1. WHAT is Energy?
1.1. Energy is the ABILITY TO DO WORK
1.2. Energy can be used either for living or functioning
1.3. S.I. unit for energy: Joule (J)
2. Sources of Energy
2.1. Renewable Sources
2.1.1. Replenishable in a short period of time due to unlimited supplies or new growth.
2.1.1.1. Solar Energy
2.1.1.1.1. Energy directed from the sun
2.1.1.1.2. Enables plants to make food & animals to live.
2.1.1.1.3. Can be converted to heat & electrical energy.
2.1.1.2. Wind Energy
2.1.1.2.1. Kinetic Energy of wind generates the wind turbines to produce electrical energy.
2.1.1.3. Wave Energy
2.1.1.3.1. Kinetic Energy of waves generate electricity in wave farms.
2.1.1.4. Biomass
2.1.1.4.1. Made from living or recently living plants & animals e.g. wood, animal waste, crops
2.1.1.4.2. Contains stored energy from the Sun after photosynthesis.
2.1.1.4.3. Obtainable through:
2.2. Non-Renewable Sources
2.2.1. Energy that is limited which is likely to run out one day.
2.2.1.1. Fossil Fuels
2.2.1.1.1. Contains Chemical Potential Energy. When burnt, CPE converts into other forms of energy such as light & heat energy.
2.2.1.1.2. Disadvantage-causes global warming & air pollution.
2.2.1.1.3. Coal, Natural Gas & Oil
3. Forms of Energy
3.1. Light
3.1.1. Energy that enables us to see.
3.1.1.1. Sun is the main source of light energy- plants for photosynthesis.
3.1.1.2. Lumionous objects give out light energy.
3.2. Sound
3.2.1. Energy produced when objects vibrate.
3.2.1.1. USED FOR: communication, entertainment & warnings.
3.3. Electricity
3.3.1. Energy that results from the flow of charged particles.
3.3.1.1. This energy can be transformed into many other forms of energy.
3.3.1.2. Electrical appliances require electricity to work.
4. Energy Transformations
4.1. Works with the concept that one form of energy can change into many other forms of energy.
4.1.1. e.g. PHOTOSYNTHESIS IN PLANTS: Light Energy (from the sun) -> Chemical Potential Energy (starch)
4.1.2. HAIR DRYER: Electrical Energy -> Heat Energy + Sound Energy
4.1.3. RELEASED BOW: Elastic Potential Energy (bow) -> Kinetic Energy (arrow)
4.2. GENERATION OF ELECTRICITY
4.2.1. Electrical generators are used to convert kinetic energy of steam turbines to electricity.
4.2.1.1. Nuclear power stations bombard radioactive elements with neutrons. This causes large amounts of heat to boil water into steam to turn turbines.