Contains the full lesson along with a supporting toolkit, including teachers’ notes.
What is energy?
We use the word energy in many different ways and are not too troubled about defining it. However, in physics, it has a specific and precise definition. To a scientist energy is the ability to do work. ‘Work’ is defined as being done when a force acts on an object, accelerating it over a distance.
Power is then defined as the rate of doing work. For example, a car that travels a kilometre more quickly than another is more powerful i.e. it has used the same energy in a shorter interval of time.
There are many forms of energy including potential, kinetic, elastic, electric, magnetic, chemical, thermal and nuclear. The law of conservation of energy tells us that energy can neither be created nor destroyed, but it can be transformed from one type to another. The challenge is to develop ways of transforming energy that already exists into forms that are more useful.
In this lesson we discuss some of the technologies used by the ESB to transform energy into the valuable product called electricity.
Generating electricity - the fundamentals
An electrical generator is usually a rotating device that continuously moves an assembly of conductors through the magnetic field. Obeying Faraday’s law of electromagnetic induction, this movement creates the electromotive force (EMF) necessary to drive an electric current. The generator is rotated by some form of engine, often a turbine. Of course, this turbine must be driven by some other source of energy. It is these sources of energy that form the topic of much debate and concern.
Burning fossil fuels
Fossil fuels, such coal, oil or natural gas, are hydrocarbons and are easily burned. These fuels are commonly used as sources of heat in thermal power stations in which heat energy is converted into electricity. The heat either converts water into steam or ignites fuel (similar to a combustion engine) which then drives a turbine (mechanical energy).
When fossil fuels are burned they produce carbon dioxide (CO2) and nitrous oxide (N2O), These are greenhouse gases that contribute to the modern problem of global warming. In addition, fossil fuels take tens of millions of years to form naturally and are now classified be non-renewable. Accordingly, the focus is now on renewable energy sources i.e. sources that are replenished naturally over a reasonable period of time. These include water, wind, the sea, the sun, heat from the earth itself and organic matter (biomass).
Science and Technology in Action (STA) is designed to support the teaching and learning of science and related subjects.
Each annual edition of STA contains a set of lessons that are industry led to be used by all teachers in second level schools. These lessons are available on this website and can be downloaded in a pdf format along with their supporting materials.
A hard copy is usually sent out for free to all second level schools each school year.
Science and Technology in Action (STA) is proudly supported and partnered by some of Ireland’s leading organisations and is produced in close cooperation with the support services of the Department of Education and Skills and the Irish Science Teachers Association (ISTA).
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