Flashcards in Energy Deck (26):
What is energy measured in?
Joules or kilojoules
What are the three fossil fuels?
Coal, oil and gas
What will happen if you use less energy then you take in?
The energy will get stored as body fat and you will gain weight
Butter stores a lot of energy per 100g
Celery stores a lot of energy per 100g
More energy is used to stand than is used to sit.
To lose weight, you should eat more fruit and vegetables
You don't use energy when you are sleeping.
What is heat?
Heat is a form of energy. It is the average kinetic energy of all the particles in a body
What is temperature?
Temperature is a measure of how hot or cold a body is but does not tell us how much heat energy a body contains. It is measured in degrees Celsius (°C) or kelvin(K)
What do fuels respire with?
Fuels + oxygen ->
Carbon dioxide +water + energy
What type of energy is fuel?
What type of energy is in food?
How does a power station work?
Heat energy from the fuel is transferred to the water in the boiler. The water boils rapidly and high pressure steam is generated. This then turns the turbine creating kinetic energy. This energy from the turbine then goes into a generator to make electrical energy.
What is non-renewable energy?
Once it is used it can't be used again-e.g coals, oils, gas, nuclear
What is renewable energy?
It can be used again e.g wind, solar, tidal, waves, hydroelectric, geothermal and biomass. If you can replace it within your lifetime, 75 years, it is renewable
What are the three types of thermal heat transfers?
Conduction, convection and radiation
What is conduction?
In conduction the particles transfer energy by colliding with each other when they vibrate. The energy transfers until the two sides are the same heat. If one side is being continuously heated one side will always be hotter than the other. Some materials are harder to transfer energy through than others. Gases and liquids don't conduct well as the particles are further apart.
What is convection?
Convection is when you heat up a gas or a liquid and it rises. This happens as the particles that are being heated, have more energy, spread out and rise this leaves the area where the warm particles where less dense. This means that the cold air falls into the gap.
What is radiation?
Infrared radiation travels as waves not by particles. This allows it to travels through a vacuum like space. The sun energy is transferred by radiation that is how it travels through space. Infrared radiation is also known as 'thermal radiation' or 'heat'
How do you calculate work?
Work = force x distance
What is power?
Power is the rate at which work is done
How do you calculate power?
(Work x distance)divided by time taken = power
What is the unit for power?
Watts (w) 1KW = 1000W