KS3 Energy

The ULTIMATE energy source The sun is the ultimate source of all our energy. For example, we often get energy from beef: BEEF comes from COWS, COWS eat GRASS, GRASS gets energy from the sun by PHOTOSYNTHESIS

The 9 types of energy Type 3 example sources Heat Kinetic (movement) Nuclear Sound Light Chemical Electrical Gravitational potential Elastic potential

Electricity Light + heat Energy changes To describe an energy change for a light bulb we need to do 3 steps: 1) Write down the starting energy: 3) Write down what energy types are given out: 2) Draw an arrow Electricity Light + heat What are the energy changes for the following…? An electric fire A rock about to drop An arrow about to be fired

Conservation of Energy In any energy change there is ALWAYS some “waste” energy: e.g. a light bulb: Electricity Light + heat In this example HEAT is wasted – it’s given to the surroundings. Waste energy is virtually always heat and it’s always given to the surroundings.

Heat transfer 1) Conduction – this is when heat is passed on through a solid by vibrations of particles: 2) Convection – this is when “heated stuff” moves somewhere else and takes heat with it: 3) Radiation – this is when heat is moved by “heat waves” (infra-red) – this is how heat reaches us from the sun:

Power stations Generator Turbine Cooling tower Transformer Boiler

What does each part do? The boiler is where the fuel is burnt to boil water The steam from the boiler is used to turn a turbine The turbine is connected to the generator, which acts like a dynamo – it generates electricity out of movement The steam is cooled down and turned back into water in the cooling tower

Renewable vs. non-renewable fuels A ________ energy source is blatantly one that can be _______ (“renew = make again”), e.g. _____, solar power etc. Biomass is also an example of a renewable energy source – ______ is a form of biomass. A ___________ energy source is one that when it has been used it is gone forever. The main examples are ____, oil and gas (which are called ______ ____, as they are made from fossils), and nuclear fuel. Words to use – non-renewable, coal, wind, renewable, fossil fuels, wood, renewed

Non-renewable energy sources Advantages Disadvantages Pollution – CO2 leads to global warming and SO2 leads to acid rain Cheap fuel costs Coal, oil, gas and nuclear Good for “basic demand” Fuel will run out Costs a lot of money to decommission a nuclear plant Short start-up time

Other ways of generating electricity… Can we drive the turbine without burning anything?

Other ways of generating electricity… Wind Hydro-electric Wave Tidal

Renewable energy sources Advantages Disadvantages Often depend on the weather – is it sunny??? Clean Coal, oil, gas and nuclear Won’t run out Very expensive Energy is “dilute” – in other words, it’s very spread out Easily accessible