Transcript What is energy?

Introduction to energy
Energy is everywhere.
We use energy to run in the playground, to
bake a cake, and to read a book.
We use energy for everything. In fact, you
are using energy right now!
If energy is all around us, and we use it all
the time, who can explain what energy is?
Once we can explain what energy is,
we will know why it is important
to save energy. So let’s get started!
What is energy?
Take a look around you.
Everything in the room is using energy.
Some things use energy in an obvious way, such
as the lights in the room using electrical energy
to make the room bright.
Other things don’t look like they are using energy
at all – such as your desk or your chair.
So what does energy do?
What does energy do?
Energy causes things to happen around us.
This is often described as the ability to do
work.
Work can be:
• Movement
• Sound
• Light
• Heat
• Electricity
• And more!
Let’s look at the examples from before.
Energy is the ability to do work
This fan has the ability to move air
around the room to cool you down.
(Moving energy = Kinetic energy)
This chair has the ability to fall
over if you keep leaning on it!
(Stored energy = Potential energy)
This paper plane has the ability to fly
around the room and land on your
friends desk.
(Moving energy = Kinetic energy)
Forms of energy
To understand how energy works, we need to learn
about the different forms (also known as types or
kinds) of energy.
Potential
There are two main types of energy:
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moving energy (kinetic energy), and
stored energy (potential energy).
Kinetic
Can you point out which of these eggs has
kinetic energy and which has potential energy?
Kinetic (moving) energy
Everything that is moving uses kinetic energy.
This bike uses
kinetic energy to
spin its tyres.
This bird uses kinetic
energy to fly!
This snail uses kinetic
energy…very slowly.
Potential (stored) energy
A slinky has stored (potential) energy.
It is ‘waiting’ to fall down the stairs.
Once it starts to fall, the potential
energy will change into kinetic energy
and the slinky will move down the
stairs.
There are many other forms of energy
as well.
Sound energy
Sound energy is what you hear!
These speakers use sound energy to
send music to your ears.
Birds use sound energy to sing, and
teachers use sound energy to tell you
all about…sound energy!
Chemical energy
Chemical energy is stored in
batteries.
It is also stored in food, but
these chemicals are healthy
chemicals that give us
energy!
All living things use chemical
energy , including people.
Electrical energy
Electrical energy is what we call
electricity.
Everything that uses electricity is
using electrical energy.
Have a look around the room,
can you name five things that
are using electrical energy right
now?
Heat energy
Heat energy gives us warmth.
Anything that is hot, uses heat energy.
When it is cold outside we use heat energy from
the heater to keep us warm.
When we want toast, we use heat energy from
the toaster to toast our bread.
When we want cupcakes we use heat energy
from the oven to bake our cupcakes!
Forms of energy
And that’s not all, there is also nuclear,
gravitational, mechanical…the list goes on!
Luckily, you don’t need remember every form of
energy that exists, but something you should try
to remember about energy is this:
Energy cannot be created, and
Energy cannot be destroyed!
So, how do we use energy if we can’t create it?
We change it.
This is known as transforming and transferring.
Transferring energy
Imagine a boiling kettle. Is it hot or cold?
Very hot.
If you wanted to pick up the kettle would you pick it up
by putting your bare hands on the sides of the kettle?
No. Why not?
Because it would burn your hands. Why would it burn
you?
Heat energy was used to boil the water in the kettle. That
heat energy can move very quickly (transfer) from one
object to another.
If you touched the kettle the heat energy would transfer
from the kettle to your bare hands – ouch!
Transforming energy
Not only can energy move from one
object to another, it can also change from
one form to another.
This is called, transforming energy.
To help you remember this word, you
might like to think of a Transformer,
‘transforming’ from a car into a robot.
Energy is transformed all the time. When
we turn on a light switch, energy
transforms from electrical energy, to light
energy.
Example of transformation
In this example, the electrical energy is
transformed into heat energy.
Electrical energy
Heat energy
The heat energy turns our bread into
toast.
Can you think of another example of
energy transforming from one form to
another?
Where do we get our energy from?
Do humans have energy?
Of course!
Where do we get our energy from?
Food!
All food gives us energy. Some food gives us a lot of
energy (like a banana) and other food gives us a little bit
of energy (like potato chips).
Where does food get its energy from?
Food receives its energy from the sun. This is chemical
energy.
Sources of energy
A source of energy is where
we get our energy from.
Wind
Solar
Biomass
Coal
Hydro
We can use these sources to
help us produce energy.
Food
Nuclear
Natural Gas
Here are some examples of
sources of energy:
Oil
Renewable and Non-Renewable energy
There are many sources of energy in the world.
These sources are divided into two types:
• Renewable sources, and
• Non-Renewable sources
Did you know that ‘re’ means again?
So, re-new-able = again-new-able. Which means,
things that are able to become new again.
What do you think Non-Renewable might mean?
That’s right! Not able to become new again.
Renewable and non-renewable
Which of the following two energy sources do you think is renewable?
HINT:
Is the light energy from the sun able to shine every day?
ANSWER: Yes.
Solar = Renewable
Solar
HINT:
If we dig up all of the coal from under the ground, will more coal
form quickly so we can use it again?
Coal
ANSWER: No.
Did you know, it takes millions of years for coal to form?
Coal = Non-Renewable
Which of these sources of energy are renewable?
Wind
Hydro
Solar
Nuclear
Biomass
Oil
Coal
Natural Gas
Renewable energy sources
Solar
Biomass
Hydro
Wind
Which of these sources of energy are NON-renewable?
Wind
Hydro
Solar
Nuclear
Biomass
Oil
Coal
Natural Gas
Non-renewable energy sources
Nuclear
Oil
Coal
Natural Gas
How are coal, oil and natural gas formed?
Coal, oil and natural gas are all made from the
same thing! Can you guess what?
Decomposed plants.
Think about the plants that were around when
dinosaurs were roaming the Earth millions of
years ago.
Over millions of years, these plants
decomposed in swamps and turned into solids
(coal), liquids (oil) and gases (natural gas).
Coal
Oil
Natural Gas
Powering our homes and schools
How do we get energy into our homes?
Have you ever noticed the power lines that connect
your house to the other houses in your street?
Power lines send electricity (electrical energy) to our:
• Homes
• Schools
• Streets
• Offices
• Shopping centres and more…
Where does the electricity come from?
Power Stations
A power station is a large factory that makes
electricity.
Power stations use coal to make electricity.
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•
•
•
•
They burn the coal to make fire
The heat from the coal fire boils water
The steam from the water moves a turbine
The turbine spins a generator
The generator transforms kinetic (moving)
energy into electricity!
What does burning coal do to our environment?
When we burn coal, it releases a greenhouse
gas called carbon dioxide (CO2).
When there is a lot of carbon dioxide in the
atmosphere, it traps in the heat from the
sun.
This heat makes the atmosphere warmer
than it should be.
This is known as enhanced global warming.
Where does coal, oil and natural gas come from?
We get the coal, oil and natural
gas from the ground.
There is a finite amount coal, oil
and natural gas in the ground,
which means – it will run out one
day. It is non-renewable.
Luckily, we don’t have to use coal,
oil and gas to make electricity.
We can use renewable resources
instead.
Solar (sun) energy
The word solar, means sun.
When we talk about solar energy, we are talking
about energy from the sun – in particular light
energy.
To catch the light energy from the sun, we use
solar panels.
The light energy hits the solar panels and is
transformed into electrical energy.
The solar panels have an inverter in them, which
converts the electrical energy into electricity
that we can use in our homes.
When we talk about wind energy, we are
talking about the kinetic (moving) energy of
the wind.
When the wind moves past a wind turbine,
the kinetic energy moves the turbine’s blades
and makes them spin.
The wind turbines have a generator in them
which transforms the kinetic energy into
electrical energy.
Hydro (water) energy
The word hydro, means water.
When we talk about hydro energy, we are
talking about kinetic energy from moving
water.
When water rushes down the wall of the
dam, it pushes past and spins a turbine.
The turbines have a generator in them which
transforms the kinetic energy into electrical
energy.
How much renewable energy do we use?
Australia currently uses non-renewable sources of
energy for 95% of our energy needs.
Only 5% of our energy is generated using renewable
energy such as solar, wind and hydro.
In the future, renewable energy sources will be used
much more often, as we will need an energy source that
does not run out.
In the mean time, as we are using non-renewable energy
sources, it is important to use our energy efficiently.
Energy efficiency
When we talk about energy efficiency, we are
talking about using less electricity.
Saving electricity helps to reduce our energy bills,
but it also reduces the amount of non-renewable
energy sources needed to supply us with energy.
The fewer non-renewable sources of energy we
use, the healthier our planet will be.
So, what can we do to use less energy?
Stand-by Power
The first, and easiest thing you can do, is to turn off
any electrical items that you are not using at the
wall.
Did you know, that when you turn a TV (or any
other electrical item) off at the screen, you are
putting it on stand-by.
This means it is not really ‘off’, it is just standing by
waiting to be turned on again.
This uses a lot of energy.
To turn off your appliances completely,
you need to turn them off at the wall.
Be an energy superhero!
It’s easy to be an energy superhero, all you need to
remember is to:
• Turn off anything you are not using : that
includes lights, Gameboys, Nintendo's, TV’s and
stereos – anything that uses electricity!
• Put on a jumper instead of turning on the
heater straight away when you are cold.
• Swap your light globes for energy efficient light
globes at home, and at school.
• Close doors and windows when you are heating
or cooling a room.
• Tell everyone at school what you have learnt
about energy! And be wise about energy!