Hello scientists, my name is Mr. Wilshire and in this lesson we are going to be looking at investigating voltage.

This is the planning stage.

The outcome for our lesson is to plan to investigate how voltage affects the brightness of a bulb in a circuit.

There are some key words for our lesson, so let's go through some of them now.

The first one is cell.

The next, battery.

Now, voltage.

Then we have affect and brightness.

Now don't worry if you're not too sure what some of these keywords mean, the definitions are coming up on the screen now, so if you'd like to, you can pause video here and have a quick read to remind you.

Then you can continue when you are ready.

The first part of our investigating voltage planning lesson is called voltage.

Now, Sophia has noticed that cells and batteries come in all sorts of different shapes and sizes.

She says there are many types of cell.

Here are a range of devices with different cells.

There's a doorbell ringer there, so you can put it anywhere.

There's a doorbell button, the garage door opener as well, if you have an electronic one of those, and a TV remote control.

There are many types of cell.

You can see there, the doorbell ringer is, well, they're quite large, but long batteries.

The doorbell button is a smaller version of those.

The garage door opener is a circular battery and the TV remote control is a thinner version of the batteries found in the doorbell ringer.

I wonder if you've seen any of these types of cell or battery before or whether you've had to change some of these things so that your device will work.

Here's Sophia again and she says cells and batteries provide the push to make electricity flow around a circuit.

Here is a cell and when we have one of these units, we call it a cell.

But when there are two or more cells working together, we call it a battery.

Here is a battery of two cells, for example.

Now the voltage of a cell is a measure of the size of the push that it provides.

Here is a cell and on there you can see it's showing the voltage as well.

Take a moment to study that picture quickly.

Where can you see the voltage? Restart the video when you've done that.

Did you spot it? It's just over here, look, the voltage or push, is measured in a unit called volts.

In this case, it's 1.

5 volts.

So a high number of volts would mean a much stronger push.

The V on a cell or battery stands for volts.

Alessandro Volta is considered by many to be the first to make a cell or battery.

You can see here an Italian bank note showing a picture of Volta there.

He was an Italian scientist and he lived from 1745 till 1827.

Well, hang on, I didn't think that cells and batteries have been around for that long, let's find out some more.

So the words voltage and volts come from his surname.

The Italians are very proud of Volta, so they placed his image on one of their bank notes.

So Volta discovered a way to make electricity flow.

So he made a pile of discs of two different types of metals.

He separated all of these by little pieces of cloth soaked in liquid.

You can see metal one, metal two, and then other cloth soaked liquids there as well.

So the silver is showing off metal one, the gold is showing off metal two.

So when you completed the loop with the metal wire, the metal discs and liquid began to react with each other.

So that meant that he could see a flow of electricity was produced.

You can see the metal wire there and then the flow of electricity, he's created a circuit, hasn't he? It is this flow that provides the push to our electrical circuits.

So is this what's happening inside a battery or cell? So like Volta's invention, modern day cells contain two different metals and a liquid or a type of paste which reacts together to produce electricity when everything in the circuit is connected together correctly.

You may have seen some of this liquid or paste leaking out because when a battery gets old, sometimes it can go a little bit funny and that paste can leak out.

It does take a very long time for this to happen though.

So different combinations of metals and liquids create batteries with different voltages.

So you can see here there's a modern cell and it is three volts.

So stop and think, what is the name of this component? Read the statements there, have a discussion and restart when you've done that.

This component is called a cell.

So what does the V on the cell stand for? Read the statements, have a discussion, and restart when you've done it.

The V on the cell stands for volts, did you get that right? Try one more.

Blank is a measure of the push a cell provides to a circuit.

Voltage is a measure of the electrical push a cell provides to a circuit.

Let's look at the first task in our lesson.

Look at a range of cells and batteries with their voltage covered.

If you don't have any, you can use the images provided on the next slide.

You need to measure the length of each one, predict the voltage of each one, and then reveal the voltage of each cell or battery, recording your findings in a table, a little bit like the one you can see here.

So the example here that's been done shows that the length of the cell is four centimetres.

Now they predicted the voltage would be 1.

5 voltage.

The actual voltage was 1.

5, so their prediction was correct.

Well done, then.

If you don't have any of your own cells, you can use the images on the next slide.

So if you don't have some of your own, here are some cells to get you started.

We've covered up the voltages, so you'll have to predict what they are.

Use these images to help if you need them and restart the video when you are ready.

So here are some answers for the previous pictures.

Now, I didn't predict all the voltages correctly here, I thought that the bigger the size of the cell, the higher the voltage would be, but that wasn't always true, but that wasn't always true.

A and B, for example, are two very different sizes of cell, one is two centimetres and the other is five centimetres.

The voltage on the cell, though, remains the same.

So I wonder if your predictions were accurate here, what did you discover? The next part of our lesson is called increasing voltage.

Now, Sophia found that her cells range from 1.

2 volts all the way up to nine volts.

Here you can see an example of a nine volt cell.

She says, I wonder if nine volts is the highest voltage that exists.

Oh, maybe Sophia.

Other sources of electricity have higher voltages than Sophia's cells though.

I wonder if you can think of any.

Do you know of any sources of power that have a higher voltage than this? Talk to your partner and discuss.

Restart when you've done that.

So petrol and diesel cars have got batteries in them as well, this helps us start the motor.

You can see here an example of a car battery.

What do you think the voltage of a car battery is? Use your previous discussion to help you here.

Did any of you think that a car battery would have more than nine volts? Restart the video when you've done that.

There are lots of different types of batteries, aren't there? Cars are one such example of a device that needs a higher power source.

What about your phones or devices though? I wonder what kind of batteries they have in them.

Are they stronger than nine volts? The batteries that you get inside a device like a tablet or a phone would be a little bit different to the ones that we've been looking at so far.

I wonder what voltage they do actually have.

Car batteries though, are 12 volts, that's a lot higher than nine, isn't it? The main's power in our homes is 230 volts.

Well, you can see why it's very important not to play around with plug sockets.

230 volts is a very high voltage and that could kill a person, so we should never play with electrical sockets or appliances at home.

Lightning is a natural source of electricity.

What do you think the voltage of lightning is? Is it going to be the same as the type of power that we get in our homes or is it gonna be more or maybe less? You discuss now and restart when you've done that.

A typical lightning bolt is usually 1 billion volts.

Oh my goodness, that is an incredible amount of power, isn't it? No wonder you hear of people being seriously injured by lightning, but it is very rare for it to strike anybody.

So Sophia wonders if the voltage of the cell or battery affects how a circuit works, what do you think? Pause the video and have a discussion.

Restart when you've done that.

I hope you've been able to have a good discussion about how a circuit works.

Jun here says I might try some different voltage cells and batteries in my circuit to light a bulb and then observe what happens.

Hmm, that's a good idea, isn't it? Sophia would like to investigate Jun's idea, but she's a bit worried.

Why do you think she's worried? Let's find out.

She says we only have one type of cell, so I can't investigate different voltages.

Hmm, you're going to need different types, aren't you? To investigate this.

What could Sophia do? Pause the video here, have a discussion, and restart when you've done that, I wonder what Sophia's going to do here, let's see if she uses any of your ideas.

Now you can change the voltage in a circuit by using a different number of cells.

One AA cell provides a push of 1.

5 volts.

How much push do you think two AA cells could provide? Have a think, restart when you've done that.

Let's see if you were correct.

A battery made from two AA cells provides a push of three volts.

Oh yeah, it's 1.

5 and 1.

5, isn't it? Here you can see an example, two AA cells forming a battery.

The greater the number of cells, the higher the voltage.

So some bigger cells that we use at home are really batteries.

Now this is because they're made up of lots of different cells working together.

Remember, a battery is the name that we use when two or more cells need to work together.

This image here shows the inside of a nine volt battery and it contains six different 1.

5 volt cells.

Wow, so inside these batteries, it's just a cluster of different types of cell.

Oh, I never knew that.

So a nine volt battery that you can see here, is just made up of lots of AAs.

You should never open a cell or battery though because the liquid and metal inside are very dangerous and they can make you unwell.

Let's stop and think here.

What does adding more cells do to the voltage of a circuit? Read the statements, have a discussion, restart when you've done that.

The answer is it creates a higher voltage.

The more cells, the higher the voltage.

Here's another one, cells or batteries with a higher voltage discuss.

Restart when you've done that.

The answer here, this creates a stronger electrical push to a circuit.

So here's the next task.

The children are discussing how they could change the voltage on their simple circuits.

Sophia says, to change a voltage in a circuit, we need different voltage cells and batteries.

Ah, I wonder if here she's going to use any of your ideas.

Jun says, to change the voltage in a circuit, we need different numbers of cells.

Who do you agree with and why? Good luck with this task, restart the video when you've done that.

Now your discussions could have looked something like this.

Now, both children are correct, you can change a voltage in a circuit either by using cells or different voltage or by changing the number of cells that you use.

So to change the voltage in a circuit, we need different voltage cells and batteries.

And to change the voltage in a circuit, we need different numbers of cells.

The next part of our lesson is called investigating voltage.

Scientists and engineers are interested in how voltage affects electrical circuits.

Here's a scientist and they say, to affect something is to change what it does or how it behaves.

It's really important that electricity is safely transported at the right voltage to our homes and within our appliances.

So studying voltage can also help scientists and engineers work together to design better cells and batteries that last longer or are easier to carry.

Understanding voltage is very important in medical science.

It is important that people are not injured by medical equipment.

You can see there a defibrillator trying to get someone's heart working again.

Now, this is only a model to show you what it looks like, but these devices are really used to try and jumpstart your heart into pumping blood again.

It would be very dangerous if it gave out the wrong type of voltage, wouldn't it? So scientists need to plan different types of inquiries to find answers to questions.

Sophia, for example, wants to know how voltage affects how her circuit works.

She says, I wonder if the bulb in my circuit gets brighter when I increase the voltage of the cell.

I wonder what you think here.

Let's move on and find out.

Her friends have come up with some questions.

Sam says, does higher voltage make the electricity flow faster? Jun says, which is the best voltage for my circuit? Izzy says, does the voltage affect the brightness of the bulb? Hmm.

Which of these should Sophia choose for her inquiry question? They're all good ideas, aren't they? But which one is the best? Pause the video and have a discussion.

Restart when you've done that.

The best question for this inquiry though, is Izzy's, does the voltage affect the brightness of the bulb? Let's stop and think.

Scientists plan different types of blank to find answers to questions.

Read the statements, discuss, restart when you've done that.

The correct answer here is inquiries.

Scientists plan different types of inquiries to find their answers.

Which of these questions could be answered with a scientific inquiry? Read the statements and discuss, restart when you've done that.

These two questions here could help, which buzzer is the loudest and which motor is the fastest? So the children begin to plan their inquiry to find the answers to their question, does the voltage affect the brightness of the bulb? They think about the variables in their investigation.

Izzy says, remember to only change one variable so we can see the effect that it has on the results.

Which variable do you think that they should change here? Discuss and restart when you've done that.

I wonder which variables you thought of.

Let's have a little look, shall we? Now, Sophia will change the voltage of cells and batteries.

Look, there's an example of the thing that you should change there, does the voltage affect? So we're going to change the voltage here, that's the only variable.

She will control all of the variables by keeping them the same.

So what is Sophia going to observe or measure here? Have a think, restart when you've done that, Sophia is going to measure the brightness of the bulb.

So how could she do this? Pause the video and discuss.

I wonder what you said.

Well, she says, I will observe how brightly the bulb shines each time using my eyes.

I wonder if there's any scientific equipment that we can use to measure light? Sophia though is going to use her eyes.

Pause and think, which do you need to do when planning an inquiry? The answer here is identify and control variables, only one thing is allowed to change.

So here is your final task, you need to plan an investigation to answer Sophia's question, does the voltage affect the brightness of the bulb? Discuss and record.

What equipment will you need? What are you going to do? Which variables will you change? Which variables are you going to need to control? And what will you measure and how are you going to measure it? If you're choosing to measure using your eyes in this case, be very careful not to stare at it for too long.

And I wonder if there's any scientific equipment that you can research that's going to help you to actually find out how bright something is.

That could be an extra task for you to try, couldn't it? Good luck with your task, restart the video when you've done it.

Well, I hope you enjoyed doing that investigation.

What did you find out? Your plan may be similar or maybe different to this.

We will need some wires, a range of cells, and a bulb in a holder, and this is what we will do.

We're going to build a circuit with two wires, a cell and a bulb, measure the brightness with our eyes and decide if it is very bright or dim.

We will change a cell and then repeat, That we're going to change is the cell and we'll keep the wires and the bulb the same each time, yeah, that's very important, they need to keep the bulb the same every time.

There's no good getting a different type of bulb it might give out a different type of light.

So hopefully you get a chance to actually run this experiment as well.

And maybe, as I said before, research the type of equipment you could use to measure how bright something is.

So let's summarise our lesson.

A cell is a single unit that's needed for electricity to flow around a circuit and a battery is a group of these cells.

The V on a cell or battery stands for volts and is a measure of the size of the electrical push it provides to a circuit.

Adding more cells creates a higher voltage and a stronger electrical push to a circuit.

Scientists plan different types of inquiries to find answers to questions.

Well, hopefully you've been inspired to find some answers to your own questions today.

Or maybe you're going to explore electricity a little bit more.

Maybe you need to find out the different type of bulb that you might need to use and the type of voltage that you can use to make it brighter or dim.

That could help if you're trying to create a nice light to help you to go to sleep, as you don't want it to be very bright then, do you? Best of luck for all you're investigating in the future.

My name has been Mr. Wilshire, thank you very much for listening.