1. WHAT is Energy?
1.1. Energy efficiency simply means using less energy to perform the same task – that is, eliminating energy waste. Energy efficiency brings a variety of benefits: reducing greenhouse gas emissions, reducing demand for energy imports, and lowering our costs on a household and economy-wide level.
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. Potential Energy- refers to stored energy due to conditon, a body's position or condition
3.1.1. Chemical Potential Energy
3.1.2. Gravitational Potential Energy
3.1.3. Elastic Potential Energy
3.2. Kinetic Energy
3.2.1. Energy that an object possesses due to its motion.
3.2.1.1. e.g. All moving objects have kinetic energy.
3.3. Heat
3.3.1. Energy that flows from a region of higher temperature to a region of lower temperature.
3.3.1.1. e.g. HOMES- cooking, heating water & ironing clothes. FACTORIES- melting metals, creating steam to turn turbines & making chemicals react.
3.3.1.2. Transferred by conduction, convection & radiation.
3.4. Light
3.4.1. Energy that enables us to see.
3.4.1.1. Sun is the main source of light energy- plants for photosynthesis.
3.4.1.2. Lumionous objects give out light energy.
3.5. Sound
3.5.1. Energy produced when objects vibrate.
3.5.1.1. USED FOR: communication, entertainment & warnings.
3.6. Electricity
3.6.1. Energy that results from the flow of charged particles.
3.6.1.1. This energy can be transformed into many other forms of energy.
3.6.1.2. 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. Power stations generate this electricity needed in homes, schools & offices. The series of following energy changes take place:
4.2.1.2. Nuclear power stations bombard radioactive elements with neutrons. This causes large amounts of heat to boil water into steam to turn turbines.