energy. almost all energy we use comes originally from the sun

ENERGY

Almost all energy we use comes

originally from the sun.

We use energy sources to generate

electricity.

There are two types of energy -- stored

(potential) energy and working (kinetic)

energy. 

Radiation, conduction, convection

Conduction, convection and

radiation are the three major methods of heat

transfer.

They are the three different ways that heat can

spread.

Conduction is the transfer of heat

through an object.

When something is heated the atoms

start to move faster.

As they move faster they collide with

atoms next to them, which collide with

atoms next to them.

This creates a chain reaction that actually

moves the heat along a path, outward from the starting point where the

heat was added.

This is what's happening if you've ever set a pan on the

stove.

The handle gets warm even though only the bottom touches the burner because the metal conducts the

heat.

heat travels from candle to metal rod to hand

Convection is the transfer of heat

energy by movement of

currents.

It causes currents of warm and cool air to move and occurs in liquids and gases.

You may have heard of the

phrase “hot air rises”.

This is convection.

Heat leaves a coffee cup as the currents of steam

and air rise.

The heat moves with the fluid.

Radiation has to do with light.

One of the most important types of

radiation we receive on earth is from the

sun.

The sun sends waves of heat

through space to warm our planet.

Only about 51% of the sun’s rays are absorbed by the earth

The light that you see is actually

made up of waves.

When something is hot, like the burner on your stove, it releases some

of its energy in the form of waves.

The waves travel through the air until they hit something, which gets heated

up.

This is why you can feel the heat from your stove even if

your hand isn't actually touching it.

The burner literally

'radiates' heat.

The different forms of energy

are stored in different ways.

Electrical energy cannot

be stored directly.

Electrical energy can be indirectly stored by

converting the electrical energy to some other

form of energy ("storage" energy).

When a supply of electrical energy is

required, the storage energy is reconverted

back to electrical energy.

Large quantities of "storage" energy are difficult to store and

reconvert.

Energy sources are divided into two groups –renewable (energy we can use over and over again) and nonrenewable (energy that

we are using up and cannot recreate in a short period of

time).

  Renewable energy sources include solar

wind, geothermal, biomass, and hydropower. 

Another nonrenewable energy source is the element uranium, whose atoms we

split (through a process called nuclear fission) to create nuclear energy.

Non-renewable Energy

Much of our current energy supply comes from coal, oil, natural

gas, or radioactive elements.

They are considered non-renewable because once they are removed from

the ground and used, they are not immediately

replaced.

In fact, the world's natural gas, crude

oil and coal deposits took millions of years to form

Petroleum Products• Ink

• Crayons

• Bubble gum

• Dishwashing liquids

• Deodorant

• Eyeglasses

• CDs and DVDs

• Tires

• Ammonia

• Heart valves

RENEWABLERENEWABLEENERGYENERGY

Renewable energy refers to sources of

energy that are always there.

You might think that we would be tapping

these energy resources, but there is a catch.

While the energy is there, the cost of getting it is

actually greater than using our more popular energy sources of fossil fuels and

uranium.

An important advantage of

renewable energy is that it produces much

less pollution.

Renewableenergy

Renewable sources of energy can be used over and over again

Renewable resources include solar energy,

wind, geothermal energy, biomass and

hydropower.

Solar energy comes from the

sun.

Some people use solar panels on their

homes to convert sunlight into electricity.

Wind turbines, which look like giant

windmills, generate electricity.

Geothermal energy comes

from the Earth's crust.

Engineers extract steam or very hot water from

the Earth's crust and use the steam to generate

electricity.

Biomass includes natural products such as wood,

manure and corn.

These materials are burned and used for heat.

Dams and rivers generate

hydropower.

When water flows through a dam it

activates a turbine, which runs an electric

generator.

GEOTHERMALGEOTHERMAL

Our earth's interior - like the sun - provides heat

energy from nature.

This heat - geothermal energy - yields warmth and power that we can use without polluting

the environment.

Geothermal energy is residual heat of the earth.

The heat from the earth's core

continuously flows outward.

This natural energy heats water trapped

under the ground and releases it as steam or

hot water.

Today we drill wells into the geothermal

reservoirs to bring this hot water to the

surface.

heat of steam from geothermal sources

areas geothermal sources

The hot water or steam can be used directly to cook and warm homes or it can be changed

into electricity.

Steam turns turbine, which turns generatorthat produces

electricity

Nuclear Energy

Well-constructed nuclear power plants

have an important advantage -- they are

extremely clean.

There are, however, significant problems with nuclear power

plants.

Mining and purifying uranium

has not, historically, been a very clean

process.

Improperly functioning nuclear

power plants can create big problems.

Chernobyl scattered tons of radioactive

dust into the atmosphere.

Spent fuel from nuclear power plants is toxic for

centuries, and, as yet, there is no safe,

permanent storage facility for it

Transporting nuclear fuel to and from plants poses

some risk.

These problems have largely stopped the

creation of new nuclear power plants in the United States.

BIOMASS

The term "biomass" refers to any form of

plant or animal tissue.

In the energy industry, biomass refers to wood, straw, biological waste

products such as manure, and other natural materials that contain stored energy.

The energy stored in biomass can be released by

burning the material directly, or by feeding it to micro-organisms that use it to make biogas, a form of

natural gas.

the energy from 2 tons of garbage = 500 lbs of coal

HydropowerHydropower

Hydro means water. So, hydropower is

"water power."

Top hydroelectric plants

Hydroelectric power, a renewable resource, is

generated when hydraulic turbines are turned by the

force of moving water as it flows through a turbine.

The water typically flows from a higher to a lower elevation.

These turbines are connected to

electrical generators, which produce the

power.

Wave energy- water is sent through

channels which makes the waves stronger. The water then turns a turbine.

Solar Thermal Energy

The sun's heat can be used in two

ways

The sun can heat water for domestic hot water systems,

or the sun's light can be concentrated and water

temperatures increased to make steam and electricity.

These solar thermal power plants rely upon

curved mirrored troughs that concentrate

sunlight.

The sun heats a liquid that creates

steam to turn a traditional turbine.

solar panelsin space

WINDENERGY

WINDWINDENERGYENERGY

Wind is created because of different heating of

land and water areas by the sun creating

movement of air from one area to another.

Man has been using the wind to do work

for thousands of years.

The kinetic energy of the wind can be changed

into other forms of energy, either

mechanical energy or electrical energy.

Wind energy has been used for many years to pump water from wells

and grind grains to make flour.

Windmills can be connected to a shaft

which in turn is connected to a generator

to make electricity.

Tidal turbines are similar to wind

machines except itis the tide not the

wind which causesthe blades to turn.They are used in

Europe but are not economical in

the U.S.

NuclearEnergy

Nuclear power plants provide about 17

percent of the world's electricity.

Nuclear power is generated using

uranium, which is a metal mined in various

parts of the world.

Nuclear power stations work in pretty much the same way as fossil fuel-

burning stations, except that a "chain reaction" inside a nuclear reactor makes the

heat instead.

The reactor uses uranium rods as fuel,

and the heat is generated by nuclear

fission.

Neutrons smash into the nucleus of the uranium

atoms, which split roughly in half and release energy

in the form of heat.

This heat turns the water into

steam.

Then the steam drives turbines which drive

generators and produces electricity.

Modern nuclear power stations use the same type of turbines and

generators as conventional power

stations.

If the rods become uncovered by water, deadly radiation is

released into the air and contaminates the area

surrounding the plants for miles.

Nuclear wastecan be storedin caves or inabove groundcement and

metal canisters. The radiation will remain deadly for

thousands ofyears.

Mechanical energy can be transformed

into electrical energy or thermal energy.

Examples include wind turbines

(electrical energy) and refrigerators (thermal

energy).

Electrical energy can be transformed into

mechanical energy (using an elevator) or thermal energy (by

using a space heater).