Lesson video

Hi, everybody, My name is Ms. Panchal and I'm so excited and glad that you've decided to join me on our lesson today.

We've got lots of fantastic learning to do.

So our lesson today is within our topic of the introduction to light and shadows, and we're going to be focusing on three keywords in our lesson today: opaque, transparent, and translucent.

So you may have heard some of these words before, so you can build on your knowledge.

If you're not sure what the words mean, then please don't worry, 'cause that's what today's lesson is all about.

Let's get started.

So the outcome for our lesson today is I can compare different materials based on how transparent they are.

So we're going to look at some keywords that we're going to use in our lesson today, and some of these words you may already know or heard of before, but some of you might not be so sure on some of them, but please don't worry, because that's what our lesson today is all about.

So you've got the word material, and a material is what an object is made from, and an object can be made from more than one material.

We've got the word classify.

To classify is to sort objects into groups.

And we've got the word opaque.

So opaque means light cannot pass through objects that are opaque.

The word transparent.

Transparent materials are completely see-through.

And we've got the word translucent.

Translucent materials allow some light to pass through but are not completely see-through.

So let's practice saying some of these keywords.

So I'm going to say the word and I would like you to repeat it back to me.

My turn, material.

Your turn.

Well done.

My turn, classify.

Your turn.

Great job.

My turn, opaque.

Your turn.

Super job!

My turn, transparent.

Your turn.

Brilliant job.

My turn, translucent.

Your turn.

Wow, everyone!

Fantastic practice of saying these words.

So our lesson today is split up into two parts.

So the first part of our lesson we're going to be focusing on materials that do not allow light through, and then the second part of our lesson will be focusing on materials that do allow light through.

So, let's get on with the lesson.

Different objects are made of different materials and we can see a picture of a classroom here, and maybe your classroom looks a little bit like this.

Do you know the names of any materials?

So pause the video here.

Maybe look around the room you're in now.

Can you name any different materials?

Have a go.

Super job, everyone.

Well done.

So all around the room, any room that you're in, there's going to be lots of different materials.

Well done.

Aisha says, "These toy building blocks are made from wood.

" Laura says, "My T-shirt is made from fabric.

" And Alex says, "My water bottle is made from plastic.

" Different materials have different properties.

We can classify materials in different ways depending on what properties they have.

But Andeep says, "What does classify mean?

" I think he's not really sure.

Izzy says, "When we classify materials, we sort them into groups.

" Have you done some classifying before?

Maybe you've done it in some of your other science lessons or maybe in some other subjects at school.

These objects are made from materials that can be classified as rough.

So we've got sandpaper, bricks, and hessian fabric.

So if you touched any of these materials here, they'd be quite rough, not very smooth at all.

These objects are made from materials that can be classified as absorbent.

You've got a sponge, kitchen roll, and cotton wool.

For example, if you accidentally spilled some water on the table, you'd put kitchen roll on top of it, and the kitchen roll would absorb the water.

Materials can be classified by how much light passes through them.

Can you name any materials that allow light to pass through them?

So pause the video here, think about all the learning you've already done about light, about shadows, about materials, and think about which materials might allow light to pass through them.

Discuss your ideas with your talk partner.

Are they the same ideas or are they different?

Click play when you're ready to continue.

Super job, everyone.

So, we've got glass flasks here and we've got a plastic cup, and we can see here that these materials here allow light to pass through them and we can see through them.

Let's do a check of our learning.

True or false?

Classifying means sorting things into groups.

Do we think that's true or false?

What do you think?

Great job.

It's true.

Now we need to think about why it is true.

Is it because A, we can classify materials by how much light they let through them; or B, objects are made of different materials?

What do you think, A or B?

Super job.

The answer is A.

We can classify materials by how much light they let through them.

So some materials do not let light pass through them, and we've got an example of wooden blocks here.

Jacob says, "I cannot see through these wooden blocks.

This means that wood does not let light through.

" Do you know the property of materials that do not let light pass through?

We've got an example of a china mug here.

Do you know the property?

Excellent, well done.

So materials that do not let light pass through are called opaque materials.

Why do you think this is a useful property?

So, why do you think it's a useful property for this kind of material to be opaque?

Pause the video here, have a think with your talk partner.

Great job, everyone.

Well done.

So opaque materials can be useful for objects that are required to block out light, such as an eye mask or a pair of curtains.

So if you wear an eye mask to bed, it's important that the material that eye mask is made out of means that no light passes through and so that it can help you sleep.

And the same with curtains.

If we could see through the curtains, then your bedroom, it would be very light, and then it'd be quite tricky for you to fall asleep.

Objects can be tested to find out if they're made from an opaque material.

Jacob says, "I can hold materials up to light and check if light passes through them.

If I can't see through the material, then it is opaque.

" And we've got an example here.

We've got a cardboard tissue box, and we can see that we cannot see through this cardboard tissue box.

Some materials can be tested with a torch to find out if they are opaque.

We've got an example here of a foil which is covering a torch.

Jacob says, "I will dim the lights and cover the end of the torch with a material, either by holding it in front of the torch or attaching it with a rubber band.

Then I will switch the torch on and observe if light passes through the material to shine onto a blank wall.

" Jacob says, "If we can't see any light shining onto the wall, this tells us that the material is opaque as no light is passing through it.

" So we can see Jacob's example here.

So we've got the material covering the end of the torch, which he's used aluminum foil for, and you can tell that he's wrapped it onto the end of the torch where the light is.

But we can see that actually, there's no light shining on the wall there.

So, what does that tell us about aluminum foil?

Well done, that it's an opaque material.

So let's do a quick check of our learning, shall we?

True or false?

Opaque materials let light pass through them.

Do we think that's true or false?

Excellent work.

The answer is false.

Why do we think it's false?

Do we think A, we can see through objects that are made from opaque materials; or B, we cannot see-through objects that are made from opaque materials?

What do you think, A or B?

Super job, everyone.

Well done, the answer is B.

We cannot see-through objects that are made from opaque materials.

Well done, everyone.

Let's do another check of our learning.

Which of these objects is made from an opaque material, a glass, a plastic bottle, or a metal spoon?

So think really carefully about what the word opaque means.

If you need to, go back over the last few slides to recap your learning before you answer this question.

When you've thought about it, click play and we'll go through the answer.

Super job, everyone.

The answer is C, because the glass we can see through, it lets light through, and same with a plastic bottle.

With a metal spoon, that is not correct.

So well done, everyone.

The metal spoon is made from an opaque material.

So let's move on to the first task of today's lesson.

So I would like you to use Jacob's method to test materials and find out if they are opaque.

So the first step is to place a material sample in front of the torch and then dim the lights in the room that you're in.

The third part is to point the torch at a blank wall and then turn on the torch and observe the wall for any light passing through the material.

So this is an example of what your setup should look like.

So we've got a torch, we've got material around the end of the torch, and we're going to be able to see on the blank wall if there is light there or if there is not, and that will be able to tell us whether the material is opaque or not.

Here is another example of a material being used where it is not opaque, because light has been able to pass through.

Testing materials to find out whether they are opaque or not.

So materials to test are plastic crisp packaging, aluminum foil, cling film, cardboard, tracing paper, and a clear plastic bag.

You may need an adult to help you to collect these different materials.

Once you've collected them, you can start exploring and testing them.

If you'd like to, you can use the table that's on the screen here and split it up into two columns, opaque and not opaque, or you can jot down your ideas on some post-it notes and arrange them on your table.

Off you go.

I hope you have a great time testing your materials, and I can't wait to hear about your results.

Off you go.

Excellent work, everybody.

Well done.

So you may have tested different materials to these, but if you use the ones in the example, you may have got these results.

So the opaque materials are plastic crisp packaging, aluminum foil, and cardboard; and the not opaque materials are cling film, tracing paper, and a clear plastic bag.

Did you use these materials or did you test some different ones?

Well done for having a good go at this task, everyone.

Well done.

So we're going to focus now on materials that allow light through.

So some materials do let light pass through.

Jun says, "I observed that light from the torch shining on the wall.

This must mean that the material covering the end of the torch was not opaque because light passed through.

" So we can see an example here of the material covering the end of the torch, but actually the light is still passing through and that's why we can see the light on the wall.

Lots of objects and materials we use every day are not opaque.

We've got an example of Sofia's bottle here.

Sofia says, "My bottle is not opaque.

I can see through it because the material lets light pass through.

" And we can call materials that let light pass through them see-through.

So we've got an example here of see-through glass vases.

Alex says, "Do you know another word that we can use to describe these materials?

" Pause the video here, have a little bit of thinking time on your own, and I would like you then to share your ideas with your partner.

Do you know another word that we can use to describe these materials that we can see through?

What do you think?

Fantastic work, everybody.

Well done.

So materials that are see-through can also be called transparent, and transparent materials allow light through so objects can clearly be seen through them.

Now, transparent is another one of our keywords today, so we're going to practice saying it again.

My turn, transparent.

Your turn.

Excellent, say it again for me.

Brilliant work, everyone.

So Alex says, "The lenses in my glasses are transparent," and exactly the same in my glasses too.

"I can see through them clearly.

" When would transparent material be useful?

So when might it be useful to be able to see through a material?

Have a think with your talk partner.

Excellent work, everyone.

So transparent materials can be useful for objects that we want to be able to see through or that we want to let light through, such as glass in a window or a measuring jug.

Let's do a quick check of our learning, shall we?

True or false?

Transparent materials let light through so objects can clearly be seen through them.

Do we think that's true or false?

Super job.

The answer is true.

Now let's think about why it is true.

Do we think because A, objects like curtains and eye masks are often made from transparent materials, or B, objects like windows and measuring jugs are often made from transparent materials?

Which one do you think is correct, A or B?

Have a little think.

Super job, everyone.

The answer is B.

So objects like windows and measuring jugs are often made from transparent materials.

So windows, we obviously want to be able to see through them, but also for measuring jugs.

If you are baking a cake and you need to measure the milk out, for example, you need to be able to see on the scale where the milk comes up to, if it's gone to the correct amount or you need to add a little bit more.

Let's do another quick check of our learning.

Which of these objects is made from a transparent material?

A, a kettle; B, oven door; C, bins.

Pause the video here, and if you need to, go back over the last couple of slides to recap on what the word transparent means.

When you're ready to go through the answer, click play and we'll talk through it.

Off you go.

Excellent job, everyone.

Well done.

It's B, the oven door.

So we know that the oven door is made from a transparent material because it lets light through and we can see through it.

So for example, you've got your delicious cake cooking in your oven, we need to be able to see through it and see the cake cooking inside.

Whereas the kettle, we cannot see through inside the kettle, so it's made out of a material that is not transparent.

And same with the bins.

It does not let light through and we cannot see inside.

Well done, everyone.

Sam says, "What about my bathroom window?

It allows light through, but I cannot see objects clearly through it.

Is it opaque or transparent?

" What do you think?

Hands up for it's opaque, or hands up if it's transparent.

Hmm, let's have a little think.

So Lucas says, "When I look at the window, I can see light coming through, so I think it's transparent.

" But Sofia says, "When I look at the window, I cannot see any objects through it clearly, so I think it's opaque.

" Is there another property to describe the material of this window?

Have a little think with your talk partner.

Well done, everybody.

So some materials allow some light through but objects cannot be seen clearly, and these materials are called translucent.

Now, this is another really key word for our lesson today, so let's practice saying it.

My turn, translucent.

Your turn.

Excellent.

Now can you whisper it to your partner?

Translucent.

Excellent, well done.

So we can see a picture here of some tulips in translucent packaging, and tulips are my favorite.

Do you observe any translucent materials in the room where you are?

So pause the video here and have a little look around you.

Can you see any translucent materials?

Super job, everyone.

So translucent materials are useful for objects that we want to let some light through, but not all.

This plastic bag and plastic pot lets a lot of light through, but we cannot see objects through them clearly.

So we can see the plastic bag here.

It does let light through, but actually we can't see clearly through it, and exactly the same with the plastic pot.

So we would say these objects are made from translucent materials.

Alex says here, "My water bottle is made of pink colored plastic, but I can still see through it.

Does this mean it is transparent or translucent?

" What do you think?

Pause the video here, and I want you to have a little bit of thinking time on your own and then share your idea with your partner.

What do you think about what Alex is saying?

Excellent job, everyone.

So Lucas says, "When I hold your bottle up to the light, I can still see objects clearly through it, so it must be transparent.

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

Who do you agree with?

Laura says, "Materials that are translucent do not let any light through, so we can't see through them.

" Jacob says, "Materials that are translucent let light through, so we can see through them clearly.

" And Andeep says, "Materials that are translucent let some light through, so we can see through them but objects cannot be seen clearly.

" So have a little think about what we've just learnt about translucent materials, and if you need to, go back over the last few slides.

Who do you agree with, Laura, Jacob, or Andeep?

Excellent work, everyone.

Andeep is correct.

So Andeep has said that materials that are translucent let some light through and we can see through them, but objects cannot be seen clearly.

Well done, everyone.

So let's move on to the next task.

So I would like you to test the materials from Task A that were not opaque to classify them as transparent or translucent.

So in the first investigation for the lesson, you were testing different materials.

And so you're going to focus on the ones that were not opaque, and now we're going to group them and classify them as transparent or translucent, as we've now learnt what those two words mean.

Andeep says, "Hold each material up to light.

Can you see objects clearly through it?

" So some materials that you might like to test are plastic crisp packaging, aluminum foil, cling film, cardboard, tracing paper, and clear plastic bag.

So these are the materials you tested in the first investigation for our lesson.

So the ones that were not opaque, you're going to be classifying them as transparent or translucent.

So have a go at testing the materials and I look forward to hearing all about your results.

Off you go.

Fantastic work, everybody.

Well done.

So the task was to test the materials from Task A that were not opaque to classify them as transparent or translucent.

So, you may have tested some different materials, but based on the first investigation, the transparent material would've been cling film and the translucent materials would've been clear plastic bag and the tracing paper.

Did you get the same results or did you get some different ones?

But well done for having a good go at this investigation.

So, I'd like you to now move on to the next task.

So I would like you to find objects around your home or school that are made from opaque, transparent, or translucent materials.

So you've looked and studied all those three keywords in our lesson today.

So you can use this example table or you can draw your own.

So find different objects that are made from opaque, transparent, or translucent materials and write them down on this table.

If you'd like to, you can jot this table down on a whiteboard or even use post-it notes too.

Now, please be very careful if you're handling and carrying objects made from glass, as they're very fragile.

Have a go at this investigation, and I look forward to hearing about all the different objects you found.

Fantastic work, everybody.

Well done.

So, here are some examples.

In opaque, you may have found a plastic toy brick, wooden block, a book, and a laptop.

For transparent, you may have found magnifying glass, glasses lens, glass jug, clear pencil case.

And for translucent, you may have found clear plastic bag, tracing paper, or baking paper.

Maybe you found similar objects to this or maybe you found some different ones, but well done for having a good go at finding different objects and classifying them into opaque, transparent, or translucent materials.

Well done, everyone.

So, we've come towards the end of our lesson today, so let's do a recap of our learning.

So we've learnt the materials can be compared and classified according to how much light can pass through them.

Opaque materials do not let light pass through them, and transparent materials allow light through so objects can clearly be seen through them, but translucent materials allow some light to pass through but are not completely see-through.

So we've got our three keywords there for today's lesson, and let's just practice one last time saying them.

My turn, opaque.

Your turn.

Super.

My turn, transparent.

Your turn.

Excellent job, well done.

My turn, translucent.

Your turn.

Fantastic job, everybody.

Well done.

I'm so impressed with all of your learning today and all of your ideas and suggestions.

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

Bye-bye.