P2 Energy Flashcards
How do you measure energy
Joules (J)
kilojoules (KJ)
What do you need energy for
Keep body warm To breathe Move Talk Growth (muscles, bones, brain)
What happened if you take in too much energy
Your body stores it as fat to use in the future
What is energy stored in
Food and fuels
what do you need to burn both food and fuels
Oxygen
What is the law of conservation of energy
Energy cannot be created or destroyed only transfered
What are types of energy store
Chemical (food) Thermal Kinetic (moving) Gravitational potential Elastic Light Sound
How do you transfer energy on a daily basis
When using your phone
After use there is less energy in the chemical store and more in the thermal store of the surroundings
What do we mean when we say saving energy
Energy is conserved but if we transfer more of it to the useful store we save the fuel
What does dissipated mean
Energy that has become spread out or ‘wasted’ by heating the environment
Why do things happen
Energy tell us what changes are possible - forces not energy explain why things move.
The force provided by the energy makes something move or do something
What is temperature
A measure of how hot or cold something is
What do you use to measure temperature
A thermometer in degrees Celsius
What is the difference between energy and temperature
You can have a swimming pool and a beaker the same temp but the swimming pool has more thermal energy in store because of the volume
What happens if you heat a solid
The particles vibrate more
What happened if you heat a liquid or gas
The particles move faster and vibrate more
How do things get hotter
When you heat solids liquid or gases the particles move or vibrate faster
How can you increase the temperature of something
Using energy
How much energy do you need to heat something
It depends on:
The mass of material
What the material is made of
The temp you want to ride to
What is equilibrium
When no more energy is transferred between thermal stores - they stay the same temp
What is conduction
It holds energy well and transfers it very quickly
What can energy be transferred by
Conduction
Convection
Radiation
How does conduction work
The particles transfer energy by colliding with each other when they vibrate
What are insulators
A material that does not conduct electricity or transfer energy well
What is convection
The transfer of energy by the movement of gases or liquids
What is radiation
The transfer of energy as a wave
What is convection current
The movement of liquid or gases (heating soup)
How does sound energy travel
Energy is transferred to the surroundings - the air gets a bit warmer and the particles in the air move faster and the particles in the walls vibrate more
When is energy transferred by conduction
I’d there’s a temperature difference between the ends of it
How fast does energy transfer
It transfers much slower through a insulator like wood
What is infrared radiation
Radiation given off by the sun and other objects that brings about energy transfer
Do you need particles to transfer energy by radiation
No
What does radiation emitted depend on
The temperature
The surface
What is a thermal imaging camera
A camera that absorbs infatuated and produces a (false colour) image
What are fossil fuels
Energy resources that were formed millions of years ago
What does non-renewable mean
That you cannot easily get more of the material when they run out
What are example of non-renewable sources
Oil
Coal
Gas
What are examples of renewable sources
Wind Water (any type)
What is the main problem of burning fossil fuels
They let off carbon dioxide which is a greenhouse gas and contributes to climate change
How do thermal power stations work
A fuel burns to heat water and produce steam
The steam powers a turbine
The turbine powers a generator
This provides a push so current flows
