Lesson video

Hi, my name's Mr. Brown.

Welcome to today's lesson.

We are going to be looking at circuits and we're going to be looking at switches and we're gonna be thinking about electrical safety as well.

There's lots to cover.

So let's have a look at the learning objectives for today, the learning outcomes, the lesson cycles, and the keywords.

Today's learning outcome is to make a switch for an electrical circuit.

Here are the keywords for today.

So the first keyword is circuit, and a circuit is a loop of connected electrical components that let electricity flow through them.

We'll be going through this in much more detail throughout the lesson.

A series circuit is a type of circuit and that is a complete loop that goes from one side of the battery to the other in one continuous loop.

A zinc-carbon cell, we're gonna be talking about different types of cells, but this is one type of cell, a zinc-carbon one.

And this is a component that makes electricity using a chemical reaction.

And lastly, a switch.

A switch controls the flow of electricity by completing or breaking a circuit.

And we'll be talking about all of these keywords throughout today's lesson.

Today's lesson outline, we've got two learning cycles.

The first learning cycle is about safe electrical circuits, and the second learning cycle is about switches in simple circuits.

We're going to start with safe electrical circuits as part of our lesson cycle one.

We're going to be talking about an electrical circuit.

We've defined what an electrical circuit is within the keywords, and they often contain different components.

Now, the picture that you've got here, we're gonna go through the different components that you might find in a school classroom.

You might have something different, but these are just examples of what's commonly found in classrooms.

We have a battery pack, they can come in different shapes and sizes.

These ones are for a certain type of battery called AA, and there's enough for two AA batteries, which you can see in the second one.

Now, this battery pack has got zinc-carbon cells in it.

So these AA cells are zinc-carbon cells, which we've talked about already.

And we'll go into further detail about what zinc-carbon cells are.

You'll also notice that this battery pack has got a topper on it, which connects really easily with some wires.

So it'll be able to connect to the leads, which we'll talk about in a second.

There's a 3 to 6 volt motor, which is slightly larger.

Then the 1.

5 to 3 volt motor, they've got a 3 volt buzzer.

There's some leads, they're often called crocodile clips because of the clips that they've got on either end.

But we are gonna be defining them as leads.

There's an LED light.

And there's a bulb in a bulb holder.

Just going back to the LED light, LED stands for light-emitting diode.

Now, the components, they can all those components we talked about just earlier, they connect together so that the electricity flows through them.

And then the components work.

There you can see that we've got the leads attached to the battery pack with the two cells in, and the LED light lights up.

Now, this type of circuit is called a series circuit.

Remember when we talked about the keywords and that they go around in one continuous loop.

This is a series circuit.

Check for understanding.

What is a series circuit?

Is it, a loop of unconnected electrical components, a loop of connected electrical components, or a loop of connected mechanical components?

<v ->Which one do you think it is?

</v> That's right, well done.

It's a loop of connected electrical components.

Well done.

Now, there are different types and sizes of cells and batteries.

Now, the electrical circuit we've just looked at with that LED light lighting up that uses two AA cells.

Now, these are zinc-carbon cells.

Now, you can get alkaline or rechargeable cells.

Those are different types of cells, but we've chosen zinc-carbon, and we're going to be talking about why in a moment.

Because when we are thinking about cell and battery safety, we need to think about the dangers that are there.

So a short circuit happens when a positive and a negative terminal of a cell or a battery are connected directly to each other.

So if they're put together and they're connected together, that creates a short circuit.

And now this can be incredibly dangerous because the cells or the batteries might overheat, the components such as the leads they might melt.

There might be dangerous fumes that can come from the components.

And you could get burnt.

So we need to be very careful when we're using the cells or the batteries in an electrical circuit.

There's further dangers, we need cells and batteries are very dangerous and they might give a shock if a circuit is connected incorrectly.

So if you make a mistake and you incorrectly connect a circuit together, it can create an electrical shock.

Now, that can be quite painful, and certainly in home electrics, can be quite a really dangerous thing to do.

So it's always worthwhile making sure that you don't go near any of the electrical circuits within the home.

But within these simpler circuits, even then we need to be very, very careful that we connect everything up carefully so we don't create a spark.

We don't create a shock.

One of the biggest concerns is making sure that water is not near electrical circuits because that's very dangerous, 'cause the electricity will go through the water and can create a really serious incident.

So we need to be very careful with water around electrical circuits.

Sometimes, cells and batteries, they might be old, they might not be stored correctly, and they might have leaked.

So you have to be really careful with those 'cause those are batteries and cells you really don't want to use, and you really don't want to touch the chemicals that might be coming out of them either.

So you have to be really, really careful when we're using cells and batteries.

So how do we keep safe?

Well, there's a few key rules, and to be honest, I've sort of mentioned some of those in the previous two slides already because when we talk about the dangers, we're automatically thinking about how can we keep safe.

Now, I said I've talked to you about why we are using zinc-carbon cells, and that's because they're less likely to short-circuit.

It's not saying they won't short-circuit, but they are less likely to than alkaline or rechargeable cells and batteries.

So that's why we tend to use those or advise that we use those.

They don't get so hot, and they don't tend to short-circuit.

Now, another way of keeping safe when we're using cells and batteries, if they do look damaged, tell the teacher straight away and don't touch them.

Another way, very simple way of keeping safe is making sure that we keep water away from circuits and cells.

And a really good tip is to actually connect the battery packs last.

So connect those cells last when you are making the circuit.

And then also disconnect them first when you're finished.

It just means that you can make sure that all of the different components are connected.

And as everything's right, if you put the battery packs in last and take them out first, then that's gonna be the safest way of using the cells and the batteries.

Lastly, and most importantly, always follow the teacher's instructions carefully.

Check for understanding.

Which type of cell is best to use in school to make a series circuit?

Is it rechargeable, zinc-carbon, or alkaline?

Which do you think?

That's right, it's, b, zinc-carbon.

Zinc-carbon cells are less likely to short-circuit or get hot.

Doesn't mean they won't remember, but as long as we're being careful, but zinc-carbon cells are best to be using in the classroom.

Well done.

Right, we're going on to the task now.

So the first task I want you to complete is to discuss how to keep safe when making electrical circuits.

Then I'd like you to write down a list of instructions for keeping safe when making electrical circuits.

So the first point is discuss how you're gonna keep safe.

Have a good discussion in your small groups, or in pairs, or however your teacher decides is best for you to do this.

And then write down a list of simple instructions for keeping safe when making electrical circuits.

Lastly, we want you to actually make a simple circuit and light up a bulb.

Now, this is just a suggestion, it's entirely down to your teacher about what sort of components you use.

This is a suggestion that we might ask you to light up a light bulb with a simple circuit.

Now, of course, your teacher may choose to use a buzzer, or use a motor, or an LED, or another component, that's entirely up to your teacher's discretion for them to choose what they're going to do.

But we are suggesting simply making a simple circuit by lighting up a bulb.

Right, those are all the instructions.

You've got three different components for today's Task A.

So remember, we're gonna talk about how to keep safe.

We're gonna write a list of instructions and then make a simple circuit.

Right, looking forward to seeing how you get on with this one.

Sure, you'll have a really good time.

And remember, keep safe when you're using the electrical components, and I'll see you back for some feedback in a few minutes.

Right, well done.

Hope you've been able to keep safe.

You've got some key rules for keeping safe when using electrical circuits, and you've been successful in lighting up a light bulb or whichever component your teacher has decided.

So Andeep and his group talked about how to keep safe when making electrical circuits.

And they wrote down some ways to keep safe, so they talked about using zinc-carbon cells 'cause they're less likely to short-circuit.

And if their cells are damaged, then they'll tell the teacher straight away and they definitely won't touch them.

They're gonna make sure their water bottles are kept away from their tables.

They're gonna connect the battery packs last when completing the circuit.

And they're going to disconnect the battery packs first when they're finished.

And they're gonna make sure that they follow the teacher's instructions carefully.

Now, once they're done that, they then made a simple circuit and lit up a bulb.

Well done.

That's learning cycle one completed, and we are going on to learning cycle two now, which is switches in simple circuits.

Now, switches can be found absolutely everywhere, and they can turn lots of different things on and off.

I've just got three examples here.

So you can have lights, those are the most common ones, maybe a dishwasher, or a tablet.

There's lots of different types of switches, and they're found all over the house.

Now, switches are actually a type of input.

Now, an input to an electrical circuit is something that allows it to work or not work, or changes how it works.

Now, they change the circuit because they make it work or they create a break in the circuit to stop it working.

So their input is literally on and off.

That's how they change the circuit.

Check for understanding.

What are switches?

Are switches, a, inputs that break circuits, b, outputs that break circuits, c, inputs that break batteries, or d, outputs that break batteries?

Have a read through again, is it a, b, c, or d?

That's right, it's the first one.

They are inputs that break circuits.

Well done.

So how does a switch actually work?

So here is an example of a picture of an open switch.

The switch is off, it is open, and that creates a break in the circuit, and the bulb isn't working.

Quite simply, the switch is a closed switch on this diagram and the switch is on, so it connects the circuit and so the bulb lights up.

This is a very simple picture of how switch works, whether it is open or closed.

Open means it's off and closed means it's on.

Now, today we are gonna be thinking about how to make a switch, and it can be a very simple way of making a switch just using some simple equipment, which we'll go through in a second.

So using card, split pins and paperclips, we can actually make a simple switch.

So there's an open switch, and you can see there's two split pins and one paperclip on a piece of cardboard.

That's an open switch.

And that's a closed switch.

You can see the paperclip has moved, and so therefore it's connected the circuit together.

Now, wires from the circuit are connected below the card to the split pins.

You can't see that there.

There will be other pictures, the moment, which will make it a bit clearer.

But you can see that, just imagine there's gonna be some wires clipped onto the split pins underneath the cardboard and that's what helps connect it to the circuit.

What will we need today to make a switch?

Well, let's go through all of the different resources that you're going to need.

You're gonna need scissors, pencil, sticky tack, split pins, just two.

Some card can just be a piece of scrap card.

You don't need to make anything in particular for it, but just a piece of scrap card that's lying around.

A paperclip, and some circuit components.

And there, in those components, we've got some crocodile clips.

We've got a battery pack with two zinc-carbon cells in it and a bulb in a bulb holder.

Here's the stages of making the simple switch.

We'll go through one at a time.

So the first thing to do is to mark where the split pins will go and then safely make the holes.

We'll use the sticky tack underneath and then poke the pencil through to make a nice, safe hole.

Now, you can see that we've used the paperclip there to mark where the holes are gonna go 'cause the paperclip is going to be the size of the switch.

We're then going to attach the paperclip and the split pins to the card.

And then you can see you keep one of the paperclips in place and then you poke the one of the split pins through and then you put the other split pins through.

Not forgetting, we're gonna be talking about the underside in a second.

So we've fold out the split pins so that they don't touch.

And you can see that those split pins there don't actually touch.

So that's the right way of doing it.

Well, we don't want to do, and this is really important, is actually having the split pins touch.

Because if the split pins touch, then that creates the circuit that connects the circuit.

And so it doesn't matter what you do with a paperclip on the top, the circuit's still going to work.

Lastly, you're going to attach the circuit to the split pins and test the switch.

And there you can see the crocodile clips are connected to the split pins, as I spoke about in the previous slide.

And then we've connected it up to the circuit.

Remember, we'll put the battery pack, we'll attach that last.

So there we go.

We've got a light bulb lighting up when the switch has been pushed over.

Right, good.

Hope that all makes sense.

Check for understanding now.

Which of these will not be used to make a simple switch?

Is it a, a glue stick, b, paperclips, or c, split pins?

Which of these will not be used to make a simple switch?

Which one do you think is the correct answer, a, b, or c?

That's right.

Well done.

It's a glue stick.

We don't need a glue stick today, but we are gonna use paperclips and we're gonna use split pins.

Well done.

So here we go with Task B.

Now, there's two parts to this.

I'm gonna go through the first part.

Make a simple switch using card, paperclips, and split pins.

So there we go.

We're gonna be making the holes, we're going to be adding the paperclip and the split pins.

We are gonna check on the underside and make sure it's accurate.

So that's your first thing is to make a simple switch using card, paperclips, and split pins.

Secondly, we are going to connect the simple switch to a simple series circuit and then test to make sure that it works.

So don't do the simple series circuit until you've completed the switch first, right?

Remember, we're still going to be having those safety rules from Task A.

So follow those, make sure you're being safe and I look forward to seeing how well you've got on with this.

Hopefully, you've been able to do this really, really well, and I look forward to speaking to you when we come back in a few minutes to talk about the feedback, right?

Off you go, enjoy.

Keep safe.

And I'll see you in a few minutes.

Here's Aisha.

Aisha made a slide switch and connected it to her simple series circuit to test it.

And she found out that the bulb lit up when the switch was on, and it went off when the switch created a break in the circuit.

And there you go.

There's a short GIF showing you how Aisha created all of these things, and you can see the light bulb turning on and turning off.

Well done, Aisha, and well done, you.

I'm sure you've been able to do something similar too.

Right, let's go through the summary of today's lesson's components in a simple circuit.

So a loop of connected electrical components that goes from one side of a cell or battery to the other is called a series circuit.

Zinc-carbon cells and batteries are safer to use in schools as they are less likely to short-circuit.

When making a series circuit, connect the battery pack last.

Disconnect it first when taking the circuit apart.

Switches are inputs in the electrical circuits.

And lastly, simple switches can be made with split pins, card and paperclips.

That's the lesson finished, you've done brilliantly today.

Well done.

We've come up with so many high-quality rules for keeping safe with electrical circuits.

You've made your own electrical circuit and you've made and included a switch as well.

You've worked really hard.

Well done today.

I look forward to working with you next time.