Lesson video

Hello, everyone.

How are you today? I hope you're feeling really good.

My name is Ms. Afzal, and I'll be your teacher for this lesson.

I'm feeling really good about that because today, we're looking at electricity.

I think that's such an interesting topic.

Our lesson is called Investigating voltage: plan, and it comes from the unit of work Changing circuits.

I wonder how much you know already about electricity and voltage.

And don't worry whether you've got much experience or not; we are gonna be getting right into this topic today.

So if you're ready with some focus, energy, and enthusiasm, we'll begin our lesson now.

The outcome for today's lesson is: I can plan to investigate how voltage affects the brightness of a bulb in a circuit.

I hope that sounds of interest to you.

We have some keywords in our lesson.

I'd like us to go through them one at a time.

My turn, your turn.

Are you ready? Cell.

Battery.

Voltage Affect.

Brightness.

Good to hear those words loud and clear.

Do you know the meanings of any of these words? Pause here and share with someone if you do.

Thanks for sharing what you know.

Let's find out more about these meanings.

A cell is a single unit that is needed for electricity to flow around a circuit.

A battery is two or more cells working together.

Voltage is a measure of the size of the push provided by a cell or other source of electricity.

To affect something or someone is to change it or how it behaves.

And the brightness of a bulb is the amount of light it gives out.

So these are our keywords: cell, battery, voltage, affect, and brightness.

Let's look out for them, let's listen out for them, and think carefully about them.

They'll be coming up in today's lesson.

Our lesson today is called Investigating voltage: plan, and it has three learning cycles.

First of all, voltage, next, increasing voltage, and then investigating voltage.

Let's begin with voltage.

Sofia has noticed that cells and batteries come in different shapes and sizes.

There are many types of cell.

And here are a range of devices with different cells.

We can see a doorbell ringer, a doorbell button, a garage door opener, and a TV remote control.

Pause here and share with someone a device that you have in your home or at school, which contains cells or batteries.

Thanks for sharing.

Cells and batteries provide the push to make electricity flow around a circuit.

So here's a cell.

When we have one of these units, we call it a cell.

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

So this is a battery of two cells.

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

Voltage is measured in a unit called volts.

A higher voltage means a stronger push.

The V on a cell or battery stands for volts.

And here is a cell showing the voltage.

Pause here and share with someone what is the voltage of this cell.

Thanks for sharing.

This cell has a voltage of 1.

5 volts.

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

He was an Italian scientist who lived from 1745 to 1827.

The words voltage and volts come from his surname, Volta.

The Italians are so proud of Volta that they built a statue of him.

And look at this magnificent statue of Alessandro Volta.

Volta discovered a way to make electricity flow.

He created a stack of discs made from two different types of metal, separated by pieces of cloth soaked in liquid.

When he completed the circuit with a metal wire, the metal discs and liquid began to react with each other, producing a flow of electricity.

This flow provides the push to our electrical circuits.

So if we take a look at this diagram, we can see we have: there's two metals, metal 1 and metal 2, and then in between each of them, we've got the cloth soaked in liquid.

And then Volta attached this metal wire to complete the circuit and produce a flow of electricity.

Like Volta's invention, modern-day cells and batteries contain two different metals and a liquid or paste that react together to produce electricity when the circuit is correctly connected.

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

Let's have a check for understanding.

What is the name of the component shown below? Is it A, a power pack, B, a battery, C, a cell, or D, an electricity pack? Pause here while you decide what is the name of this component shown on the screen.

Well done if you selected answer C.

Indeed, this component is a cell.

Let's have another check for understanding.

Choose one box on each row to form a correct explanation about batteries.

So choose from either A or B.

Voltage is something that flows around a circuit, or voltage is the measure of the strength of a battery's push.

Pause here while you choose one of these.

Next, choose from one of these explanations, C, D, or E.

The V on A battery stands for Venn.

The V on a battery stands for volts.

The V on a battery stands for value.

Pause here while you choose one of these.

And onto the final explanation.

Choose from one of these two.

A large battery has a higher voltage than the small one.

A large battery can have the same voltage as a small one.

Pause here and choose one of these.

Well done for making your selections.

On the first line, did you choose explanation B, voltage is the measure of the strength of a battery's push? Well done if so.

In the second row, did you choose explanation D, the V on a battery stands for volts? Well done.

And in the final row, did you choose explanation G, a large battery can have the same voltage as a small one? Well done if you chose these explanations.

And now it's time for your first task.

I'd like you to look at a range of cells and batteries with their voltages covered.

If you do not have any, use the images provided on the next slide.

First of all, measure the length of each one.

Number two, predict the voltage of each one.

And in three, reveal the voltage of each cell or battery.

Record your findings in a table.

So your table could look like this.

First of all, the length of the cell or battery in centimeters.

Next, you predict the voltage in volts and then write down the actual voltage in volts.

So pause here while you have a go at this task.

I'll see you when you're finished.

It's good to be back with you.

So, how did you get on with that task of predicting, finding, and recording the voltage of a range of cells and batteries? Let's hear a response.

"I didn't predict all of the voltages correctly.

I thought that the longer the cell, the greater the voltage would be, but that wasn't always true." So let's take a look.

So we've got A was two centimeters long, predicted voltage, 0.

5, actual voltage, 3.

The next one was five centimeters long, predicted voltage, one volt, actual voltage, nine volts.

And then we had length of battery, seven, predicted voltage, 1.

2, actual voltage, 1.

5.

So even though this was longer than a five-centimeter-long cell or battery, the voltage was lower and so on.

And were your predictions accurate? Pause here and share with somebody how accurate were your predictions.

Thanks for sharing, and well done for having a go at this task.

And now we're onto our next learning cycle, increasing voltage.

Sofia found that her cells and batteries ranged from 1.

2 volts to 9 volts.

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

Other sources of electricity can have higher voltages.

Can you think of any? Pause here and share with someone.

Anything higher than this nine-volt battery? Thanks for sharing.

Petrol and diesel cars have batteries to start the motor.

What do you think the voltage of a car battery is? Pause here and share with someone.

Thanks for sharing your ideas.

Car batteries are 12 volts.

The mains electricity in our homes is 230 volts.

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

Lightning is a natural source of electricity.

Oh my, take a look at that lightning in this image.

So stunning.

What do you think the voltage of lightning is? Pause here and share with someone.

Thanks for sharing.

A typical lightning volt is 1 billion volts.

Oh my.

Pause here and share with someone have you seen lightning and when did you last see lightning, if so.

Thanks for sharing.

Sofia wonders if the voltage of the cell or battery affects how a circuit works.

What do you think? Pause here and share with someone.

Thanks for sharing.

Here's Jun: "I might try different voltage cells and batteries in my circuit to light the bulb and observe what happens." Sofia would like to investigate Jun's idea, but is worried.

"We only have one type of cell, so I can't investigate different voltages." What could Sofia do? Pause here and share with someone any ideas.

Thanks for sharing.

You could change the voltage in a circuit by using different numbers of cells.

One AA cell provides a voltage of 1.

5 volts.

How much voltage do you think two AA cells would provide? Pause here and share with someone.

A battery of two AA cells provides a voltage of three volts.

Perhaps that's what you shared.

1.

5 plus 1.

5.

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

Some larger cells we use at home are actually batteries because they consist of multiple cells working together.

Remember, a battery is the term we use when two or more cells work together.

This image shows the inside of a nine volt battery, which contains six 1.

5 volt cells.

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

Let's have a check for understanding.

What does adding more cells do to the voltage of a circuit? Is it A, the voltage is higher, B, it does not affect the voltage, or C, the voltage is lower? Pause here while you decide.

What does adding more cells do to the voltage of a circuit? Well done if you selected answer A.

Adding more cells to the voltage of a circuit makes the voltage higher.

Let's have another check for understanding.

Cells or batteries with a higher voltage.

Complete the sentence with one of these options.

A, provide a weaker electrical push in a circuit, B, do not affect the electrical push in a circuit, or C, provide a stronger electrical push in a circuit.

Pause here while you decide which of these endings to use to complete your sentence.

Well done if you selected answer C.

Let's read the whole sentence.

Cells or batteries or batteries with a higher voltage provide a stronger electrical push in a circuit.

Well done if you completed the sentence in this way.

And now it's time for your next task.

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

Here's Sofia: "To change the voltage in a circuit, we need cells and batteries with different voltages." And here's Jun: "To change the voltage in a circuit, we need to use different numbers of cells." Who is correct and why? Pause here and have a discussion about this.

I'll see you when you've had your discussion.

It's good to be back with you.

So how did you get on with that discussion task? Who is correct and why? Perhaps you said that both children are correct.

So here's Sofia: "To change the voltage in a circuit, we need cells with different voltages." This is correct.

And Jun: "To change the voltage in a circuit, we need to use different numbers of cells." This is also correct.

You can change the voltage in a circuit by using cells with different voltages or different numbers of cells.

Both of these are great options.

Well done if you had a discussion about both children being correct.

And now we're onto our next learning cycle, investigating voltage.

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

Here's a scientist: "To affect something is to change what it does or how it behaves." It's important that electricity is safely transported at the correct voltage to our homes and within our appliances.

Studying voltage helps scientists and engineers work together to design better cells and batteries that last longer or are easier to carry.

Understanding voltage is important in medical science to make sure that people are not hurt by medical equipment.

And here we can see some electrical medical equipment.

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

Sofia wants to know how voltage affects how her circuit works.

So here's Sofia's circuit, and here's something she's wondering about.

"I wonder if the bulb in my circuit will get brighter when I increase the voltage." Her friends have come up with some questions.

Sam: "Does a higher voltage make the electricity flow faster?" Jun: "What is the best voltage for my circuit?" And Izzy: "Does the voltage affect the brightness of the bulb?" Which of these should Sofia choose for her inquiry question? Pause here while you decide.

Well done if you selected Izzy's question.

Indeed, this is a great question for Sofia's inquiry.

Does the voltage affect the brightness of a bulb? Let's have a check for understanding.

Scientists plan different types of to find answers to questions.

Fill in the missing word in a sentence with one of these options.

Either A, equipment, B, conclusions, or C, inquiries.

Pause here while you complete the sentence.

Well done if you selected C, inquiries.

Let's read the whole sentence.

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

Well done if you completed the sentence in this way.

Let's have another check for understanding.

Which of these questions could be answered with a scientific inquiry? A, which cell is the best one for my buzzer? B, which buzzer is the loudest? C, which are more popular buzzers or motors? D, which motor is the fastest? Pause here while you decide which of these questions could be answered with a scientific inquiry.

Well done if you selected questions B and D.

These are questions which could be answered with a scientific inquiry.

The children begin to plan their inquiry to find answers to their question: Does the voltage affect the brightness of a bulb? They think about the variables in their investigation.

Here's Izzy: "Remember to only change one variable so we can see the effect of this on the results." Which variable do you think they should change? Pause here and share with someone.

Thanks for sharing.

Sofia will change the voltage of the cells or batteries in her circuit.

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

What will Sofia observe or measure? Pause here and share with someone.

Thanks for sharing.

Sofia will observe the brightness of the bulb.

How could she do this? Pause here and share any ideas.

Thanks for sharing.

Here's Sofia: "I will observe how brightly the bulb shines each time using my eyes." Let's have a check for understanding.

Which of the following do you need to do when planning an inquiry? A, research variables, B, sort and group variables, C, identify and control variables.

Pause here while you decide which of these you need to do when planning an inquiry.

Well done if you selected answer C.

Indeed, you need to identify and control variables when planning an inquiry.

And now it's time for your task.

I would like you to plan an investigation to answer Sofia's question: Does voltage affect the brightness of a bulb? I'd like you to discuss and record what equipment you will need, what you will do, which variables you will change, which variables you will control, and what you will measure and how you will measure it.

So pause here while you have a go at this task of planning your investigation to answer Sofia's question.

I'll see you when you're finished.

It's good to be back with you.

How did you get on with planning an investigation to answer Sofia's question? Your plan may be similar or different to this.

A bulb, a range of cells, wires, a switch, a voltmeter, and a ruler are needed.

A circuit will be set up with a bulb and a cell.

The voltage of the cell will be changed, and the brightness of the bulb will be observed and recorded at each voltage.

The voltage of the cell will be changed.

The type of bulb, the wires used, and the type of cell will be controlled.

The brightness of the bulb will be measured by observing how brightly it lights up.

Well done for having a go at this task and planning your investigation.

In our lesson Investigating voltage: plan, we've covered the following.

A cell is a single unit that is needed for electricity to flow around a circuit, and a battery is two or more cells working together.

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 in series provides a higher voltage and a stronger electrical push in a circuit.

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

Well done, everyone, for joining in with this lesson.

It was so great to investigate voltage together to make our own plan to follow up our line of inquiry.

And I hope you've enjoyed this lesson.

I really enjoyed teaching you.

And I look forward to seeing you at another lesson soon.

Until then, stay curious.