Physics energy-2

OBESITY AMONG STUDENT

WHAT IS ENERGY???

• Energy can be define as the ability to do work

• Example:

# Work is done when Lily picks up a book on the floor and places it on a table.

FORMS OF ENERGY

NUCLEARENERGY

SOUNDENERGY

ELECTRICALENERGY

CHEMICALENERGY

LIGHTENERGY

HEAT ENERGY

KINETICENERGY

POTENTIAL ENERGY

MECHANICALENERGY

ENERGY

• HEAT ENERGY# Heat energy is set free when a material burns.# Heat energy flows from a place or material of high

temperature to lower temperature.# Uses of heat energy: a) To dry wet clothes b) To boil water and cook food

• LIGHT ENERGY# Any object that give out light possesses light energy.# We will not able to see things if no light energy

reaches our eyes.# Uses of light energy: a) It supplies energy to solar cells b) It is used by green plants in photosynthesis

• CHEMICAL ENERGY# Chemical energy is present in chemical substances and

usually release in a chemical reaction.# It may appear in different forms such as: a) electricity from a battery# Uses of chemical energy: a) Food – to supply energy to living things b) Fuels – to supply energy for cooking, machines and

vehicles to work

• ELECTRICAL ENERGY# Electrical energy is the energy produced by an electric

current or electric charges#Sources of electrical energy a)lightning b)batteries# Uses of electrical energy a) to light lamps such as fluorescent lamps b) to turn electric motors in fans and engines

• SOUND ENERGY# Sound energy is produced by vibrations and travels

outwards in waves and can be detected with our ears.# Sources of sound energy a)thunder b)musical instruments# Uses of sound energy a)singing of entertainment b)talking for communication with people

• KINETIC ENERGY# Kinetic energy is any object which is moving possesses# Sources of kinetic energy a)wind b)waves# Uses of kinetic energy a) wind- used for sailing ship b) river- used to turn turbines and dynamos for generating

electricity

• POTENTIAL ENERGY# Potential energy is stored energy and the energy of

position.# Potential energy is present in objects which are: a) compressed b)stretced c)raised from its position# Uses of potential energy: a)to operate an alarm clock b)to move a baby’s cradle up and down

• MECHANICAL ENERGY# Mechanical energy is the total of potential and kinetic

energy possessed by an object because its position changing.

# Examples of objects which have mechanical energy include:

a)a swinging pendulum b)a see-saw in use

• NUCLEAR ENERGY# Nuclear energy is the energy stored in the nucleus of

an atom# Its released in two ways: a)nuclear fission (‘’fission’’ means breaking up) b)nuclear fusion (‘’fusion’’ means combining)# Its released in the form of: a)heat energy c)sound energy b)light energy d)harmful radiation# Uses of nuclear energy: a)it is used to power submarines b)it is used to keep satellites in orbit

THE SUN AS THE PRIMARY SOURCE OF ENERGY

#The sun generates a large amount of energy by nuclear fusion.

ENERGY OF THE SUN

ENERGY IN WIND,WAVES AND RAIN

ENERGY IN FOSSIL FUELS(natural gas,petroleum,coal)

ENERGY IN PLANTS,ANIMALS AND HUMAN BEINGS

ENERGY FOR OPERATING APPLIANCES (e.g. SOLAR CALCULATORS,SOLAR COOKERS)

SOURCE OF ENERGY

#There are several sources of energy:SOURCE OF ENERGY

SOLAR(SUN)

WIND

WAVES AND TIDES

HYDRO(FLOWING WATER)

GEOTHERMAL

BIOMASS

FOSSIL FUELS

• SOLAR ENERGY# Solar energy is energy from the sun.# Uses of solar energy: a)heating water b)producing electrical energy

• WIND# Winds are caused by the uneven heating of

the Earth’s surface.# Winds possess kinetic energy# Uses of winds: a)moving sailing ships b)turning windmills to grind corn

• WAVES AND TIDES# Waves are caused by the wind blowing over

the surface of the ocean.# Its moving in and out from the seashore

have potential energy and kinetic energy.# Tides are caused by the gravitational pull of

the moon and sun,and the rotation of the earth.

# Its flowing in and out from the shore twice a day. These moving tides possess kinetic energy while the high tides contain potential energy.

• HYDRO # Water from a river can be blocked to form a dam.# Water stored in a dam has potential energy and it

has kinetic energy when it flows out of it.

• GEOTHERMAL # “Geo” means “earth” and “thermal” means “heat”.

Geothermal energy is heat energy obtained from deep in the earth.

# Sometimes water from a lake is channeled inside the earth to be heated by hot rocks and then pumped out again as steam.

# Uses of steam: a) heat houses and factories. b) drive turbines and dynamos to produce electrical

energy.

• BIOMASS# Biomass energy is the energy obtained from

plants and animal materials by: a) burning them b) decomposing them using bacteria

• FOSSIL FUELS # Fossil fuels were formed from plants and

animals which became buried in the earth long ago.

# It consist of coal,natural gas and petroleum.# Coal is used in temperate countries for warming

houses.# Natural gas is used as a cooking fuel.# Petroleum contains many types of fuel such as

aviation fuel,petrol.kerosene and diesel.

RENEWABLE AND NON- RENEWABLE ENERGY SOURCE# Renewable sources are energy sources which cannot be used up;they are always available# Non- renewable sources are energy sources which will be used up one day

ENERGY SOURCES

RENEWABLE

#SOLAR#HYDRO#WIND

#WAVES#TIDES

#BIOMASS

NON-RENEWABLE

# FOSSIL FUELS*COAL

*NATURAL GAS*PETROLEUM

# GEOTHERMAL#NUCLEAR

CONSERVING ENERGY SOURCESTHE USE AND MANAGEMENT OF

ENERGY SOURCES

# Energy sources have supplied us energy which has made our lives more comfortable

# To avoid wastage and creating enviromental problems as such :

a) Save energy b) Improve efficiency c) Reduce enviromental pollution d) Mantain the balance of nature e) Carry out enviromental studies f) Use alternative energy sources