Lesson video

Hello everybody.

Welcome back to your science lessons with me, Miss Roberts.

It's so great to see you all again this week.

Oh, you've noticed.

Behind me, it looks very fancy.

It's a room, but it's got lots of different acoustics in it.

Now, the reason that is is because you can see a soft sofa, you can see a hard, flat table and you can see a flat ceiling as well.

Hmm.

I wonder what sort of acoustics this room would have.

What's that, acoustics? Good question.

Lucky that we're here to learn about the amplitude of sound.

I'm going to talk to you all about the amplitude of sound and acoustics during this lesson.

Let's get started.

Okay, so as ever, you need your pencil and a pen, a ruler, and a notebook to write some things down on.

And if you want to, you can get your favourite teddy.

I got Lenny here and he helps me with my science learning.

So pause the video and go and get your resources now.

Okay, let's start with our star words.

The first one is amplitude.

Your turn, amplitude.

Well done.

And I'm doing this because I'm making it very loud because amplitude is all about volume.

So how loud or soft the sound is.

The next word is decibels.

The next word is.

Now, decibels is the unit of measure of amplitude.

But don't worry yet.

We'll get onto that this lesson.

The next word is dB and that is the unit of measure.

That's what we write when we want to write decimals.

Sorry, decibels is not decimals, decibels.

So a small D and a big B.

Let me make that bigger so that you can see it.

There we go, decibels.

The next one is force.

The next one is force.

Well done.

The next one is loud.

Your turn, loud.

The next one is quiet.

Your turn, quiet.

Well done.

We've done our star words.

So now it's time to learn about amplitude.

What's it time to learn about? Amplitude.

Well done.

Oh, sorry Lenny.

His ears were a little bit hurting there.

They were a bit sore because I was shouting so loudly.

We'll hear more about that in today's lesson.

So don't worry, Lenny.

Okay, on the screen, you can see six different sounds.

I would like you to have a look at the different sounds and decide which sound would be the quietest, and which sound would be the loudest sound.

And I want you to write them in order for which ones you think would be the quietest and the loudest.

Let's read them through together.

And then I'd like you to pause the video and decide the quietest and the loudest.

So my turn, your turn.

Aeroplane engine, aeroplane engine.

Child shouting.

Microwave cooking.

My friend whispering, your turn.

My teacher laughing.

And a car horn.

Your turn.

Good job.

Okay.

Pause the video and write down which one you think will be the quietest and which one you think would be the loudest and then order them in between, off you go.

Well done.

Pause the video if you think you need more time.

The quietest sound would be my friends whispering because when we whisper it's very quiet.

The next sound would be the microwave cooking because when a microwave's cooking, what does it sound like? Good, it's quite a quiet sound.

It's like a hum underneath, isn't it? The next sound would be my teacher laughing.

Laughing is a little bit louder than speaking, but not too loud that it hurts my ears.

The next sound would be a child shouting.

That might be something that hurts my ears.

Maybe that's on the playground when they're playing a game or something and they shout really loudly.

If I was stood right next to somebody shouting, it would really hurt my ear.

So you've got to be careful.

The next one would be, the next loudest would be the car horn.

Sometimes when car horns go and I'm not expecting it, they make me jump because it's so loud sometimes.

The loudest sound on the screen is the aeroplane engine.

Because when an aeroplane takes off, it's got a huge engine and lots and lots of power going into that engine, which means it's very, very loud.

Right, so let's think about what all this means and what amplitude actually is then.

When you have a loud sound, it means that it has a high amplitude, it has a high amplitude.

When you have a quiet sound, you have a low amplitude.

You have a? Can you whisper it? Well done.

I could barely hear you.

Okay, so when a sound is very loud, I'm going to do a loud clap now, are you ready? One, two, three.

Good.

Can you do that one with me? We're going to do a loud clap on three, one, two, three.

Good job.

Now that sound is a loud sound and it has a high amplitude.

And the amplitude is the size of the wave.

And so we were doing our waves last week for frequency.

If it's a high amplitude, it's a very big wave.

So, can you show me the wave for my loud clap? So very low and very high doing your wave pattern.

Good job.

So let's do one loud clap again.

Let's make a high amplitude one, two, three, good job.

And that is measured in decibels.

It's measured in? Well done.

And we learned about the star word decibels at the start of the lesson.

So, then a quiet sound has a low amplitude.

So the wave is a very small, can you give me a very small wave? Not like this, you silly sausage.

A small wave like this.

So it's not going really high and low.

It's just staying very, very small.

Let's do a quiet clap on three.

So lets have a low amplitude.

Are you ready? One, two, three.

Oh, I heard some of you very loud.

Let's try that again.

A little bit quieter.

How quiet can you make your clap? One, two, three.

Good job.

And that has a low amplitude, which means it would have a very low number on it.

What do we measure amplitude in? What's the unit? Deci, decibels, well done.

Okay, so if it has a high amplitude it's a loud sound.

If it has a low amplitude, it's a quiet sound.

The reason that it is, now this is very important scientists, when you apply a large force it means that you are making the vibrations even greater.

So when we make a big clap, I have to really put a lot of effort in if I want to make it very, very loud.

So if I wanted to make it even louder, let's make a really loud clap now and really think about the force we're putting in.

So you're losing energy, sorry, you're using energy in your arms. Ready? Get your hands ready.

One, two, loud, go! Well done.

I have to make my arm really wide and I have to apply a large force.

I have to apply a large force.

Well done.

If I'm making a quiet sound I don't have a very large force.

In fact, I have a very small force.

When I'm clapping, I'm not putting much energy into that and I don't need to move very far.

So that's a low force creating a quiet sound with low amplitude.

Okay, so that's what we need to know about amplitude.

What's it measured in again? Deci, can you tell your screen? Decibels.

Well done.

Great job team.

I'm going to give you an awesome cheer because you've listened to that really, really well.

So, decibels, as I said before, is often abbreviated to D with a capital B.

It's important it's that way around.

What was our frequency measured in last week? Hm, there was a German scientist named Her.

I'll give you a clue.

If I pinch, ow! Hertz, well done.

But not hurts like I hurt myself.

H-E-R-T zed was our frequency.

So this is similar to that.

But decibels is the measurement of amplitude.

Can you say decibels? Your turn.

Can you say it loud? Decibels.

Your turn.

Oh, that was loud.

And can you whisper it? Decibels.

Pardon? You were so quiet.

I couldn't even hear you.

Good job team.

What I'd like you to do is pause the video and see if you can finish these sentences.

Pause the video now and write your answers in your notebook.

Well done, everybody.

If you need more time, you can pause the video or if you're not sure, you can't remember, that's okay.

You need to go back to the start of the video and watch the information again.

If you've forgotten some of the words that you need.

So let's have a look at the answers and see if you are correct.

The louder the sound, the higher the amplitude.

Remember, there was a big wave.

To make a loud sound you need more force.

Remember our big clap.

A whisper has a sound with a low amplitude because it's a soft, quiet sound.

What is the unit of measure of amplitude? Well, I'm sure you all got that one right.

It's decibels.

Give yourself a tick for those or edit your answers if you got one of them wrong.

So, now 15 decibels.

Decibels are the measure of what? Amplitude, well done.

So 15 decibels is a very low amplitude.

15 decibels would be how loud it would be if I was whispering, so it's not very loud.

Can you whisper? Can you say 15 decibels? Well done.

30 decibels would be my speaking voice.

So if you're speaking, you're probably around 30 decibels.

That's the measurement of how loud your sound is.

So can you say 30 decibels at a normal talking voice? Well done.

So the volume of your voice right then was about 30 decibels.

If you get to 90 decibels, that's very, very loud.

You're probably shouting.

I'm not going to make you shout because otherwise people get a little bit worried, but if you were shouting it would be 90 decibels.

Or something very, very loud like a loud lawn mower or a very loud engine of some sort.

If you get up to 150 decibels, I know team, gosh, that does sound loud.

That's a sound so loud that it would hurt and possibly even damage, in fact, probably damage your ears.

You would not feel very comfortable listening to a sound.

It would really, really, really hurt.

And it may even burst your eardrum because it's too loud.

So if a sound is too loud, it can damage your ears.

And that can be really dangerous.

For example, when you go on an aeroplane and there is somebody who helps guide the aeroplane forwards and backwards, because aeroplanes are so big.

You may have seen them, or you may have also seen them on TV.

If you've seen those people, can you have a think? What did they wear on that ears? Well done.

Now, in order to protect their ears, they wear headphones.

And this protects their ears.

So the sound cannot get into their ears because the sound of the engine is so loud.

Now these are my ones for playing music, they're not very protective, But you can get ear phones that are made or sorry, headphones that are made to be very protective of your ears.

So that sounds cannot get into your ears.

What I'd like you to do now is just cover up your ears with your hands.

And I'd like you to see if the sound in your, in wherever you are, in your room or in your school is different.

Hm, and take your hands away.

Good.

I can't hear as much as I can do when I've got my ears, like my hands over my ears, because it stops the sound getting in.

Okay, so now let's play another game of higher or lower, but this time we're going to think about decibels.

So, is this a quiet sound with low amplitude or a loud sound with a large amplitude? Can you say higher or lower? Your turn.

Well done.

It's low.

That's a low sound with a large or a small amplitude? Good, a small amplitude.

Next one, 200 decibels, higher or lower? Higher, well done.

What was the number of decibels that would damage your ears? Can you tell me? Good, 150.

So 200 decibels would almost be, you could almost kill someone with a sound that loud if they're really close to it.

You'd have to be really, really, really careful.

Well done, so that has a high amplitude.

96 decibels, is that loud or quiet? Higher or lower? Tell your screen.

Well done.

That is a high amplitude.

So it's a loud sound.

96 decibels will be if you're shouting really, really loudly and you were right next to the sound.

12 decibels, high or low amplitude? Tell your screen.

Well done.

That's a low amplitude.

That would be quite a quiet sound.

Okay, so now I'm going to show you some images of a scale.

Now we're going to start at the loudest sound and we're going to go right down to the quieter sounds.

Now this is an image from Shutterstock, and it's a really important way to think about how loud sounds really are.

Now, I know I talked about 150 and even 200 decibels being extremely damaging.

Sounds that loud would be extremely damaging for the human ear and even the human body.

So you've got to be very careful.

So the loudest sound on the scale is 140 decibels, and that would be if you were next to a firework.

Obviously when we watch fireworks displays, it hurts our ears a little bit, but it doesn't break our eardrums. If we were right next to the firework where the sound is loudest, that would break our ears and you would not be able to hear anymore.

The sound, the volume, sorry, of a jet engine of an aeroplane would be 130 decibels.

That is extremely loud.

So you can see a police siren, a trombone or a helicopter are also extremely loud sounds.

So now going down the scale a little bit, you've got a hairdryer, a truck and a car.

Those sounds are 70 to 90 decibels and they are still very loud.

You know, if somebody's drying their hair, you can't hear what they're saying can you? Because it's so loud that you can't hear anything else on top of it.

Everybody has to wait until somebody's finished drying their hair.

Or if a truck goes past, you might have to say, "Pardon?" If someone says something, I wouldn't be able to hear it.

Now, like we said, a conversation, rainfall on the window, or even a refrigerator would be a moderately quiet or even faint sound.

So they're quieter sounds.

And a whisper, rustling of leaves or breathing are very quiet sounds.

So, which sounds that we've just looked at on this scale have the bigger force? Was it the breathing and the whispering? Or would it have been the fireworks and the jet engine? Which of those sounds has the bigger force? Can you tell your screen? Well done.

The fireworks has the biggest force because it's the loudest.

Well, it's the loudest because it has the bigger force I should say.

So when we looked at our clap and we have a very loud clap, we're putting a lot of force into it.

And you can think can't you, that a big jet engine or a big explosion of a firework has lots of energy compared to breathing or rustling leaves, which are gentle and quiet.

Well done team.

If something has no decibels, then it's silent.

You won't be able to hear it.

Okay, so now we thought about the amplitude and we've looked at different scales of how loud things are.

Let's think about if there's a really loud sound, what can we do to protect our ears? Now, protecting our ears is really, really important.

We looked at soundwaves entering the ear canal, touching the eardrum, sorry, vibrating the drum, and then vibrating the bones inside the ear.

That then sends that signal up to your brain, doesn't it? And we looked at that together.

However, if there's a very loud sound, it's going to be really damaging for our ears.

So what can we do to protect our ears? I wonder, can you tell your screen? What's one way that I've already told you about protecting your ears? Good job.

Well done team.

So often, if you are in a very noisy place, such as near aeroplanes , or if you operate heavy machinery that's very, very noisy, you'll have to wear headphones.

Sometimes you can also wear ear plugs.

Now I've got some earplugs here.

They don't look the kind of ear plugs that you might expect.

Sometimes you see bright orange ones.

These are squishy ones.

Can you see? Got to hold it here.

Let's do this.

So, this earplug here is a special one and you can use them when you're swimming, if you want to.

But they also are very, very good for protecting your ears from sound.

So I can put them in my ear and I can't hear anything because oops, because it's stopping the waves from entering my ear.

So it's very, very protective of my ear.

So, I wonder what other ways do you think you could protect your ears? Can you think of any other way? Good.

You could stand further away from the sound.

So if you stand further away, the sound is quieter and that will also help to protect your ears.

Now, when I studied music at university, I remember one of my first ever lectures there.

And they used to tell us about listening to loud music.

So if you listen to loud music on your headphones, like we looked at last week, or with earphones, if you have that up too loud, you can get a ringing in your ear.

And that means that you've damaged a little, little, tiny part of your ear.

If you damage your ear, you cannot repair it again.

So it's really important you take really good care of your ears and don't listen to loud music in your headphones too loud, or go and listen to live music too loud, or are near loud sounds for a long amount of time.

So you've got to be really careful.

You need to protect your ears with the headphones, earphones or moving yourself away from the sound.

Okay.

It's time for your learning review.

In the end of this lesson, I'd like to have a look at the worksheet and have a go at the questions in your learning review.

Well done everybody.

Good job team.

Been really impressed with your learning today, and I've really enjoyed our lesson.

Next week, I'll be back with more science.

Bye everybody.