Hello, everyone.

This is Mr. James.

I'm really happy to be with you today for a science lesson.

So, pack your bags.

We're off to planet curiosity! Today's lesson is from the unit Introduction to Sound, and the title of our lesson today is Vibrations and Solid Materials.

Here's our learning outcome.

By the end of today, it would be wonderful if you could explain how sounds can travel through a solid medium to our ears.

That's our learning outcome for this lesson.

So, let's get started.

We have some key words, some science key-words that will help us to explain our understanding to others.

So, I'll read them to you.

I'll leave a little gap, so if you want to repeat them, you can.

So, today's words are vibrations, medium, solid, taut, conclusion.

Be careful, though, because words can sound the same but have different meanings, like the word taut; when your teacher taught you a lesson.

Is that spelled the same here, or could this be a different taut? We shall see.

So, let's have a look at those words and see what they mean.

Vibrations: Vibrations are when an object moves very fast from side to side.

Vibrations need a medium to travel, such as a solid medium, a liquid medium, or a gas medium.

A solid is something that holds its shape and is not a liquid or a gas.

Taut means to be stretched firmly or tightly.

In a conclusion, scientists explain what the results show or mean.

This is how our lesson is gonna look today.

We're gonna start with vibrations and solids, and then we'll go on to talk about how scientists make conclusions and ask questions.

There are sounds all around us.

Actually, as I'm recording this, I can hear rain pattering on the roof where I'm working.

But how are sounds created? Here we can see a guitar string, which vibrates when it's plucked.

And when you shake or you hit or you move some objects, they vibrate.

These vibrations cause sounds to be made.

When I tap on my little drum, for instance, here, (percussive tapping) it's the skin of the drum that's vibrating.

When an object vibrates, it creates sound waves.

And these sound waves need a medium to travel through to reach our ears.

So, what's a medium? Well, a medium can be a solid, a liquid, or a gas.

We can hear sounds, for example, through a closed door, which is a solid.

We can hear them underwater, through a liquid; and we can hear sounds, as well, through a gas, through the air.

Can you think of some other examples? Have a talk with a partner.

I'll ask you to pause the video now and see what you each think.

Compare your ideas.

Right, pause the video now please.

I hope you thought of lots of examples.

I'm sure you did.

Here's a true-or-false for you to think about.

Sound needs a medium to travel through.

Do you think that's true or do you think it's false? And more than that, I'd like you to say why you think this.

You could say, for example, that you think sound needs to travel through a solid, liquid, or a gas.

Or you could say that sound only travels through air, which is a gas.

You need to decide true or false, and then justify your answer, using A or B.

Off you go, have a think now.

And here are your answers.

Sound does need a medium to travel through.

And yes, that can be a solid, a liquid, or a gas medium.

Izzy and Laura been learning about toys from the past.

"In the past," says Izzy, "children played with string phones.

These were cups or cans connected by a string.

If a person talked into one cup, the sound travelled through the string, and the other person further away could hear it in their cup." "I don't understand," says Laura, "how the person could hear the sound on the other end if they're far away." Here's a very simple diagram and a simple drawing to show you the string phone with the cups and the string in between.

But just take a moment to think.

How do you think it works? Just pause the video for a moment and talk to your partner.

Yes, you may have done this before.

I know I have, and had a lot of fun doing it, but it doesn't always work unless you get certain things right.

So, let's have a look.

When a person speaks, vibrations travel through the solid cup or can, through the solid string, to the other solid cup or can.

They reach the other person's ear and cause the eardrum to vibrate, which allows them to hear.

That's how a string telephone works.

Well, of course, Laura and Izzy were very keen to have a go at this, so they made a string telephone, and they tried it out.

Laura speaks quietly into the cup and Izzy listens on her end, but Izzy can't hear Laura.

Why do you think this is? Have a chat with your partner again.

Just pause the video now.

Now their friend Jun is getting involved.

He's done some research to find out what they have to do to make it work.

And Jun says, "My book says that the string attached to the cups needs to be stretched taut.

And this means it needs to be stretched firmly or tightly." "I wonder," thinks Suzie, "if that's something to do with the vibrations travelling through solid mediums." Why do you think that the string needs to be taut? Again, have a chat with the person next to you.

Pause the video now.

Hold on to those ideas, now, because we're going to have a look at some statements.

I'd like you to think, as I read them, which of them you think is the best explanation of the way that vibrations travel through a string telephone.

What you can do to show me when you think I've read out the correct one is to take your hands and wave them in the air like this.

Okay? Here we go.

Is it, A: vibrations travel through electricity, because phones are an electrical appliance? Is it, B: vibrations travel through the solid cups and the solid string to the person's ears? Or is it, C: vibrations travel through the air and cause the person's eardrums to vibrate? And here's your answer: vibrations travel through the solid cups and the solid string to the person's ears.

Well done if you've got that right.

Time now to get practical.

You need some string, some recycled cups, and a pair of scissors.

Can you create a string telephone toy? Try using it.

Try using it with loose string, and try using it with taut or tight string.

And then, when you've done that, see if you can explain how those vibrations can be heard.

Pause the video now.

Well, wasn't that fun? I hope you managed to come up with some questions of your own while you were exploring how your string telephone toy works.

So, can you now explain how the vibrations can be heard? Izzy explains it this way: "When the string was not taut, I couldn't hear what Laura was saying." Laura noticed that, "When the string was taut, the vibrations could be heard travelling through it." Did you get the same results as Izzy and Laura? Did you manage to keep your string perfectly taut, I wonder? And how far apart did you stand? And what sort of tins or cups did you use? Did that make a difference? There are lots of questions that come into our minds when we're doing science.

So, now we're going to turn to think about how scientists make conclusions and ask questions.

Of course, there are many other ways to investigate how vibrations can be heard when travelling through some solids.

Try this, for instance.

Place your hand under a table and scratch it with your fingernail.

Can you hear the vibrations? Now, scratch again, but place your ear on top of the table.

Do the vibrations sound different? I'm just gonna ask you to pause the video so that, if it's possible, you could have a quick go at this.

So, pause the video now.

Great.

Well, Jun says, after trying this, "The results of this investigation show that the vibrations sound louder when my ear is on the table.

But why?" Scientists make conclusions and ask questions.

They use their results to make these simple conclusions.

And a conclusion is when scientists explain what the results show or mean.

So, here's an example.

The sounds are much louder and clearer travelling through the solid table.

In solids, the particles, tiny parts, are packed closely together.

So, when you make a sound, vibrations travel through the solid medium more quickly.

We can hear these sounds louder and more clearly.

And we have a little diagram or simple drawing here to show you the particles in a solid.

Conclusions can often raise further questions for scientists.

Izzy and Laura are young scientists.

They've been thinking about that experiment scratching the tabletop, scratching under the tabletop.

And Izzy's wondering whether maybe, if she put her string telephone toy onto the tabletop, how that would sound.

"Will the vibrations sound louder and clearer through my string telephone toy?" That's what she's wondering.

Well, Laura thinks differently.

Laura says, "I think it would be better to just speak out loud so the vibrations pass through the air.

I think I would be able to hear the person better." Conclusions can often raise further questions for scientists.

Izzy and Laura have been thinking.

They've been thinking about scratching under the table and putting their ear to the table to hear those vibrations.

Izzy thinks, "Well the vibrations also sound louder and clearer through the solid medium of my string telephone toy?" Laura, she thinks that it would be better to just speak out loud so the vibrations pass through the air.

"I think I'd be able to hear the person better," she decides.

What do you think? Might there be a time when you could hear someone better through a string telephone than you could hear them if they were talking to you and the vibrations from their voice was passing through the air? Pause the video and take a moment to have a chat with this with a partner.

Scientists use their results to.

I want you to give me a double thumbs up if you think that what I'm saying is right.

So, scientists use their results to make conclusions; to raise further questions; or to hear vibrations.

You got it.

It was the first two that were the correct answers.

Vibrations travel through a solid medium more quickly.

We can hear these sounds.

Well, which of these do you think it is? Is it quieter and more clearly? Is it louder but less clearly? Or is it louder and more clearly? I'd like you to decide A, B, or C.

I'm gonna ask you now, and I want you to give me a double thumbs up if you think it's A, B, or C.

Yes, the answer's C.

Vibrations travel through a solid medium more quickly.

We can hear these sounds louder and more clearly.

Does the medium the vibrations travel through affect how loud and clear the sounds are," wonders Jun.

So, let's do task B.

Compare speaking quietly to a partner through a gas medium, the air; and through a solid medium, using the string and cups that you made.

Write a conclusion to explain what your results show.

And part two of task B is this: Based on your results, think of another question that you would like to ask and investigate.

I'm gonna leave you to do that right now.

So, pause the video please.

I hope you got on well with that.

Shall we read what Jun concluded? Let's read his conclusion now.

So, he's comparing speaking quietly to a partner through a gas medium, the air; and through a solid medium, string and cups, just like you did.

Here's his conclusion: "When I listened to my partner talking through the string telephone, I could hear the sound really loud and clear.

I think this is because vibrations travel more quickly through a solid medium, which is the cups and the string.

When my partner talked without the string telephone, I could still hear the sounds, but they were not as loud and clear.

I think vibrations travelling through a gas medium, air, do not travel as quickly." Part two was to ask a question, and this is Jun's question, based on his results.

"Does the length of the string affect the sound?" Hmm.

He could try investigating that, couldn't he? "Can I make a string cup telephone for three or more people?" Ooh.

That would be interesting.

And also, Jun asks, "Does the size of the cups matter?" We've got one more speech bubble with a question mark in it, and that's for you to think if you have some great questions to share.

So, I'm gonna ask you to pause the video and just spend a moment sharing your question with the others in your class.

So many good ideas.

Well, time to sum up about vibrations and solid materials.

Sound travels from an object, through a medium, to our ears.

Vibrations can be heard when travelling through some solids, such as taut string and cups.

Scientists use results to make simple conclusions and raise further questions.

Vibrations travel through a solid medium more quickly.

We can hear these sounds louder and more quickly.

Well, we've come to the end of our lesson today, and I just wanted to say well done for your investigating, and well done for coming up with so many interesting thoughts and questions and ideas.

Maybe some of them will lead you to go on and do some further investigations on your own.

Good luck with that!.