introduction to energy energy is everywhere. we use energy to run in the playground, to bake a cake,...
TRANSCRIPT
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 importantto save energy. So let’s get started!
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 is energy?
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.
What does energy do?
This fan has the ability to move air around the room to cool you down.(Moving energy = Kinetic energy)
This paper plane has the ability to fly around the room and land on your friends desk. (Moving energy = Kinetic energy)
This chair has the ability to fall over if you keep leaning on it!(Stored energy = Potential energy)
Energy is the ability to do work
Forms of energy
To understand how energy works, we need to learn about the different forms (also known as types or kinds) of energy.
There are two main types of energy:
• moving energy (kinetic energy), and• stored energy (potential energy).
Can you point out which of these eggs has kinetic energy and which has potential energy?
Potential
Kinetic
Everything that is moving uses kinetic energy.
Kinetic (moving) energy
This bird uses kinetic energy to fly!
This bike uses kinetic energy to spin its tyres.
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 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.
Chemical energy
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, andEnergy 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.
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!
Transferring energy
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.
Heat energy
Electrical energy
Example of transformation
In this example, the electrical energy is transformed into heat energy.
The heat energy turns our bread into toast.
Can you think of another example of energy transforming from one form to another?
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.
Where do we get our energy from?
A source of energy is where we get our energy from.
Here are some examples of sources of energy:
We can use these sources to help us produce energy.
Sources of energy
Solar HydroWind
Biomass
OilNatural GasCoal
FoodNuclear
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 energy
Which of the following two energy sources do you think is renewable?
Renewable and non-renewable
Is the light energy from the sun able to shine every day?
If we dig up all of the coal from under the ground, will more coal form quickly so we can use it again?
HINT:
HINT:Solar
Coal
ANSWER: Yes. Solar = Renewable
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?
Solar HydroWind
BiomassOil
Nuclear
Coal Natural Gas
Solar HydroWind
Biomass
Renewable energy sources
Which of these sources of energy are NON-renewable?
Solar HydroWind
BiomassOil
Nuclear
Coal Natural Gas
Non-renewable energy sources
Oil
Nuclear
Coal Natural Gas
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).
How are coal, oil and natural gas formed?
Coal Oil Natural Gas
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?
Powering our homes and schools
A power station is a large factory that makes electricity.
Power stations use coal to make electricity.
• 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!
Power Stations
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.
What does burning coal do to our environment?
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.
Where does coal, oil and natural gas come from?
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.
Solar (sun) energy
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!