Lesson video

Hi, I'm Mrs. Hudson, and today I'm going to be teaching you a lesson called Making a Series Circuit.

This is a key stationary science lesson and it comes under the unit titled series circuits.

So let's get going.

The outcome of today's lesson is I can use a circuit diagram to build a series circuit and draw a circuit diagram of a completed circuit.

Now during today's lesson, there's going to be a few keywords that are going to be used frequently throughout the lesson, and those keywords are series circuit, circuit diagram, circuit symbol, and complete circuit.

So let's look at what those mean.

A series circuit is an electrical circuit with one complete loop from one end of the battery to the other end.

A circuit diagram is a simple and clear way of showing the setup of the components in an electrical circuit.

Circuit symbols are used to show electrical components in a circuit.

They are simple to draw and easy to recognize.

And a complete circuit is one where there are no gaps, so electricity is able to flow round the circuit.

If you want to pause the video to make a note of those keywords, then please do and then press play, ready to continue.

Today's lesson is going to be split up into three parts.

In the first part of the lesson, we're going to be looking at what is a series circuit.

Then we're going to move on to look at building a series circuit.

And then finally, we're going to finish off the lesson by drawing a series circuit, but let's get going with the first part of the lesson, what is a series circuit? So this image here is showing you a series circuit.

This series circuit contains three electrical components and some leads.

So we can see that we've got one cell which is used when we draw circuit diagrams, using that symbol there, but in the picture is what is being pointed to by the purple line.

Then we've got the leads which are connecting the components together and they're represented by straight lines in our diagrams. We've got a switch which is represented by those two symbols there, the top symbol is showing you an open switch and the bottom symbol is showing you a close switch.

And then finally that is a lamp, which is a bulb which can light up, but when we draw circuit diagrams, we label them as lamps with the following symbol.

Circuit symbols are used to draw a circuit diagram, so this is an example of a circuit diagram which has got circuit symbols within it, and we can see that we've got this symbol here, which is showing you a cell.

The cell has got a positive and a negative terminal, and when we draw that, the positive terminal is a slightly longer thinner line, and the negative terminal is a shorter and wider line.

We represent the leads as straight lines connected together, and it's very important that they are connected together and touch.

Then a switch is drawn with this symbol here, and we can see that there's an open switch at the top and then a closed switch at the bottom.

And then finally we would draw a lamp in a circuit diagram like this, which is a circle with a cross within it.

Now it's really important to note that the wire lines do not go through the circuit symbols.

Let's quickly check our understanding so far.

Which of these is the correct symbol for a lamp? A, B, or C? This is B, well done if you've got that right, and have a think now, why is A wrong? A is wrong because although they've drawn a circle with a cross inside of it, the wire line is going through the symbol for a lamp and that is wrong.

And C is wrong because a lamp has a symbol with a circle and then a cross inside, and that is not correct.

So well done if you recognize that it was B.

There are other components used in electrical circuits.

So so far we have spoken about the cell, the wires, a switch and a lamp, but here are some other components.

There's a motor.

That's what a motor looks like on the bottom if you are setting up a circuit.

But when we're drawing a circuit diagram, it's a circle with a capital M inside of it.

There's a resistor.

The resistor looks like the bottom picture when you are using circuits in the classroom, but when we draw it, it looks like that.

So it's a rectangle.

A volt meter which measures voltage is a circle with a V inside, but would look like that in the classroom.

And an ammeter looks very similar to a volt meter, but the circuit diagram representation is a circle with an A inside of it.

Let's check our understanding.

Which component is represented by the symbol below? A, a motor? B, a volt meter? Or C, a multimeter.

This is A, a motor, well done if you got that right.

A cell has a positive and a negative terminal, which we've spoken about before.

And when we draw our circuit component, the thin longer line is a positive terminal and the shorter wider line is the negative terminal.

Ammeters and voltmeters also have positive and negative terminals, which we can see in these images here, but we don't have to draw those on the circuit component diagrams. Components need to be connected the correct way round in a circuit and you will find out how in the circuits that you make.

Circuit diagrams are used to give a clear simple representation of a circuit.

So if we had this circuit here which contains two cells, a lamp and a switch, the circuit diagram would look like this.

So we've got the two cells and it's really important to make sure that when we're connecting cells together that the positive end of the terminal stays the same orientation.

So one cell has the positive to negative terminal and then the new cell is connected with the positive terminal starting first.

And then we can see that we've got the switch and we've got the lamp.

Now really importantly, it doesn't matter if the components are moved around the circuit as long as they still are in the same order.

So to highlight again, there are two cells in the circuit diagram.

Two cells together make a battery, so a battery contains more than one cell.

Then you've got the lamp, in the circuit diagram on the left hand side it looks like that.

But when we are drawing our circuit diagram, we draw a circle with a cross inside of it.

And then finally there's the switch.

And in the circuit diagram that is represented as the close switch symbol there.

Let's check our understanding of that.

Which of the diagrams correctly show the circuits below? A, only circuit diagram one, B, only circuit diagram two, C circuit diagram one and three, and D circuit diagrams one, two, and three.

Now the answer to this question is D, it's circuit diagrams one, two, and three.

And the reason the answer is D here is because you can move the components around within the circuit as long as they stay in the same order.

Now, this is quite a tricky question because you have to look at the positive and the negative terminal of the cell to look at which components should come next.

So if you look at the diagram at the top, the positive terminal, if you go left outta the positive side of the cell, the bulb comes first and then the switch.

Whereas if you look at diagram four, you'll notice the positive terminal is on the right hand side and if you go right outta the positive terminal, the switch comes first and then the lamp, and that is the wrong way round.

So well done if you manage to spot that.

This is a series circuit.

It is a complete circuit.

There is only one complete loop and there are no junctions.

You've got two cells, a lamp and a switch, and every single one of those components is connected together.

What that means is electricity can flow around the whole circuit because everything is connected together.

In a series circuit, electricity passes through all of the components, one after the other, and then continues to go round in a loop.

So electricity will always be flowing around in the same direction and continuously moving around that complete circuit.

A circuit must be complete to allow electricity to flow.

If there is an open switch, electricity will not flow.

The circuit needs to be completed by closing the switch.

If you press down on the switch in the circuit diagram, that will connect the metal pieces together and that will complete the circuit.

When you lift your finger off the switch, then the metal pieces will no longer be touching anymore and electricity cannot flow, and that would be an open switch.

Let's check our understanding.

Which of the following shows a completed series circuit? A, B, or C? This is A.

A is the only one where the two cells are connected together and the two bulbs are connected together.

In B, the two cells are not connected to each other and in C, again, the two cells are not connected to each other.

Well done if you manage to get that right.

We're ready now to move on to the first task of our lesson.

So in the first part of task A, you need to list the components A to D shown in the circuit below.

And then number two is this circuit diagram correct for the circuit shown and you need to explain your answer.

I'm sure you're going to do a really great job.

Pause the video and then press play when you're ready for me to go through the answers.

Let's see how we did them.

So the components A to D, were A, a battery, B, an ammeter, C, a lamp and D, a motor.

So well done if you've got those right.

And then for number two, that circuit diagram was correct.

The components are connected in the correct order and there are no gaps in the circuit.

Do note though, it does not matter if the components are not in the same position so they can move around as they are in the image as long as they remain in the same order.

So really great job if you manage to get that right.

If you need to pause the video to correct your work or add in anything you might have missed, then please do.

But we're going to move on now with the rest of the lesson.

Well done.

So far we know what a series circuit is, and now we're going to look at building a circuit.

To build this circuit, you would need three cells, one switch, one ammeter, one lamp, one motor, and five leads.

We know that because we can look at the circuit diagram and look at the component symbols to work out which components we need.

So to start with, we would have a battery here that contains four cells.

Now remember that our circuit diagram only had three cells within it.

So we're going to start by picking any point in the circuit and then add each of the components in the same order as they appear in the circuit diagram.

So we're going to use a switch first and we're going to add that into our circuit by connecting the switch to the battery using a wire.

Then we will use another wire on the other side of the switch to connect the switch to the ammeter and make sure that the wire is plugged into the positive to terminal of the ammeter.

We would then add another wire to the negative terminal of the amateur and connect that up to the lamp.

And then finally, we would use another wire to connect the lamp to the motor, and then we would use another wire to connect the motor to the third cell of the battery.

Now remember, the reason why we're using only the third cell is because the diagram we saw at the beginning only had three cells.

Now, to make sure that the circuit is connected, you will have to push down on the switch to make sure that the metal components touch together, and this allows electricity to flow all around the circuit and the circuit is now complete.

When building a circuit, it is possible to start with any component as long as the rest of them are added in the correct order.

The components can be in different positions, which we can see in these two diagrams here, we've got three cells, and if we go to the positive terminal on the left hand side of the first cell and then go to the left, we've got a motor, then a lamp, then an ammeter, then a switch.

Now if we look at the circuit on the right hand side and go to the first cell on the left at the positive terminal, it's again motor, lamp, ammeter, switch.

They're just in different positions.

These circuits are the same even though the diagrams are drawn differently.

But remember, it is the order of the components that is important.

So if the components remain in the same order that are in different positions, that's okay.

Let's check our understanding.

When building a circuit from a diagram, what is the method used? A, start at any point and connect each component in order ensuring none are missed? B, always start at the battery and finish there.

Or C, the finished circuit should look exactly like the diagram.

The answer to this is A, well done if you got that right.

Remember we said you could start at any point, but you must connect each component in order ensuring that none of them are missed.

So well done if you recognize that.

We're ready now to move on to task B of the lesson.

So you need to list the steps you should take to build the circuit shown.

Now a hint for this, you need to explain how you would start to make this circuit in the classroom and make sure you list all the components that you would need.

I'm sure you're gonna do a fantastic job.

Press pause and then play when you are ready for me to go through the answers.

Let's see how we did.

So the first thing you would need to do is count the number of components and wires that are in the circuit diagram.

And in this case, you would need to collect two cells, three lamps, one switch, and five wires.

So well done if you wrote those down.

Then you would arrange the components in the same order that they are shown in the diagram.

So if you haven't said that, they need to be in the same order, that's really important.

And then starting with any component, connect it to the next component with a wire, the battery's often a good place to start, but it doesn't have to be the battery.

And then finally, repeat step three with each component in turn, checking that the circuit matches the diagram.

You might have also written in there that there should be no gaps and that each component needs to be connected to the next component with a wire so that you create one single loop.

Really fantastic if you've managed to get all of that into your answer.

If you need to pause a video to add anything in, please do, but we're going to move on now with the final parts of today's lesson.

You've done a really fantastic job so far.

So we know what a series circuit is.

We know how to build a series circuit, so let's have a go now at drawing a circuit.

Circuit diagrams are drawn so that they are clear and easy to understand.

They are drawn using a set of simple rules.

Components are represented by circuit symbols, which we've spoken about previously in the lesson.

Straight, horizontal or vertical lines are used for wires, and we should be using a ruler to draw those.

The wires are drawn between the components with no gaps at all, so every single line needs to be connected.

The battery or power supply is usually at the top or the left, but you can start drawing the circuit at any point.

When drawing a circuit diagram, you need to use a sharp pencil, a rubber, and a ruler.

We use a ruler to draw vertical and horizontal lines and make sure they're straight, and a pencil and a rubber so that if we make a mistake, we can rub it out easily.

Let's have a look then how we draw a correct circuit diagram.

So we've got a diagram here which has got two cells, a lamp, and a switch.

So how would we draw that? First of all, we would start with the battery, which contains two cells, and we would do that by drawing the positive terminal first, which is a long thin line.

Then the negative terminal and the negative terminal is connected by a single horizontal line across to the next positive terminal of the next cell.

Notice that in between the two lines for the cell, there isn't a horizontal line going across.

Then we need to make sure that we've got the two wires going straight down.

Now let's have a look at the lamp.

So to draw the lamp, we draw a straight line down and then a horizontal line across.

We draw the circle with the cross inside of it.

Now note here that the wire line does not go through the symbol for a lamp.

And now finally, to draw the switch on, we draw two little circles and to show that the switch is closed, we draw a line which is touching both of the circles.

Now notice that in the circuit diagram there are no gaps.

The only gaps that you should ever see are between the positive and the negative terminal of the cell.

Otherwise everything else is connected.

But we do not draw a line through the component symbol of a lamp.

The correct circuit symbols are used, but they don't have to be perfect.

So those are the correct symbols, but sometimes when you are drawing them, they might not be 100% perfect, and that's okay.

Straight horizontal or vertical lines are drawn between the components with no gaps at all.

This circuit diagram here is acceptable.

We can see that there are straight horizontal and vertical lines that all the lines are touching.

There's no wire line going through the lamp component.

And we can also see that the positive and negative terminals of the cells do not have a line through them either.

These symbols are not perfectly drawn, but the components they represent are clear and they are in the correct order.

Let's check our understanding.

Which of the circuit diagrams below is drawn correctly? This is C.

Well done if you managed to get that right.

The reason why A is wrong is because the wire lines are going through the lamp and the ammeter components.

B is wrong because if you look at the cells at the top of the diagram, the cell on the right hand side, the wire is not going into the negative terminal of that cell so it's not a complete circuit.

Whereas C is showing a complete circuit and it's very neat.

So well done if you recognize that.

We're ready now to start the final task of the lesson task C.

And in the first part of task C, you need to label the errors in the circuit diagram below.

And then in the second part, you need to draw a correct version of the diagram.

I'm sure you're gonna do a really fabulous job.

Pause the video, give it your best go, and then press play when you're ready for me to give you the answers.

Let's see how we did.

So there were a few errors on this circuit diagram.

So if we start with the switch, you can see that they've drawn a line through the switch, which is incorrect.

It was trying to show an open switch, but it was difficult to tell if it was an open or a close switch because they've drawn the wire through the two circles.

They've also drawn one lamp that's lovely, but then the other lamp has the incorrect symbol for the lamp, the cross isn't held within the circle and it looks very messy.

And then finally, the problem with the wires around the motor is that the lines have been drawn curved, and not with a ruler, and they're not straight.

Now number two, hopefully you have managed to draw a correct version of the diagram that looks like this.

So all the lines should be straight and drawn with a ruler.

We can see that there are three cells that form the battery at the top.

Then you've got the open switch without the line going through.

And two lamps drawn with nice, neat symbols and a motor.

Make sure that all of your wires are touching the components and the only gaps that we should see are between the positive and the negative terminal of each individual cell, and also that the switch is open.

Fantastic job, well done.

If you need to pause the video to correct your answers, please do.

But we're going to summarize what we've learned so far in the lesson.

Well done on today's lesson about making a series circuit.

You've done a fabulous job.

Let's have a look at what we've been learning.

Circuits are represented by circuit diagrams, which use symbols for components, and we looked at the different symbols for cells, lamps, switches, motors, ammeters, and voltmeters.

Simple rules for drawing circuit diagrams help ensure clarity.

A series circuit has one complete loop from one end of the battery to the other.

And when building circuits follow these rules, which helps prevent mistakes.

And we said always use a ruler, a pencil, and a rubber, because if then you do make a mistake, you can just rub it out.

Really great job of today's lesson.

I've enjoyed teaching it to you.

I hope you've enjoyed it too, and I look forward to seeing you next time.