MUSIC PLAYING
Hi, everyone, I'm Mwaksy. Hey, I'm Greg.So, question, Greg. We use electricity every dayfor different things like powering our lights or our phones,but what exactly is electricity?That is such a good question that we don't often stop and think about.Electricity is a type of energy,and we can easily convert electrical energyinto a different type of energy,like light, or heat, or sound, or movement.That is what makes electricity really usefulfor loads of different things, from lighting our homesto heating water in a kettle to making trains run.I should say, though, that electrical energycan also be really dangerous if it's used in the wrong way,or without the proper safety measures in place.
So like you said,electricity can be used in lots of different ways.But in order to use electricity, first we have to make it. Mm.But how do we make it, Greg? I need you to show me the science.To produce electricity,we use something called a generator.And one of the ways that we're able to generate electricityis with movement.This is called a hand-crank generator.You turn this, and that should generate electricityusing this motor in here,and it's also connected by a wire to a lamp.Do you want to give it a go? Yeah, OK! Go on, then.Oh! It lights up!Yeah! So that's you using movement energyto generate electricity, and it being converted into light energy.Mmm. But I think we can also use that electricityand convert it into sound.So we connect this up…
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Awesome!So that's movement energy, being converted into electricity,being converted into sound energy? Exactly! Wow.If I used a hand-crank all the time to generate all my electricity,my arm would be very tired.So how do we normally generate electricity?OK, well, let's look at a couple of different ways.First up, there are renewable sources of energy.That is a source that does not run out,like solar energy from the sunor movement energy from the wind.The wind turns the blades of a wind turbine,and that movement generates electricity,just like you saw with our hand-crank.Wind turbines are great in windy areas.So, with the hand-crank and the wind turbine,we're using movement energy to generate electricity? Yeah.
OK. Well, what other ways of generating electricity are there?OK, well, you could use non-renewable sources of energylike coal or natural gas.They're called non-renewable because they take millions of years to formand when you burn them, you can't replace them.But also, burning those fossil fuels produces greenhouse gases,and they are not good because they contribute to climate change.When a power station burns fuel, in this case coal,a lot of heat energy is released.That is then used to boil water into steam,and then that moving steam turns a turbineand that generates electricity.So steam is used just like wind turning a wind turbine?Yeah, exactly. And while we are talking about steam,I want to show you another cool waythat steam can be used to generate movement.No, not another cool way - a hot way!Get it? Ha! Steam! Ha-ha! Hot?This is a mug of hot water.If you look closely,you can see steam coming off the top,but we're not going to put our hands too closebecause we don't want to burn ourselves.And this is a cool little gadget called a Stirling engine.I'm going to put it on top, going to see what happens. Ready? Yeah!
MWAKSY GASPS
Greg, this is amazing!Isn't it? Wait, no. How does this work? Tell us.OK. So this works a little bit differentlyto the power station or a wind turbine.This is all about the heat of that steam.It's heating up the bottom of the engine.The top bit is cooler, and that difference in temperaturesets the piston going inside,and that moves this wheel, it's called a flywheel, at the top.Now, what you could then do is use the motion of this flywheelto turn a turbine and generate electricityall using heat energy.Ooh! OK. Now we know what electricity is,I think it is the perfect time to ask them a question.OK.Do you think we could generate all of the electricity we needfrom hand-crank generatorsand the hot steam from hot drinks?Why do you think we might need to use other energy sources too,like wind turbines? Ooh, that's a tricky question.I'm going to get thinking. And so should you! See you soon!Bye! See you!
Video summary
Mwaksy and Greg explore what electricity is, how we generate it using movement and the importance of it in our daily lives.
Having learnt what electricity is, Greg shows Mwaksy how we generate electricity using a hand crank.
After learning about the different ways we can generate electricity, they use a Stirling engine to show how heat can make generators move.
Show Me the Science is a series of short films and teacher resources for primary schools, following presenters Mwaksy Mudenda and Greg Foot as they use demonstrations, experiments and animations to learn about forces and electricity.
Teacher Notes
Before watching the film:
Prior to this lesson you may wish to introduce students to other relevant topics, for example:
During the film:
Depending on your lesson’s focus, you may wish to pause the video at certain points to check for understanding, asking questions such as:
- Apart from electricity, what other kinds of energy are there?
- What is the difference between renewable and non-renewable energy?
- What are other examples of renewable energy? (Solar panels, biomass, hydroelectric and geothermal.)
Final question:
Do you think we can generate all of our electricity using hand crank generators and the hot steam from hot drinks? Why do you think we should use sources like wind turbines to generate electricity?
Discussion points for the final question:
- Would you just use a hand crank to generate electricity for the school? And if so, why?
- How long do you think it would take for a hand crank generator to power a mobile phone?
- We are able to build and place wind turbines in different locations.
- Wind turbines can be used for many years to produce electricity.
- Wind turbines are both scalable and sustainable.
Following on from the film:
Here is a numeracy task you can do which is related to the film and the final question.
- A mobile phone battery uses 5W (5 Watts) of electrical power.
- If a hand crank generator produces 5W in an hour, how many mobile phones could it charge in one hour? (One)
- If a wind turbine produces 50kW per hour, how many phones could it charge in one hour? (A kW is a kilowatt, which is 1000 Watts. Therefore, this wind turbine can charge 10,000 phones in one hour)
This short film is suitable for teaching science at KS2 in England, Wales and Northern Ireland and 2nd Level in Scotland.
How do circuits work? video
Mwaksy and Greg learn about how circuits and switches work, and why they’re so useful.
What are conductors and insulators? video
Mwaksy and Greg create circuits using spoons and dough, to learn about conductors and insulators, why they’re useful and how they keep us safe.
Electricity in the world around us. video
Mwaksy and Greg explore the different reasons why electricity is useful and convert the chemical energy in a battery into different forms of energy.
