Energy and Its Forms

Describe the relationship between work and energy.

Relate kinetic energy to mass and speed. Analyze how potential energy is related

to an object’s position and give examples of gravitational and elastic

potential energy. Give examples of the major forms of

energy and explain how each is produced.

In an avalanche, a mass of loose snow, soil, or rock suddenly gives way and slides down the side of a mountain.The avalanche releases a great amount of energy.

Energy and Work Work is done when a force

moves an object through a distance.

Energy is the ability to do work. Energy is transferred by a force

moving an object through a distance.

Work is a transfer of energy.

Energy has different forms. A. The sun gives off energy in the form of

heat and light. B. Plants convert sunlight into food. C. People convert food energy into muscle

movement.

Energy and Work

EnergyMany forms of energy can be

classified into two general types:

Kinetic EnergyPotential Energy

Kinetic EnergyThe energy of motion is

called kinetic energy.

The kinetic energy of any moving object depends

upon its mass and speed.

Potential EnergyPotential energy is energy that is stored as

a result of position or shape.

Two forms of potential energy are:Gravitational potential

energyElastic potential energy

Gravitational Potential Energy

Potential energy that depends upon an object’s height is called gravitational

potential energy.An object’s gravitational potential energy depends on its mass, its

height, and the acceleration due to gravity.

This type of potential energy increases when an object is raised to a higher

level.

This diver has gravitational potential energy as she stands at the end of a diving

board. She gained the

potential energy by doing work—by

climbing up the steps to the diving board.

Potential Energy

Place two items at different heights…WHICH DO YOU THINK HAS MORE

POTENTIAL ENERGY? WHY?Gravitational PE depends on an objects height. GPE increases when an object is

raised to a higher level.GPE depends on the mass of something, its height, and the acceleration due to gravity

(g).

Gravitational Potential Energy

When this musician pulls the string of her cello to one side, the

string is stretched and gains

potential energy.

Potential Energy

Elastic Potential EnergyThe potential energy of an object that is stretched or compressed is known as elastic potential energy.

EX: springs, guitar strings, bike shocks

The musician adds energy to the cello string by plucking it.

The energy stored in the stretched string is potential energy.

The stored energy is converted into kinetic energy when the string is

released and it vibrates.

Elastic Potential Energy

All energy can be considered to be one of three forms:

Kinetic energy, Potential energy, andenergy in fields such as those produced

by electromagnetic waves.

Each of these forms of energy can be converted into other forms of

energy.

Forms of Energy

Forms OF ENERGYMechanical

Electromagnetic Electrical Chemical ThermalNuclear

What is Mechanical Energy?

Energy due to a object’s motion (kinetic) or position (potential).

The bowling ball has mechanical energy.

When the ball strikes the pins, mechanical

energy is transferred to the pins!

Examples of Mechanical Energy

Mechanical Energy

Not limited to machines.

Mechanical energy is the sum of an object’s PE and

KE.

What is Thermal Energy? Thermal energy = Heat energy

The heat energy of an object determines how active its atoms are.

A hot object is one whose atoms and molecules are excited and show rapid

movement.

A cooler object's molecules and atoms will show less movement.

What is Chemical Energy? Energy that is available for

release from chemical reactions. The chemical

bonds in a matchstick store

energy that is transformed into thermal energy when the match

is struck.

Examples of Chemical EnergyWhen bonds

are broken, the released

energy can do work. All chemical

compounds, including fuels such as coal and gasoline, store energy.

This family is using the chemical energy of burning wood to produce thermal energy for heating marshmallows.

Forms of Energy

What is Electrical Energy? Energy

associated with electric charges.

Easily transported

through power lines and

converted into other forms of

energy

What is ElectromagneticEnergy?

Light energy or energy that travels through space

in the form of waves.

Includes energy from gamma rays, xrays,

ultraviolet rays, visible light, infrared rays,

microwave and radio bands

Lightning bolts transfer electric charge.

Galaxies are giant structures in space

that typically contain billions of stars. The

stars give off enormous amounts of

electromagnetic energy.

Forms of Energy

The nucleus of an atom is held together by strong and weak nuclear forces, which can store an enormous

amount of potential energy. The energy stored in atomic nuclei is

known as nuclear energy. Nuclear fission releases energy by splitting

nuclei apart. Nuclear fusion releases energy when less massive nuclei combine to form a more

massive nucleus.

Nuclear Energy

QUIZ TIME!What type of energy

cooks food in a microwave oven?

ELECTROMAGNETIC ENERGY

What type of energy is the spinning plate

inside of a microwave oven?

MECHANICAL ENERGY

QUIZ TIME!What energy

transformation occurs when an electric lamp is

turned on?ELECTRICAL ENERGY

ELECTROMAGNETIC

ENERGY

QUIZ TIME!Electrical energy is

transported to your house through power lines.

When you plug an electric fan to a power outlet,

electrical energy is transform into what type

of energy?MECHANICAL ENERGY

What types of energy are shown below?

Mechanical and Thermal Energy(Don’t forget friction)

What types of energy are shown below?

Electrical, Mechanical andElectromagnetic Energy

What type of energy is shown below?

Chemical Energy

What type of energy is shown below?

Thermal Energy

Draw a diagram showing the flow of energy transformations in a car from starting the vehicle to driving. You

should have 5 different types of energy.

Energy Transfer

Chemical

Electrical

Electric

al

Electrical

Sound(mechanical)

Light(Electromagnetic)

ThermalMechanical

Tomorrow… How do you know

what you know?

Energy of motion.Kinetic energy of a moving object depends upon its mass and its speed.

K.E. = m x v2

2

Kinetic Energy

Energy due to position or stored energy.

Gravitational Potential Energy (G.P.E)

G.P.E = Wt. x Ht.

Potential Energy

Energy is never created or destroyed.

Energy can be converted

from one form to another but

the total energy remains

constant.

Law of Conservation of Energy