CHAPTER 6: Sources of Energy

6.1 Understanding various forms and sources of energy

Forms of energy1. energy is defined as the ability to do work and is measured in joules (J).2. All living things need energy to conduct their daily activities.3. energy can found in many forms such as HEAT ENERGY, POTENTIAL ENERGY, NUCLEAR ENERGY,SOUND ENERGY, ELECTRICAL ENERGY, KINETIC ENERGY, LIGHT ENERGY AND CHEMICAL ENERGY.

KINETIC ENERGY.

• Kinetic energy is energy possessed by a moving object.

• The kinetic energy of an object increases when it moves faster.

• Examples:• A flying bird• A moving car

POTENTIAL ENERGY

Potential energy is the energy stored in an object.a. position - gravitational force energy, example: Coconut on treeb. condition - elastic potential energy, examples: stretched spring, stretched rubber band.

HEAT ENERGY

• Stored in hot object. Examples Sun, fire, and boiling water.

• The hotter the object, the higher the heat energy it gives out.

• The Sun is the main sources of heat energy.

LIGHT ENERGY • Energy produced by an object that

emits light. • Examples Lamp, fire, lightning, bulb,

and candle.• Can detect by eye.

CHEMICAL ENERGY• Stored in chemical substances such as

fuel, food and electrochemical cell

SOUND ENERGY• Produced by a vibrating object.• Sound can transferred by gases, liquid

and solid. • Sound cannot travel in a vacuum.

ELECTRICAL ENERGY• Produced by the electric charges that

flow. Sources of electrical energy are dynamos, batteries, solar panel/cell and generator.

NUCLEAR ENERGY• known as atomic energy.• Obtained from elements such as

plutonium and uranium

Sources of energy• There are various sources of energy on

Earth such as:• fossil fuel (petroleum, natural gas and

coal)• biomass fuels (from plant and animal)• Radioactive substances(Plutonium and

uranium are used in nuclear power station to produce nuclear energy)

• Wind (Caused by winds blowing on the surface of the sea)

• Water in mountain areas (Changes potential energy to kinetic energy to generate electrical energy)

• Waves• Geothermal (heat from inside the Earth)• The Sun.

Energy change• Energy can changes from one form into

another.• We use a machine to change one form

of energy into another form that is needed to do certain work.

• A machine that can change energy from one form into another is called an energy converter.

Examples:• Moving car (chemical energy into kinetic energy)• A radio (electrical energy into sound energy)• Electric kettle (electric energy into heat energy)• Alarm clock (potential energy into kinetic energy

into sound energy)• A falling coconut (potential energy into kinetic

energy)

Renewable and non-renewable energy

• Renewable energy sources are energy sources that can be replaced when they have been used. This means that the supply of these energy sources will not be used up.

• Non renewable energy sources are energy sources that cannot be replaced and will finally be used up.

Renewable energy sources• Wind• Geothermal• Sun• Waves• Biomass• Water

Non Renewable energy sources• Fossil fuels• Radioactive metals

• They take so long to form and therefore cannot be replaced.