Energy_Concept_2
Types of energy
Types of energy
Several different types of energy can be identified at primary level. At a higher level of scientific understanding it is possible to identify just two forms, kinetic and potential; but this theory is best left to secondary level work.
Almost ail of our energy requirements can be traced back (either directly or indirectly to the Sun. By looking at these pathways, it is possible to identify many different forms of energy.
Of these, the key ones are:
Kinetic movement energy. This could be the energy of a running person, a ball or an engine. The movements of air (wind) and water (rivers, waves) are important sources of kinetic energy that can be transformed into other forms, or used directly to move things.
Light visible radiation. This is used by plants for photosynthesis. It also enables us to use the sense of vision.
Thermal heat energy. No energy transformation is a hundred per cent effective, and some energy is turned into low level thermal energy at every stage. The idea of thermal energy IS important for understanding chemical changes
Electrical — the flow of current is a particularly useful form of energy since it can be transmitted and changed into other forms of energy with relative ease. However, it is relatively difficult to store.
Nuclear nuclear fission (the breakdown of atoms) releases intense thermal energy that can be harnessed.
Potential — 'stored energy This has three familiar forms:
gravitational, chemical and elastic, Gravitational potential energy is stored by raising a mass against gravity; it can be released as kinetic energy when the mass is allowed to fall. Chemical potential energy can be released by chemical changes; examples include food (broken down to release energy in the body)r plant and fossil fuels such as wood, coal and oil (burned to release heat) and batteries (chemicals react to produce electricity). Elastic potential energy is the 'stretch' materials (such as springs, rubber bands and rubber balls) which will bounce back',
Most of the technology that we surround ourselves with is primarily concerned with turning one form of energy into another. Finding more successful, cheap or efficient (energy saving) ways of doing this -is the key area in which technologicaI advances are made For example cars have become more efficient in changing chemical into kinetic energy and thus use fuel than before.
Engine a device for turning stored energy into useful work or movement
In every second, an average of 4 gigajoules (4000,00Q000 joules) of energy from the Sun falls on each square kilometre of the Earth at the equator
see concept 1