Hi everyone.

It's Ms. Panchal here.

I'm really glad and excited you've decided to join me on our science lesson today.

We've got lots of learning to do today in our lesson.

So our lesson today is part of our bigger unit of learning all about properties, changes and separating materials.

And so we're going to focus particularly today on burning and how that is an irreversible change.

Now, some of you might already know what irreversible means, but don't worry too much if you're not sure 'cause we're going to go through lots of examples in our lesson today.

Let's get started.

So the outcome for our lesson today is I can describe burning as an irreversible change or a new material is formed.

So as I said, you might already know what the word irreversible means or you might not be so sure, but don't worry because that's what the lesson today's about.

So at the start of our lesson, we're just gonna recap on some key words.

So what I'd like you to do is pause the video here and with your talk partner, can you take in turns to say the key word, but also read out the definition aloud to your partner.

Once you've read out these keywords and definitions, click play and we'll start with the lesson.

Off you go.

Great reading everyone.

Well done.

So we'll come across lots of these keywords in our lesson today.

So today's lesson is combining two different parts together.

So we're first going to think about burning itself, and then we're going to move on to looking at burning as an irreversible change.

So let's get started with the first part of the lesson where we're focusing purely on burning and learning about what it is.

So Jacob and Izzy observe a bonfire at their local firework celebration.

Now, some of you may have been to a bonfire before and I know that, I'm Hindu and we have a festival called Holy and that is also incorporated with a bonfire.

So you may have seen bonfires in different circumstances or different situations.

So they know that the bonfire is made by gathering wood and making it burn.

Jacob says, "I burnt my toast in the toaster this morning, but it didn't make a bonfire.

So what is burning?" So that's what the first part of our lesson today is focusing on actually learning about what burning actually is.

So, do you know what burning is? So pause the video here, have a little bit of thinking time on your own, and then I want you to share your ideas with your partner.

And then once you've done that, share your ideas with the rest of the class.

So, what do you know about burning? Great ideas everyone.

Well done.

So Izzy says, "Is burning the same as melting?" Jacob says, "Is burning the same as heating?" So we've got a few different examples here.

We've got wood burning, we've got ice cream melting, and we've got water being heated.

Burning is not the same as melting or heating, and that's something that's really key for today's lesson and it's really important that we understand that.

So burning is different from melting and heating.

They're not the same.

So heating is raising the temperature of a material.

Melting occurs when the temperature is raised enough to cause a material to change from a solid state to a liquid state.

So if we have a look at this example here, we've got a solid ice block, and if we heat it, it's going to melt and it will turn into liquid water.

So initially it was in a solid state, but it's now in a liquid state.

The material is still the same, it's just in a different state.

So initially it was a solid, but now it's liquid, but the material is actually still the same.

If you cool down the material, it will freeze changing back from a liquid state to a solid state.

So if we had that glass of liquid water, we could freeze it, which would be cooling it, and it would actually turn back into solid ice.

So it would go from a liquid back to a solid.

So we can go from a solid to a liquid through heating and melting, and then from a liquid back to a solid through freezing, which is cooling.

So we can see here that the material is exactly the same, but we are just changing the state of the material.

Melting is a reversible change.

So this melting here because we can go back to the original state.

So we'd say here that melting is a reversible change.

So when a substance burns, it can produce a flame, and you may have seen this before.

Some materials burn very easily, such as wood on the bonfire.

So if you're going camping, for example, you need wood in order to make your bonfire and you'll be able to make your fire, maybe to cook your food on and using wood would be a quick way to light your fire.

Izzy says, "But what causes a material to burn?" So for burning to take place, there has to be a fuel, oxygen and heat.

So this is sometimes shown in a diagram called a fire triangle.

So as part of the fire triangle diagram, you've got oxygen, heat, and fuel.

So all three of those things are needed for burning to take place.

And if one of those things isn't present, then burning will not take place.

Can you think of any examples where burning takes place? So pause the video here and have a little think with your talk partner and jot your ideas down on a whiteboard.

Can you think of examples where burning takes place? And remember, for burning to take place, you need oxygen, heat, and fuel.

Pause the video here, jot down your ideas on a whiteboard and then share with your partner.

When you're ready to continue, press play.

Great job everyone.

Well done.

So the bonfire, which Izzy and Jacob saw was an example of burning.

Izzy says, "What are the three parts of the fire triangle for the bonfire?" Can you remember? Excellent, well done.

The wood was the fuel, the oxygen was from the air and the heat was from a match.

So remember, in order for burning to occur, we need three things in place.

We need fuel, oxygen, and heat.

So let's do a quick check of our learning.

So when a substance burns, it often produces, A, oxygen.

B, a flame.

C, a bonfire.

What do you think? Great job.

B, a flame.

So when a substance burns often produces a flame.

So one way to stop burning is to use water to bring down the temperature.

And this is why firefighters often use water to try to put out fires.

So we've got a picture here of firefighters using water to put out a fire.

So one way to stop burning is to prevent oxygen reaching the fire.

And remember, oxygen is one of the things needed in order for burning to happen.

So one way to stop the burning is actually to prevent the oxygen from reaching the fire in the first place.

We can do this by using fire blankets, foam fire extinguishes, and also shutting doors and windows.

So you may have seen these different things around the room that you are, maybe at school and at home.

And so these different things here can actually prevent oxygen from reaching the fire, which means it will help prevent burning or even any fire spreading.

So let's do a check of our learning.

Which of these are necessary for burning to take place? A, sticks.

B, heat.

C, fuel.

D, oxygen.

So pause the video here if you need to go back to over the last couple of slides to recap on what things are necessary for burning to take place.

I'll give you a clue.

There are three things that are needed for burning to take place.

Once you've thought of your answer, click play and we'll go through the answer.

Great job.

There are the three things here that we need.

So we've got heat, fuel, and oxygen.

So all of these things need to be present in order for burning to take place.

Let's do another check of learning.

Why do people shut doors when there is a fire? A, because fires cannot go through doors.

B, to reduce the oxygen available to the fire.

And C, to keep the fire tidy.

So pause the video here, if you need to go back over the last few slides to think about why people shut doors when there's a fire to help you answer the question, what do you think A, B, or C? Great job.

So the answer is B, to reduce the oxygen available to the fire because we know that oxygen is one of the components needed in order for burning to occur.

So if we reduce the oxygen available, it would mean that it would help to stop the fire, but also to prevent it in the first place.

So let's move on to the first task.

So I would like you to complete the table to identify the fuel and the heat source.

So let's read through the examples.

So we've got natural forest fire, fire started by rubbing sticks together, a burning match and burnt toast.

So you need to think about for each of these examples, what's the fuel and what's the heat source.

So if you'd like to, you can print out this slide or you can draw your own version, completely up to you.

I'd like you to complete this table and then click play when you're ready to continue and we will go through the answers.

If you need to go back over the learning we've done so far in the lesson just to recap on the three components needed for burning to occur.

Great job everyone.

Well done.

So let's go through the answers.

So for the natural forest fire, the fuel would be the wood and the leaves and the heat source would be the sunshine.

Now there's lots of forest fires that happen in lots of hot countries.

For example in Australia there's lots of forest fires that happen there.

Next example is fire started by rubbing sticks together.

The fuel would be wood and the heat source would be a contact force which is friction.

The next example is a burning match.

So the fuel would be the materials in the match head and wood.

And the heat source would again be the friction, which is the contact force.

In the last example with the burnt toast, the fuel would be the bread and the heat source would be the heat from the toaster.

Did you get those answers? Well done for having a good go at this task everyone.

Good job.

So we've completed the first part of our lesson where we've learned more about what burning actually is and what it involves.

So we're now going to use that knowledge to help us understand burning a little bit further.

And we're going to focus on burning being an irreversible change.

So Izzy says "I could smell the bonfire before I could see it." And Jacob says "At the bonfire, I could see a lot of grey smoke in the air above the flames." When things burn, new materials are usually formed and burning produces new materials such as carbon dioxide, water, solid ashes and smoke.

But Jacob says, "Is smoke the same as the steam that comes outta the kettle when we boil the water?" What do you think? Pause the video here, have a think about what Jacob's asking.

What do you think about it? Good job everyone.

So smoke and steam are not the same.

Steam is water in the gas state and it's produced by boiling water.

You might see this when you are making a hot drink, maybe for an adult.

If you are pouring boiling water out of your kettle, you'll seem steam and that is water in the gas state.

Whereas smoke is a mixture containing tiny solid particles of different materials for water vapour and gases.

So we can see here that smoke and steam are not the same.

In appearance they may look the same at times, but actually they're both very, very different.

So Jacob and Izzy went back to the bonfire the next day.

Izzy said, "All the wood had gone." And Jacob said, "All that was left was grey ash on the ground and it was a flaky solid." "I've been learning about reversible changes in science.

So when you have burned something, how can you get the original material back?" So we would describe burning as an irreversible change.

And irreversible changes are changes where the original material cannot easily be recovered and new materials are made.

So we've got the wood here for burning will end up with ash and smoke.

So ash and smoke are new materials which are formed when wood is burned and burning is a change that cannot be reversed.

We can't make wood from ash and smoke.

So let's just break down this diagram and examples here a little bit further.

So we've got the wood and the wood is then burning to create then ash and smoke.

So these are the new materials that have been made, but what we cannot do is we cannot put the ash and the smoke together and it would make wood, that would not happen and that cannot happen.

Therefore, we would say that burning is an irreversible change because it creates new materials, but also we cannot put the ash and smoke together to make wood.

Jacob says, "But what actually happens when something burns?" So burning materials can be observed as they change over time.

Jacob and Izzy want to observe burning but are worried that it might not be safe.

"You could get burned if you touch something hot or the flame." Or "You could even start a fire." So you have to be really, really careful.

Jacob and Izzy are correct.

Burning can be very dangerous, but if you follow rules you can observe a burning safely.

So Jacob and Izzy here make a fire safety tray by filling a metal tray with sand.

They place a tea light in the middle of the tray.

Izzy says, "I want to hold different materials in the flame but my fingers will get hot." And that is very dangerous and you should not do that.

What could Izzy do though to be safe? So Jacob and Izzy want to explore and observe birding safely, but Izzy cannot hold the materials with her fingers because they'll get too hot and she could be in the risk of hurting herself.

So what could Izzy do to be safe? Great.

So there's lots of other equipment that Izzy can use to help her in order to make sure that her fingers do not get hurt.

So you can use tongs to hold hot items. We've got metal tongs here.

They are long so that you can keep your hand a long way from the flame.

But Jacob says, "These tongs are made of metal and I know that metal conducts heat.

So won't my hand get too hot?" So Jacob has used his knowledge from previous years of science learning that the metal here conducts heat, which means the metal tongs would actually get hot.

So what do you think he could do? Well actually, because the tongs are quite long and the heat from the investigation is not very high 'cause they're only using a tea light, it's actually unlikely that there'll be much heat that will travel along Jacob's hand.

So in this case and in this example, using the metal tongs would be safe.

So Jacob holds a piece of twisted paper in the tongs.

He lights the paper using the tea light that moves it away from the flame and holds it over the sand.

Just like in the example photo here.

Jacob and Izzy observe the paper as it burns, then put any remaining pieces safely in the sand.

Izzy says, "I observed the paper turning black and curling." And Jacob says, "The flame was the first thing I observed." Let's do a check of our learning.

Which of these is true about burning? A, it produces new materials.

B, it produces the same materials in a different state.

Or C, it sometimes produces new materials and sometimes results in the same material.

So pause the video here, have a think about the learning we've done about burning and which answer do you think is true? A, B, or C? Great job.

The answer is A.

So it produces new materials.

So we've spoken about burning and the fact that it's an irreversible change because new materials are made, but also those new materials cannot go back to the original material that was used to burn.

Let's do another question.

True or false? Burning is a change that can be reversed.

True or false? What do you think? Great job.

The answer is false.

Now we need to think about why it is false.

Do we think because, A, burning produces new materials and it's hard to get the original materials back.

Or, B, burning produces new materials and you cannot get the original materials back.

What do you think A or B? Great job.

The answer is B.

So we've learned here that burning produces new materials and you cannot get the original materials back.

Great job everyone.

Let's do another question.

Burning materials can be.

as they change over time.

So what is that missing word for this sentence? Is it A, lit? B, observed.

C, reversed.

So I'll read the sentence again to you.

Burning materials can be.

as they change over time.

So what is the missing word for that sentence? A, B, or C, what do you think? Great job.

The answer is B, observed.

So burning materials can be observed as they change over time.

Good job everyone.

So let's move on to the next task for the task for this lesson.

So observe how paper burns using Jacob and Izzy's method.

Prepare a tray of sand before you begin.

Now, before I go through the instructions for the task, it's really important that you are safe and seek adult help as well when setting this all up.

So the first part is ask an adult to light the tea light for you.

And then the second step is to tightly twist a piece of paper and grip it to the tongs.

The third step is to then use the tongs, hold the paper over the flame, and once it's lit, move the paper away from the flame, but still over the sand tray.

And I'd like you to observe what happens to the paper and what is left of it at the end.

So follow the steps here to do this observation activity, but please remember to be careful and ask an adult to help you.

Off you go.

And I look forward to hearing about all the observations you made.

Great job everyone.

Well done.

And well done for following these steps and being careful and being safe.

So you may have found these observations too.

First, the end of the paper went brown and flames appeared.

Next, smoke was produced too.

The end of the paper went black and then grey and began to fall off.

Next, the burning moved along the paper up towards the tongs, and at the end all that was left was grey ash.

A new material has been produced and we know that when a new material has been produced, this is an example of an irreversible change.

Did you get the same observations or did you get some slightly different observations? Well done for having a good go at this task everyone.

So we've come towards the end of our lesson today all about burning and understanding that it's an irreversible change.

So let's do a summary of our learning.

When a substance burns, it produces a flame.

And for burning to take place, there has to be fuel, oxygen, and heat.

When things burn, new materials are usually formed and burning is a change that cannot be reversed.

Burning materials can be observed closely as they change over time.

So we've learned a little bit about what burning actually is, but we've also used that learning to help us understand that it's an irreversible change.

Now, amazing work today everyone.

I really, really appreciated your enthusiasm and your ideas that you shared with your partners, but also with the rest of the group as well.

I hope you have a great rest of the day and I'm sure see you in the next science lesson really soon.

Bye-Bye.