Hello, my name is Mrs. Mehrin, and I'm really excited to be learning all about rusting, which is an irreversible change with you today.

Hello, and welcome to today's lesson from the unit Properties, Changes and Separating Materials.

Your learning outcome is, "I can describe rusting as an irreversible change where a new material is formed." Now I know that learning can sometimes be a little bit challenging, but that's okay because it just means that we are going to work really hard together and we're going to learn lots of fabulous new things.

Let's begin.

So here are your four keywords for today.

Alongside these keywords are the definitions.

I'm going to be referring to these throughout today's video.

However, if you find it helpful, you can pause the video here and you can jot these down.

Fantastic, well done.

Now your lesson today is split into two parts.

Let's begin with the first part, rust.

Now Jun and Aisha are trying to raise money to buy new tools for their gardening club.

Jun says, "The old tools are no longer shiny and the paint has come off.

There are some patches of brown, which look rough and bumpy." Aisha says, "The wooden handles are fine, it's just the metal that has changed." Now what has happened to the metal parts of the tools? I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

So what do you think the brown substance is on the metal parts of the tools? Again, I'll give you five seconds to think about your answer, off you go.

Fabulous, well done.

So the metal parts of the tools have rusted, and rust is reddish brown in colour and has a rough texture.

And Aisha says, "I can see what rust looks like, but I don't know why it's formed." Do you know? I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

So before we go into that, let's do a quick check-in of your learning.

Rust can have a rough texture, but what colour is it? Is it silvery grey, greenish blue, reddish brown or pinkish purple? I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

It's reddish brown.

Now rust is a new material that is formed when iron or steel is exposed to water and oxygen in the air.

So iron and steel plus water plus oxygen equals rust.

Now rusting is the name of this process and rusting does not happen instantly, it takes time.

Now we can see rust on many metal objects we use in everyday life.

Where have you seen rust before? I'll give you five seconds to think about your answer.

Off you go.

Fabulous, well done.

So you might have said things like bike brakes, chain, gears, padlocks and tent pegs, and all of these items rusted because they're made from iron or steel and were exposed to moisture, so water and oxygen in the air.

Now Aisha says, "Do all metals rust?" And Jun says, "We have aluminium pans in our mud kitchen, but they are left outside in the rain.

Will they eventually rust?" Now other metals don't rust, they become dull when they are exposed to water and oxygen in the air, but they don't rust.

Iron and steel are the only metals which rust, and steel rusts because it contains iron.

Now let's do a quick check-in of your learning, which of these combinations could lead to rust being formed? Iron or steel plus oxygen, iron or steel plus water, or iron or steel plus oxygen and water.

I'll give you five seconds to think about your answer.

Off you go.

Fabulous, well done, it's C.

Now Jun is trying to decide where to store the new steel gardening forks.

Where should he store them? I want you to explain your answer.

So he's got this new gardening fork, do you think he should keep it under a covered outside area, in an outside storage shed, or in a cupboard in the classroom? So think really carefully here.

If he's got a new steel gardening fork and we know that iron and steel can rust, think about what conditions need to be present in order for it to rust.

Where would be the best place for Jun to keep this new gardening fork to make sure that it doesn't rust? So I want you to pause the video here and I want you to have a go at this and then I want you to explain your choice.

Why have you chosen that place to store the gardening fork? Okay, off you go.

Fantastic, well done.

So if Jun wants to stop the tools rusting, he should store them either in the outside storage shed or in the cupboard in the classroom.

If the shed is dry, then that's the best place for it.

Tools would rust in a damp shed or under the cover of the outside play area because they could be exposed to oxygen and water in the air.

So you remember we need both of those, we need the oxygen and we need the water in order to create that rust.

Now the indoor cupboard is most likely to have no water in the air, but hopefully the shed won't either.

So you would have to go and have a look at the conditions of the shed before keeping that new gardening fork in there.

Now we are on to the second part of our learning, which is making observations over time.

So Aisha says, "We had rusty railings outside our house, but my mum rubbed the rust off with sandpaper." And Aisha says, "I think she reversed the rusting because the metal underneath the rust was shiny again afterwards." What do you think? I'll give you five seconds to think about your answer.

Off you go.

Fabulous, well done.

So Aisha's mom hasn't reversed the rusting, she rubbed the rust off to reveal new iron underneath, and then she's painted it black to protect the iron from the moisture in the air.

Rusting is an irreversible change.

So what that means is that you cannot reverse it.

So that rust that appeared on these railing, Aisha's mum has just rubbed them off, she hasn't managed to make that railing go back to the way it originally was, she's just rubbed off the rust and underneath is new iron.

So this means that the material cannot usually be changed back to the original material.

Now let's do a quick check-in of your learning.

It says, "Rusting is an irreversible change because," A, it involves a metal and carbon dioxide, B, the process cannot easily be undone and new materials are formed, or, C, the original material can be easily recovered.

So I'll give you five seconds now to think about your answer, off you go.

Fantastic, well done, the answer is B.

Now Jun and Aisha would like to find out more about rusting, and Jun says, "I wonder how quickly rusting happens." How do you think they could study this? What could they do to see how quickly rusting happens? I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

So scientists often make observations over time and it can help them to identify patterns and changes.

Now, some investigations involve observations over short time timescales, such as your pulse and how your pulse rate slows down after you do exercise.

That's something that you can do in a very small amount of time over a short timescale.

But some investigations involve observations over longer timescales, like how plants grow after germination.

And some studies involve observations made over hundreds of years, like changes in global temperatures and climate.

Now rusting materials can be looked at closely as they change over time using observation skills.

So here we've got a steel wool pad.

And Jun and Aisha could observe how the colour and texture of steel cleaning pads changes over a number of days or weeks.

So they decide to observe rusting in a steel wool pad.

And here we have a dry steel wool pad in a bowl.

So what they do is they dip the pad in water and then they put it in a bowl on the side.

And in another bowl, they just put a dry steel pad, like the one in the picture here.

And each day for one week, the children make observations of both pads.

So remember, one is now exposed to water and air, and the other one is dry.

It is exposed to the oxygen in the air, but it is dry.

So let's do a quick check-in of your learning before we continue with our learning today.

So rusting materials can be looked at closely as they change over time.

Now what skills would this involve? Would it be, A, measuring, B, predicting, C, concluding, or, D, observing.

So think about the question, there's a clue in the question.

Rusting materials can be looked at closely as they change over time, what skills would this involve? So I'll give you five seconds to think about your answer.

Off you go.

Fabulous, well done, so the answer is D, observing.

So here is your second task for today.

It says, "Carry out the children's investigation." So you're going to set up the investigation.

You're going to dip a steel wool pad in water and then put it in a dry bowl.

You're going to place a dry steel wool pad in another bowl making sure that that other bowl is dry.

So you don't want any water in that second bowl, and you're going to make observations every day for one week.

So in order to make the observations, you may choose to take photographs and record observations which describe the rusting, or you may quantify it using the following method, so.

A, hold a see-through centimetre square grid above each pad and count the number of squares through which rusting is visible.

So you could either take your photographs or quantify it using the method listed here.

So what you're going to do now is you're going to pause this video, you're going to have a go at doing this, and you're going to come back once you have finished, so you are going to have to do this over a week.

So every single day for one week, you need to do this investigation and observe, and then come back to this lesson once you've done that.

So I'd like you to stop the lesson here and have a go, off you go.

Fantastic, well done, and welcome back.

So we took photographs and made observations every day for seven days.

So on day 0, both steel wool pads were completely silvery and shiny.

The dry pad was still like this after seven days, but the damp pad gradually rusted.

So nothing changed for two days, but on day three, the first rust was visible on the damp steel wool pad and the amount increased every day up to seven days.

So now we are onto the summary of our learning for today.

So rust is reddish brown in colour and has a rough texture.

Rust is a new material that is formed when iron or steel is exposed to oxygen in the air and water.

Rusting is an irreversible change whereby the original material cannot easily be recovered.

Rusting materials can be looked at closely as they change over time using observation skills.

You have worked really hard and you've done some fantastic observations.

Well done.