Lesson video

So our lesson question today is what is static electricity? And there is a reason that I have included the child with it's hair standing on end and we're going to learn in this lesson what that's got to do with static electricity but hopefully it made you smile before we begin, it definitely made me smile when I saw it.

In this lesson you're going to need an exercise book or a piece of paper, a pencil to write with, a colouring pencil to mark your answers with, we might do a little bit of drawing at the end as well so you might want your colours for that and also a ruler.

These are the star words you're going to need for this lesson, they're all opposites of each other today, you'll see they're all pairs.

So the first pair is attract and repel so I'm going to say it and then you're going to say it, attract and repel.

Great, to attract means to pull something together and repel means to push away.

So you might remember if you've ever studied magnets that magnets can attract and repel, okay.

So, we're going to be using that vocabulary in our lesson today.

We've also got another pair of words, balanced and unbalanced.

So if something's balanced then it means it's equal or the parts are the same size, so for example, at the moment, the fingers on both hands are balanced, there's three fingers on each.

If I only have two fingers on this hand and three on this hand then it becomes unbalanced okay, they're not the same size.

Our next pair of words is positive and negative.

So positive and negative, you might have heard of in your maths lessons in terms of positive and negative numbers okay, we're not going to go too much into the definition today 'cause we're going to be talking about positive and negative charges and I'm going to explain what those are in the lesson.

This is what we are going to be doing today.

We're going to learn what static electricity is, then we're going to have a go at creating static electricity with a balloon.

Then we're going to look at discharging static energy and finally we're going to end the lesson looking at lightning and how lightning works.

To start with I am going to show you a demonstration.

I'm going to show you something with two balloons so I've got one balloon, just hanging from my light on a string, and there's a reason for that.

And then I've got another balloon here.

Now what I'm going to do is I'm going to take both of these balloons, I'm going to rub them, all over my hair and then I'm going to show you something.

Okay.

I'm just going to warn you before I do it that my hair is going to get really messy and I'm going to look a little bit like a cliched mad scientist, okay, so you are allowed to giggle, I give you permission.

However, what's happening to my hair is not really the part of the demonstration that I want you to focus on, okay, so have a little giggle about the hair and then make sure that you're looking at what's happening to the balloons, I will of course explain as we going along, okay.

So I'm going to take both balloons and I'm going to, rub them, quite vigorously, on my hair.

And now, I'm going to leave this balloon hanging, and I'm going to take this balloon and I'm not going to touch them but I'm going to see if I can bring it close to this balloon and you can see, it's actually causing, and they're not touching, I could put my finger through, it's causing this balloon to move, it's repelling this balloon, it's pushing it away.

Not touching but I can make it go round in circles just by moving this balloon about it.

So because I've rubbed the balloons on my hair they're now repelling each other.

And here's a close up of my crazy science hair.

So let's talk about what was happening in that demonstration.

Crazy science hair is coming along for the ride because its going to get even crazier in the next part of the lesson, okay, but before we look at the next part, let's make sure that we understand what was happening in this part.

So, static electricity is the short answer.

But let me explain what static electricity is.

So all matter in the universe, contains positive and negative parts and we call these positive and negative parts charge.

Normally these parts are balanced out.

So they'd be the same number of positive and negative charges in a material, in an object.

But sometimes they can become unbalanced.

So when I rub both balloons on my head, the charges became unbalanced.

So with balloons they had more negative charges, so they're unbalanced, they've got more negative than they do positive.

When those charges are not balanced we say that a static charge has built up.

So after I rub both of those balloons on my head they both had a static charge.

Different materials can have different static charges.

So because balloons are made of rubber they have a negative static charge.

So you can see on the diagram, lots of negative signs, they've got more negative charges once I've charged them.

So that means when I held both of the balloons near each other they would repel, because like charges, the same charges repel.

A bit like, again, when we satisfy magnets, the poles that are the same repel and the poles that are opposite attract, it's the same with charges.

So if we have two negative charges, then they're going to repel each other, so that's what was happening with the balloons.

Not all material gets charged in the same way though.

So if I had taken that balloon and rubbed it on my head and put it near a wall, it wouldn't have repelled, it would have attracted to the wall, okay, the wall is made up of different material.

And so it has a different static charge.

Static charge can be built up in different ways.

So the one way that I showed you, was by rubbing a balloon on my hair but the main way it occurs is just rubbing, two materials or two objects together.

It doesn't always occur but between particular materials and particular objects.

So another example when this can happen is when somebody, when somebody wears socks on a trampoline, now as they bounce the socks and the surface of the trampoline material, that the trampoline's made of, rub together which can make the person who's bouncing become charged.

And this is really noticeable because if they have short hair, then their hair might stand on end just like the little child at the beginning of our PowerPoint, so that little boy must have been jumping on a trampoline with socks in order to get his hair to look like that.

If the hair doesn't stand on end, it might be because it's too long like mine but you might feel a shock when you touch the edge of the trampoline or another person, and that's another sign that you have become statically charged.

We'll talk more later in the lesson about why that shock occurs.

So now I have some questions for you.

What happens to charges to make static charge build up? Just going to give you a hint here with my actions.

Describe one example of how to create static charge.

And how can we tell if a balloon is charged? Pause the video and complete those questions for me now please.

Great, let's check our answers.

So number one, a balloon, sorry an object becomes charged when unbalanced static charge builds up.

Or when the static charge becomes unbalanced okay, that's the key word there, unbalanced charge.

So if you didn't include that that's okay, go back and include it please and if you did, well done, underline it, unbalanced charge, or unbalanced static charge is fine.

Question two, how can we create a static charge.

So you could rub your balloon against your hair, you could rub it against clothing or another soft material or maybe socks on a trampoline.

And number three, how can we tell if the balloon is charged? It will stick to the wall was one option, you also could have written that it would repel another balloon.

Okay so now, in this part of the lesson, we are going to have a go at creating static electricity with a balloon and try out some different things.

You, if you have a balloon at home, in your cupboard maybe, left over from a birthday party, then that's great, you can take part in this demonstration.

If you don't, then don't worry, you can watch me do it, you can still take part in the lesson and maybe next time you go somewhere where there's a balloon, you can have a go at doing these things, so keep them in your memory and try and see if you can build up the static charge and maybe if you're really lucky you could even ask very, very nicely for a parent or carer to try and get you a balloon next time they're in a corner shop and you can have a go with it then.

Okay, we are going to statically charge our balloon again and then we're going to try three different things.

We are going to see what happens to my hair when it's statically charged, when I hold it near by hair.

We are going to see what happens when I hold little pieces of paper near it and we're going to see what happens when I hold it near the wall.

If you have your now balloon and you want to try this yourself, then you can pause the video and you can try those three things now, because it's often more fun to try it yourself than to watch me do it.

However if you do not have a balloon to hand then that's okay, keep watching and you can watch me do it now.

Okay, so remember, to statically charge my balloon, I need to rub it on my clothes or on my hair, for me I think it works better when I do it on my hair.

So I'm going to rub it on my hair and the first thing I'm actually going to show you is what happens when it's on my hair.

So, ooh it didn't actually work that time.

Try this side.

So this works much better with short hair than it does with long hair.

This is just messy, this isn't static charge, this is just because I've been rubbing a balloon on it but what sometimes happens is when the balloon is statically charged, here we go, you can see it more clearly this time, parts of my hair stick to the balloon, they're attracted to the balloon so that means that my hair must have a slight positive charge because we know that the balloon has a slight negative charge.

So you can see, the hair is attached, okay.

Now let's try the second thing.

Let's see what happens when we attach it to some pieces of paper.

So I'm just going to show you under the visualizer.

Okay so I've got these pieces of paper on my desk and watch what happens when I hold my balloon just above them.

They are attracted to the balloon and in fact they even sticking to the balloon, really cool.

So that means these pieces of paper must be positively charged because I know that my balloon has a negative charge.

The last thing I'm going to show you is what happens when we charge the balloon and then hold it to the wall, okay.

So first of all let me show you what happens when the balloon is not charged.

So it shouldn't be charged at the moment.

When I put it against the wall, it falls down the wall.

Quite quickly and it doesn't really make any contact with the wall.

Now I'm going to try my best to show you what happens when I charge the balloon.

But I'm going to warn you before I do it, it's I think, because the rubber on this balloon is not very thick, it's not sticking exactly to the wall like I would like it to, I think because this is quite a low quality balloon, unfortunately the experiment is suffering a little bit.

If you have a thicker rubber, of your balloon, this tends to work better, but we're going to give it a go.

So, charging my balloon up.

And then I'm going to hold it against the wall.

Now it still fell down the wall but what I could see, and what is harder for you guys to see is that instead of kind of falling against the wall and far away from it, it was like skirting down the wall, so it was partly attracted to our wall but maybe if you have a better balloon at home you can give that another go.

Wow, this really is crazy science hair now, what do we think.

Great so, let's write down our observations, what we found while having a go or watching that demonstration.

So I have some sentence stems here for you.

I'd like you to write a sentence that explains what happened when the teacher or yourself, when you held the balloon near your hair, when you held it near small pieces of paper, and when you held it near the wall and let go.

With this one, with number three, if you had a go at home and had a successful try of that then that's great, you can write an honest answer.

For those of us who are writing an answer based on the demonstration that you watched by me, we should be honest as scientists, and it's okay, experiments or demonstrations don't always go to plan so we can say that when we let go, the balloon did fall down the wall but maybe we could say something like, however it stuck closer to the wall than when it wasn't charged or however we would expect it to stick to the wall because it has a positive charge, okay.

Can you pause the video and complete those sentences for me now please.

Great! Now we're going to look at what happens when we discharge static electricity.

So whenever there is a build up of static electricity, sooner or later this build up has to go somewhere.

To make the amount of charge balance out again.

It has to spread to another object.

When it does this, a small, or sometimes large, spark can often be seen.

This is what we call a discharge of static electricity.

Now if that charge jumps to another person they can have a static shock, so you might have experienced that before, where you've felt like a random little shock when you've touched someone or touched an object or maybe like the example we learnt earlier, you've been jumping on the trampoline in your socks and then you can static charge someone.

Okay, so now you know why that happens.

Sometimes the shock is so small and quick that we might not see it, but it is there.

And I had a friend actually, growing up, when I was your age, who had a trampoline at their house and when I used to go round to play they used to try on purpose to charge themselves up by wearing socks on the trampoline and then they would play shock it with me, so they'd try and, if you got the static shock then you were it.

It doesn't hurt, it was actually quite a lot of fun but I didn't really understand the science behind it at the time and now I do and now hopefully you do too.

There are a number of examples of when this kind of static charge can build up and be discharged in our normal life.

So we've talked about the trampoline and another example is when you walk on the carpet in socks the socks might rub on the carpet which will build up charge and then when you touch a metal object, like a door handle, the charge will jump from you to the door handle which gives you a shock.

So that might be something you've experienced before as well.

Another one that you might of seen or heard around your house is if you have a tumble dryer so a machine that dries your clothes, sometimes when the clothes are tumbling, rolling round in there, they're rubbing past each other and so static charge is building up and then when you take them out you can hear like a crackling sound which is the static charge being discharged, okay.

So when we rub two items together the charge builds up and builds up but eventually it needs to be discharged, that means it needs to pass from one object to another and this is so the charges can balance out again.

When that happens we often get a little shock or we can see a little spark.

Can you please pause the video and have a go at answering these questions for me.

What happens to charge when static discharge occurs? And give two examples where static discharge may occur.

Remember if at any point you think, I can't remember what Miss.

Simkin just said, that's okay, 'cause you can just go back to the video and watch that bit again.

Pause the video and complete these questions for me now please.

Great, let's check our answers.

So for number one you might of written an answer like this.

Charge spreads to another object, or maybe charge moves to another object and balances out again, okay, it's important that you have those two points, that it's moving somewhere else and that it's balancing out again.

If you wrote those you can underline them and give yourself a tick, if not that's okay, just pause the video and add them in for me.

You might also have said, when it does this a small spark can be seen.

That's some extra information, that is also correct.

And number two, what examples do we know, well there are lots but some of the ones you could have written were, clothes that have been in a tumble dryer or touching a metal door handle after walking on the carpet in socks.

You might have also written about our trampoline example.

Lightning, this brings us to the last part of our lesson.

So, lightning is the most famous example of a discharge of static electricity.

So, not only are small things, like that little shock you sometimes get when you touch a door handle, caused by static electricity, but also this huge weather phenomenon which we see when there are storms, lightning is caused by the same thing, it's caused by static electricity.

Okay, and what is happening is that the particles in the clouds, are rubbing together and over time this causes a build up of charge.

As the charge builds more and more and more, eventually a huge amount of charge has built up and it needs to discharge.

So this discharge is when you see lightning.

It's when that charge is jumping from the clouds to the ground.

And that spark is the lightning that you see.

That discharge is also what cause thunder, the sound.

So lighting is what we call the spark that we can see and thunder is what we call the spark that we can hear, they're actually the same thing but because lighting is so far away and light and sound travel at different speeds, we often hear the thunder at a different time then we see the lighting but they're actually caused by the same thing.

So you can supposedly tell how far away a lighting strike is from you if you count the difference between when you see the lighting and how many seconds and when you hear the thunder.

So you can try that next time there's a storm.

Our last exercise for this lesson is that I'm going to ask you please to add annotations to this diagram below, so you'll have to draw your own version, to describe what happens when there is a lighting strike.

So, you might want to draw a lighting strike in and you want to add some labels that describe, so what's happening in the clouds, what's happening when the lighting is discharged, what are we hearing, those kinds of things.

Pause the video and have a go now please.

Great so yours might have looked a little bit like mine.

You might also have different labels but let's see if you got something similar.

So I put, particles in the clouds rub against each other causing a build up of charge.

So the key points there are rubbing against and that build up of charge.

Then, I put another arrow next to the cloud which is saying the charge builds up and builds up so it keeps building up.

And then the charge jumps from the cloud to the ground.

I've actually missed quite a key word there which hopefully you included which is discharge.

That's what this section is about.

So you could say, the charge is discharge, which means it jumps from the clouds to the ground and I've got my lighting strike in there.

You might also have included a label about thunder if you're being very conscientious and hard-working.

If you need to add anything to your diagram, pause the video and do that for me now please.

Great so that brings us to the end of our lesson.

We learnt all about static charge today.

We learnt that charge can be either positive or negative and normally it's balanced but if you rub two objects together it might become unbalanced and this means that an object is statically charged.

And then it can either attract or repel objects depending what their charge is.