Energy Around Us Chapter 16

16.1 What is Energy? Energy is the. We use energy to. Without energy,. The SI unit for energy is ( ). ability to do work live and function living systems will die and non-living systems will not function Joules J

16.2 Forms of Energy Energy exists in many forms. Energy in ActionStored Energy Kinetic Energy Heat Energy Light Energy Sound Energy Electrical Energy Potential Energy Gravitational Potential Energy Elastic Potential Energy Chemical Energy Nuclear Energy

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

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.

Light Energy Light is the energy that enables us to SEE. Eg. Light energy is given out by a fire.

Electrical Energy Electrical energy is a form of energy that involves the flow of electric charges.

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.

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.

Chemical Energy Chemical energy is the energy stored in fuel (eg. Petrol, Batteries, Food) that can be released through chemical reaction.

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

16.3 Conversion of Energy Energy can be converted from one form to another.

Examples of Conversion of Energy Oven Toaster Electrical Energy  Heat Energy

Examples of Conversion of Energy Television Electrical Energy  Light Energy and Sound Energy

Examples of Conversion of Energy Burning Matchstick Chemical Energy  Heat Energy and Light Energy

Examples of Conversion of Energy Falling Apple Gravitational  Kinetic Potential Energy Energy

Examples of Conversion of Energy Atomic Bomb Nuclear Energy  Heat Energy, Light Energy and Sound Energy

Examples of Conversion of Energy A person shooting a rubber band Elastic Potential  Kinetic EnergyEnergy

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.

Example: Piling 1.The pile hammer is raised to a height. It gains gravitational potential energy. 2.During the fall, the gravitational potential 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.

Example: Swinging of Pendulum Pendulum bob has its maximum gravitational potential energy and zero kinetic energy at the starting position Pendulum bob loses all its kinetic energy and gain maximum gravitational potential energy as it comes to rest at its maximum height. Pendulum bob loses gravitational potential energy and gains kinetic energy as it swings down Pendulum bob loses all its gravitational potential energy and gain its maximum kinetic energy at the lowest position Pendulum bob starts to lose its kinetic energy and gain gravitational potential energy as it swings up

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.

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. Energy Conversion in Power plant Chemical Energy Heat Energy Kinetic Energy Eletrical Energy

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. Different types of Power Station

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.

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.

Plants and waste from animals Fuels such as biogas and alcohol are derived from biomass (plant materials or wastes from living things)

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.

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.

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.