EnergyEnergy

What is energy?

• Energy makes things happen• For example energy makes sounds, allows

objects to move and work, destroys things (like the tornado on the last page)

• The Law of Conservation of Energy states that:• Energy can not be created or destroyed, but it Energy can not be created or destroyed, but it

is changed from one form to anotheris changed from one form to another• Why do we need replace batteries then?Why do we need replace batteries then?

Forms of energy:

• There are lots of different types of energy• They are measured in Joules • We need energy to move, this comes from

food and food contains chemical energy• This chemical energy also keeps our body

temperature at 37°Celcius• Chemical energy can be changed into

movement (kinetic) and heat energy

Chemical Energy• When we eat we put food

(chemical energy) into us • This energy can be stored as

fat or used by our body• Batteries also contain

chemical energy• Petrol, diesel, coal, wood

and gas all have stored chemical energy

Electrical Energy

• Electrical energy usually flows through wires

• Chemical energy from a battery is converted into electrical energy in the wires

• It can also occur as static e.g. lightning

Gravitational Potential Energy

• At the top of this roller coaster the cars stop for a split second

• At this point they have Gravitational (potential) energy

• Gravity will pull the cars down again (they will have kinetic energy)

Elastic Potential

• The string of the cross bow has elastic energy when it is pulled back

• When released this elastic energy is changed into kinetic and sound energy

Kinetic Energy• This is movement energy• Our muscles produce the movement• Car engines do the same• When we move we produce heat

Sound Energy

• Sound energy is created by;1. objects hitting the ground with a “thud”2. arrows flying though the air with a “woosh” 3. bullets fired from guns making a “bang”4. People taking5. Objects vibrating e.g. drum skins, guitar

strings etc.

Light Energy

• Light is the fastest form of energy known to man

• It takes 8 minutes to travel from the Sun to the Earth

• The suns energy is called Solar energy• Light energy can be used by solar panels to

make electricity

Thermal Energy

• Thermal means heat• All machines (and animals are machines to a

scientist) are not perfect• They waste chemical energy usually turning it into

heat energy, this escapes into space (space is gradually getting a little warmer)

• When we run we convert chemical energy from food into movement energy, but we also get warm and this waste heat escapes into the air and then into space

Energy Transfer

• Energy can be changed into different types e.g.

• A torch

Chemical energy

Light energy

Heat energy

Non Renewable Energy

• Non renewable means cannot be renewed• In other words this energy will run out• Fossil fuels are the main sources of non-renewable

energy• These are:1. Coal2. Oil 3. Natural Gas• Nuclear fuels are also non-renewable

Renewable Energy

• These types of energy can be renewed• This means that they can be used again and

again• Examples include:• Solar• Hydroelectric• Wind• Tidal

Solar Power• Solar panels change light energy into

electrical• What are the advantages and disadvantages of this type of

energy?

A Solar Farm Solar Power Cars

Wind Energy

• Wind turbines convert wind energy into electrical

• Why is there so much opposition to wind farms?

A Wind Farm in Palm Springs

Hydroelectric Energy

• Potential energy of the water in the reservoir is converted kinetic energy in turbines then into electrical energy

• This is the Hoover dam in the USA

Biomass

• This is living or decomposing matter that can be used for fuel e.g.

• Wood chips and branches • Cars can be run on bio-fuels

either alcohol (fermented from corn) or oil (vegetable oil)

The Koenigsegg CCXR Edition runs on alcohol fuel

Geothermal Energy

• The Earth is hot under the surface• This heat can create geysers of hot water and

it can be used to make electricity or heat homes

New Technology

• Formula 1 cars have used the kinetic energy from braking to generate more electricity

• Modern electric cars also use this regenerative braking

• The Tesla Roadster is an electric car with this braking

The Tesla Roadster