Energy

Energy: Forms and Changes

Nature of Energy

• Energy is all around you!– You can hear energy as sound.– You can see energy as light.– And you can feel it as wind.

Nature of Energy

• You use energy when you:– hit a softball.– lift your book bag.– compress a

spring.

Nature of Energy

Living organisms need energy for growth and movement.

Nature of Energy

• Energy is involved when:– a bird flies.– a bomb explodes.– rain falls from the sky.– electricity flows in a

wire.

Energythe ability to do work

Energy comes in many forms:mechanical, electrical , magnetic, solar,

thermal, chemical, etc...

The SI unit of energy is the Joule.

Energy

Energy

Potential EnergyStored energy and the

energy of position

Kinetic EnergyMotion of waves, electrons,

atoms, molecules, and substances

Potential EnergyStored energy and the

energy of position

Chemical EnergyEnergy stored in the bonds of

atoms and molecules

Elastic EnergyEnergy stored in objects by the

application of force.

Nuclear EnergyEnergy stored in the nucleus of an atom – the energy that holds the

nucleus together

Gravitational EnergyEnergy of place or position

Potential EnergyStored energy and the

energy of position

Kinetic EnergyMotion of waves, electrons, atoms, molecules, and

substances

Kinetic EnergyMotion of waves, electrons, atoms, molecules, and

substancesElectrical

EnergyMovement of

electrons

Mechanical MotionMovement of substance from

one place to another

Sound EnergyMovement of energy through substances in longitudinal waves

Radiant EnergyElectromagnetic energy that travels in transverse waves

Thermal EnergyInternal energy in substances – vibration or movement of atoms and molecules in

substancesa.k.a. “heat”

Potential EnergyStored Energy

gravitational potential energy

GPE = mgh m - mass of object in kg g - acceleration of gravity in m/s2

h - height of object, in m, GPE – gravitational potential energy in J

Kinetic Energyenergy of motion

All moving objects thathave mass have kinetic energy.

KE = 1/2 mv2

m - mass of the object in kgv - speed of the object in m/sKE - the kinetic energy in J

Different Types of Energy.

Kinetic Energy

Anything that moves has kinetic energy.

Gravitational Potential Energy (GPE)Anything above the ground has gravitational potential energy i.e. anything that can fall, like ski jumpers, aeroplanes and climbers.

Nuclear Energy

Released only from nuclear reactions The sun and all of the stars. Hydrogen bomb (Fusion)Nuclear power plants

Sound EnergyAnything noisy gives off sound energy like vocal chords, speakers and instruments.

Chemical Energy

Anything with stored energy which can be released by a chemical reaction has chemical energy, things like food fuels and batteries.

Radiant Energyalso called electromagnetic energy

All life on Earth depends upon radiant energy from the sunExamples: radio waves, microwaves, X-rays,

Heat/Thermal Energy

Anything with a temperature above absolute zero (-273°C) has heat energy. That means everything has some thermal energy.

Light EnergyAnything luminous gives off light energy, like the sun, light bulbs , candles and glow worms.

Electrical Energy

Electrical energy is very useful, because its easily converted into other forms – wherever there's a current flowing there's electrical energy.

Elastic Energy Anything stretched, has elastic energy – things like rubber bands, springs, knickers, elastic etc

There are 9 types of energy hidden in this pictureCan you find them?

Can you think of examples of each type of energy?

There are many different types of energy:

thermallightsoundelasticgravitationalkineticelectricalchemicalnuclear

Different types of energy

Which type of energy?

Energy can be changed from one form to another.

For example:Chemical energy in food is

converted to thermal energy and kinetic energy by our bodies.

Energy transfer

What other energy transfers can you think of?

Gravitational energy in a ball is converted to kinetic energy when it falls to the ground.

burning match portable torch microphone radio television catapult mobile phone

car

Describe energy transfer in each device

burning match portable torch microphone radio television catapult mobile phone

car

chemical to thermal and lightchemical to thermal and lightsound to electricalelectrical to sound and thermalelectrical to sound and light and thermalelastic to kinetic and thermalchemical to sound and microwaves(EM radiation) and thermalchemical to kinetic and sound and thermal

In all these transfers the energy is not lost, it is conserved. Energy cannot be destroyed or created.

Describe energy transfer in each device

Draw an energy transfer for... YOU!!

ChemicalHeat

Kinetic (movement)

Sound

Energythe ability to do work

Energy comes in many forms:mechanical, electrical , magnetic, solar,

thermal, chemical, etc...

The SI unit of energy is the Joule.

Energy

Energy

Potential EnergyStored energy and the

energy of position

Kinetic EnergyMotion of waves, electrons,

atoms, molecules, and substances

Potential EnergyStored energy and the

energy of position

Chemical EnergyEnergy stored in the bonds of

atoms and molecules

Elastic EnergyEnergy stored in objects by the

application of force.

Nuclear EnergyEnergy stored in the nucleus of an atom – the energy that holds the

nucleus together

Gravitational EnergyEnergy of place or position

Potential EnergyStored energy and the

energy of position

Kinetic EnergyMotion of waves, electrons, atoms, molecules, and

substances

Kinetic EnergyMotion of waves, electrons, atoms, molecules, and

substancesElectrical

EnergyMovement of

electrons

Mechanical MotionMovement of substance from

one place to another

Sound EnergyMovement of energy through substances in longitudinal waves

Radiant EnergyElectromagnetic energy that travels in transverse waves

Thermal EnergyInternal energy in substances – vibration or movement of atoms and molecules in

substancesa.k.a. “heat”

Potential EnergyStored Energy

gravitational potential energy

GPE = mgh m - mass of object in kg g - acceleration of gravity in m/s2

h - height of object, in m, GPE – gravitational potential energy in J

Potential EnergyStored Energy

gravitational potential energy

GPE = Wh W – Weight of object in N h - height of object, in m, GPE – gravitational potential energy in J

Roller Coaster Conversions

The NEED Project

The NEED Project

Energy pokerLook at the scenes on the slides that follow. Make a bid for the number of energy transfers that you can see. The person with the highest bid has to explain where they are. If they fail to find that number they lose.Can you win at energy poker?

Let’s look at a couple of examples first…

First Example…

Energy poker score: 1Sunlight energy converted into heat to boil the water for tea

Energy poker score: 3Chemical energy in fuel converted to movement, heat and sound

Second Example…

Now for the real thing… make a bid for the number of energy transfers that you can see!