Energy and Energy Resources

Carin Miranda

Smyrna Middle School

Fall 2009

What is Energy?

• Energy is the ability to do work.

• Energy is expressed in joules (J).

Kinetic Energy

• Kinetic Energy is the energy of motion.

• Kinetic Energy = mv2 / 2

Potential Energy

• The Energy an object has based on shape or position.

• Elastic potential energy– When you change the shape of something

• Gravitational potential energy– The higher something is off the ground the higher its

potential energy. The more it weighs the higher its potential energy as well. Depends on height and weight.

• Chemical potential energy– The food you eat is stored as chemical potential energy

Mechanical Energy

• Is the total amount of energy in a system.• Mechanical energy= potential energy + kinetic energy

• As kinetic energy goes up potential goes down and vice verse.

Other Forms of Energy

• Thermal

• Chemical

• Electrical

• Sound

• Light

• Nuclear

Thermal Energy

• Heat

• Higher the temperature the faster the molecules move

• The more you have of a substance the more thermal energy you have.

Chemical Energy

• Food you eat

• Batteries

• Anytime you have something breaking down and it creates a new object.

Electrical Energy

• Moving electrons

• Anything you plug in.

• Batteries start as chemical energy but it is converted into electrical energy.

Sound energy

• Caused by an objects vibrations

• Anything you hear

Light Energy

• Vibrations of electrically charged particles

• Anything you see.

• Waves that you can’t see– Radio, Gamma, ultraviolet, microwaves

Nuclear Energy

• When two atoms fuse together(fusion) or split apart (fission)

• Fusion happens in the sun

• Fission happens when uranium is split to produce electrical energy

Energy Conversions

• A change from one form of energy to another.

• Any form of energy can be converted into any other form of energy.

Energy Conversions in Plants

• The nuclear energy of the sun produces light and thermal energy.

• The light energy from the sun is converted by plants into chemical energy which is stored in the foods we eat.

Conservation of Energy

• Roller Coaster- Highest potential energy is at the top of the biggest hill. Highest kinetic energy is at the bottom of the biggest hill.

Law of Conservation of Energy

• Energy can never be created nor destroyed.

• It can only be transferred or converted.

• In every energy conversion some thermal energy is given off due to friction.

• This means that there is no such thing as a perpetual motion machine.

Energy Efficient?

• The amount of energy available before a conversion compared to the amount of useful energy after a conversion.

Energy Resources

• A natural resource that can be converted into other forms of energy

• Nonrenewable– Cannot be replaced or are replaced at a slower

rate than we are using it.

• Renewable– Can easily be replaced.

Nonrenewable Resources

Fossil Fuels

• Includes coal, natural gas, petroleum.

• Most coal is used to generate electrical energy.

Nuclear Energy

Uranium 1 uranium= 1 metric ton of coal.

Renewable

• Solar

• Water (Hydroelectric)

• Wind

• Geothermal (hot water under ground)

• Biomass (trash)

Advantages vs. Disadvantages

Know all the advantages and Disadvantages of the Energy

Resources on Page 368