gas).
What units for energy are used on
electricity bills?
kilowatt-hours
What does evaporate mean?
When a liquid turns into a gas.
The efficiency of an appliance is calculated
by…….
…….comparing the useful energy
transferred to the total energy supplied
What happens to the energy in a hot cup of tea left in a cold kitchen?
It leaves the tea until it is a the same temperature as the air in the room
How does sweating work?
Sweating cools us down when the sweat evaporates and takes some heat energy with it.
What happens to the particles in evaporation?
When some of a liquid evaporates, it is the particles moving the fastest that escape and form a gas.
What are the units for measuring power?
Watts (W) or kilowatts (kW)
Which word describes the way energy is transferred through solids by heating?
Conduction
Which type of surface would reflect
infrared radiation the best?
A white and dull B black and shiny
C white and shiny D grey and dull
C white and shiny
What does efficiency mean?
How much energy something wastes.
Why does the cold air near an ice lolly move downwards?
It is colder and denser than the air further away from it.
The amount of thermal energy in an object depends on what three things?
Its mass, its temperature, the material it is made from.
How do you calculate payback time?
Payback
time = cost of change/savings per year
What is the unit for measuring energy.
a Joule (J)
What does thermal conductor mean?
A material that allows internal (thermal) energy to be transferred through it easily.
How can you find the power of an
appliance?
Look for the power rating on the label
Why do many insulating materials contain
trapped air?
1) gases are poor conductors and
2) gases cannot transfer energy by convection if they cannot move.
Why are solids are better heat conductors than liquids or gases?
The particles are closer together in solids.
What is climate change?
Changes that will happen to the weather as a result of global warming/ the rlease of greenhouse gases (e.g carbon dioxide and methane).
When one end of a piece of metal is heated the particles vibrate ….
……… more and the vibrations are passed from particle to particle.
What does reflect mean?
To bounce off a surface
What does ‘payback time’ mean?
The time it takes to save enough money
on energy bills to pay for a change
The rate at which energy is transferred is called
Power
Which word describes the way energy is transferred by heating in fluids?
Convection
