Chapter 16 - Energy around Us
- 3. 16.1 What is Energy? Energy is the ability to do work . We use energy to live and function . Without energy, living systems will die and non-living systems will not function . The SI unit for energy is Joules ( J ).
- 4. 16.2 Forms of Energy Energy exists in many forms. Energy in Action Stored Energy Kinetic Energy Potential Energy Heat Energy Gravitational Potential Energy Light Energy Elastic Potential Energy Sound Energy Chemical Energy Electrical Energy Nuclear Energy
- 5. Kinetic Energy Kinetic energy is the energy that a body has due to its motion. Any object that moves has kinetic energy. Eg. A moving car has kinetic energy
- 6. Heat Energy Heat energy is the energy that flows from a region of higher temperature to a region of lower temperature. Eg. A hot cup of tea contains heat energy.
- 7. Light Energy Light is the energy that enables us to SEE. Eg. Light energy is given out by a fire.
- 8. Electrical Energy Electrical energy is a form of energy that involves the flow of electric charges.
- 9. Gravitational Potential Energy Gravitational Potential Energy is the energy an object has because of its position or location. Any object that is raised from a lower position to higher position gains gravitational potential energy.
- 10. Elastic Potential Energy Elastic Potential Energy is the energy an object has when it is stretched or compressed. Eg. A stretched rubber band or a compressed spring has elastic potential energy.
- 11. Chemical Energy Chemical energy is the energy stored in fuel (eg. Petrol, Batteries, Food) that can be released through chemical reaction.
- 12. Nuclear Energy Nuclear energy is a form of energy stored in the nuclei of atoms. Eg. Atomic bombs, nuclear reactor in a nuclear power plant
- 13. 16.3 Conversion of Energy Energy can be converted from one form to another.
- 14. Examples of Conversion of Energy Oven Toaster Electrical Energy Heat Energy
- 15. Examples of Conversion of Energy Television Electrical Energy Light Energy and Sound Energy
- 16. Examples of Conversion of Energy Burning Matchstick Chemical Energy Heat Energy and Light Energy
- 17. Examples of Conversion of Energy Falling Apple Gravitational Kinetic Potential Energy Energy
- 18. Examples of Conversion of Energy Atomic Bomb Nuclear Energy Heat Energy, Light Energy and Sound Energy
- 19. Examples of Conversion of Energy A person shooting a rubber band Elastic Potential Kinetic Energy Energy
- 20. 16.4 Principle of Conservation of Energy Principle of Conservation of energy states that: Energy cannot be created or destroyed. It is transferred from one body to another or transformed from one form to another. Total energy remains constant.
- 21. Example: Piling 1. The pile hammer is raised to a height. It gains gravitational potential energy. 2. During the fall, the gravitational potential energy energy is changed to kinetic energy. 3. As the hammer hits the pile, majority of the kinetic energy is transferred to the pile driving the pile into the ground. While some is converted to sound & heat energy.
- 22. Example: Swinging of Pendulum Pendulum bob loses all its kinetic energy Pendulum bob has its and gain maximum maximum gravitational gravitational potential potential energy and energy as it comes to zero kinetic energy at rest at its maximum Pendulum bob loses the starting position height. gravitational potential Pendulum bob starts to energy and bob loses all its Pendulum gains lose its kinetic energy kinetic energypotential energy gravitational as it and gain gravitational swings down maximum and gain its potential energy as it kinetic energy at the lowest position swings up
- 23. Power Station A power station uses fossil fuels such as coal, natural gas and oil. When these fossil fuels are burnt, the chemical energy stored in these fuels is released to boil water to form steam. The moving steam turns the generator. When the generator turns, electrical energy is produced.
- 24. Power Station A power station uses fossil fuels such as coal, natural gas and oil. When these fossil fuels are burnt, the chemical energy stored in these fuels is released Energy Conversion to boil water to form steam. in Power plant The moving steam turns the Chemical Energy generator. Heat Energy When the generator turns, electrical energy is produced. Kinetic Energy Eletrical Energy
- 25. Different types of Power Station A geothermal power plant uses heat from the earth. A hydroelectric power station uses energy from falling water. A wind turbine uses energy from wind to turn the turbines.
- 26. Conserving Energy With rapid growth in populations, urbanisation, industrialisation and globalisation, the world is consuming more energy. There is a need to conserve energy and use it wisely.
- 27. Free but expensive sources of energy Energy from the Sun, wind, rain, tides, nuclear fuels and heat from inside the Earth can be harnessed to do work and improve our quality of life. These alternative sources of energy are clean and do not run out. However, they are expensive or unsuitable to harness in some places.
- 28. Plants and waste from animals Fuels such as biogas and alcohol are derived from biomass (plant materials or wastes from living things)
- 29. Risky Sources The production of electrical energy using nuclear fuels is cleaner than that using coal or oil. However, there is a fear of exposure to harmful radiation should an accident happen in a nuclear power plant.
- 30. In Singapore…. Singapore is a small country without natural resources. Although it is one of the major oil refinery centres of the world, it has to import oil and gas from other countries for production of electrical energy. There is a need to conserve energy, especially for Singapore.
- 31. Caring for Mother Nature Humans’ need for more and more energy has sparked the global concern that non- renewable energy sources such as fossil fuels will run out one day. The use of such fuels has heightened environmental concerns regarding air and water pollution as well as global warming.