Lesson video

Hello, everybody.

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

So we are carrying on with our sound unit.

Today, we're looking at frequency and pitch.

I have Lenny the lion here as Evan next to my screen so that I can tell him all of my star words, and he can listen to all of my learning.

So if you want to go and get your favourite Teddy and put them by your screen to help you, go and get them now.

Okay, you will need a pencil and pen.

You will need a ruler, a notebook, and you may want some colouring pencils today, but you won't need them if you've not got them.

So don't panic.

Pause the video and go and get the resources you need now.

Okay.

I think we are ready to get started.

Let's start with our star words.

Ready? Star words, star words, star words.

Well done.

The first one is what we had last week, which is pitch.

Remember we had pitch, so we had high and then low, because you can have high and low pitch.

So my turn your turn.

Pitch.

Your turn.

Well done.

Frequency.

Your turn.

Let's do that one again.

Frequency.

Your turn.

And you'll notice I'm doing a wave with my hand because frequency is the frequency of a wave of a sound wave.

So, we'll see that more in today's lesson.

So just one more time.

Frequency.

Your turn.

Well done.

Vibration.

Your turn.

Good job team.

And Hertz.

Your turn.

Now this is not hurts like if you pinch something it hurts, ouch, this is Hertz.

You'll notice it has a capital h.

And what do we know if a word has a capital letter at the start? It means it must be a proper noun.

Well done.

And in this case, Hertz is somebody's name.

It was a German inventor who discovered the Hertz of a sound wave, and then he named it after his surname.

So, I'll explain more about that later in the lesson.

So Martin, your turn, Hertz.

Well done.

It's what we measure the frequency of sound in.

And last two, are nice and simple.

High.

Your turn.

Can you go, high? Your turn.

And low.

Your turn.

Low.

And that's to do with high and low pitch.

Okay.

Now we are ready for our learning.

So, let's think about the frequency of sound.

Now on the screen, you can see a little mouse, and a mouse can hear very high frequencies, and high frequencies mean that he can hear high pitches.

These are very, very high notes.

And so you might think of it a little bit squeaky.

And so a high pitch is the same as a high frequency.

The reason it's a high frequency is because the waves have very frequent.

So the vibrations are happening very, very frequently.

So it's a very fast vibration, which creates a high pitch.

Now you can see a mooing cow and when a cow moos, it's a very low pitch.

Can you say, low, like for our star words, low? Your turn.

Low.

Can you do that even lower? Low.

Your turn.

Well done.

And when you have a low pitch, it means that the frequency is even slower.

So I don't mean slower in speed, what I mean is it's the sound wave is less frequent.

So whereas we had a very fast frequency, a high frequency for high pitch, we have a low frequency for low pitch and the sound wave is occurring less frequently.

We will talk about this more during the lesson.

So don't worry if you're not exactly sure right now.

But what we need to remember is high frequency means a high pitch, and low frequency means a low pitch.

So repeat after me, high frequency means high pitch, and low frequency means low pitch.

Well done.

Okay.

Let's do some breathing to further explore what we mean.

I'm going to make it bigger for you so you can view it on the screen.

Read with me, one, two, three.

How high or low pitched a sound is, is known as frequency.

That's one of our star words.

To make a high pitch sound, you have to have a very fast vibration.

Oh! That's one of our star words.

Well done.

I can see lots of you putting your hands on your head for your star words, just like we always do.

Let's keep reading.

The smaller the object, the easier it often is to create a fast vibration that makes a high pitch to sound.

This is partly why small objects may make a higher pitch sound, like a mouse.

Higher pitch sounds have a higher frequency.

Low pitched sounds have slower vibrations, which means they have a lower frequency.

And frequency is measured in Hertz after a famous German scientist.

Well done.

Those of you who spotted the star word, Hertz, after the German scientist.

So that's what we call, Sorry, that's what we name, frequency.

It is the unit.

It is the? Unit of frequency.

Well done.

I wonder what other units do you know? Can you tell your screen another unit that you know? What about the unit of weight? Well done.

Some of you may have said grammes or kilogrammes.

What about a unit of distance? Well done.

Either miles or kilometres.

So, frequency is the unit that we measure the frequency of sound.

So, as you can see on the screen, it says 20 Hertz.

Can you say 20 Hertz? Well done.

And that is a very low frequency.

So it would be have very slow vibrations.

Now with your finger, just like I'm doing, can you make a very low and slow? So I don't mean a low, I just mean a slow, wave pattern with your finger like this.

So I'm go up and down and up and down.

And I'm not going up and down really fast.

I'm making it really slow, so they're quite wide.

Can you do that with me? Ready, steady, go.

Up and down, and up and down, and up.

So they're very spread apart.

If I went really fast like this, they'll be very close together.

Let's do it one more time, a low frequency.

Ready, steady, go.

Up and down, and up and down, and up.

Well done.

Let's have a look at the next one.

So, on this screen, I've showed you, I've shown you, sorry, not showed you.

That's very poor English of me.

Now, it says 20 Hertz to 20,000 Hertz.

Hmm.

I wonder what you think this is the range of.

So something between 20 and 20,000 Hertz.

What do you think that is the range of? Can you have an educated guess? Can you make an S.

Hmm.

Well done.

It's what humans can hear.

So humans tend to be able to hear frequencies between 20 and 20,000.

Now, sometimes if people can't hear very well, then the low and the high frequencies will be harder for them to hear.

So they will hear a smaller range.

So sometimes my dad goes, "pardon?", and I know that maybe I've spoken too loud or too high in pitch so that he can't hear it as well.

I wonder who else, you know, that has a little bit of trouble with hearing high pitches.

So, let's have a think.

We've thought about the frequency of sound.

Let's play a game now, called higher or lower.

And this game, those are this higher or lower.

Can you do that with me? One, two, three, higher or lower.

Well done.

Okay.

So, I'm going to show you a frequency on the screen and I want you to think, and then tell me if it's high or low.

Okay? So, let's do the first one together and then I'm not going to help you.

60 Hertz.

Is that high or low frequency? Let's think.

Tell your screen, what do you think? Low frequency.

Well done.

That is a low frequency.

Okay.

Now it's over to you.

I'm not going to help you.

Read it on the screen.

10,000 Hertz, well done.

Now think, high or low? Tell your screen.

Well done.

That's a high frequency.

That will be a very high pitch.

Next one.

Read it on the screen.

Well done.

15,000 Hertz.

Would that be a high or low frequency? Tell your screen.

Well done.

That would be a high frequency.

So high pitch.

Good job team.

Next one.

Read it on the screen.

85 Hertz.

Is that high or low? Think.

Now tell your screen.

Well done.

That's a low frequency.

So that would be very slow vibrations.

So, now on the screen, you can see, I have drawn a diagram of the wave pattern for high frequency sound.

As you can see, there are lots and lots of waves, very close together.

And this is the representation of the vibrations and the frequency in which they occur.

So you can see they're close together and they're happening very regularly.

So they're happening quickly, which means it's a high frequency.

If you compare this to the low frequency wave, you can see that there aren't anywhere near as many waves in this one.

How many ways can you count? I can count one, two.

That's not very many.

If this was over a minute, this would be only maybe like we had before, 85 Hertz.

Whereas if we go back to the high frequency, how many ways can you count? I make even bigger for you.

One, two, three, four, five, six, seven, eight, nine, 10, 11.

I counted 11 waves on that one.

So if we have 11 waves and if we have that spaced over a minute, that would be a high frequency, may be something like over 10,000 Hertz.

And that would be why it's a high frequency.

Now just to be even clearer with this, I've brought my violin along.

And with my violin, I'm going to play you a high pitched note, that has a high frequency.

This means the vibrations are happening very, very quickly and very close together.

So I'm going to put my finger right up, oh, then just go this way, on the top string right to the very top, it's going to be very squeaky.

That's a very high pitch note.

I'll give you another one.

I'll give you one more.

It's very squeaky, isn't it? So the vibrations of those, of this note that I'm playing, the wave pattern is like the one you can see on the screen, the waves, the vibrations, are happening very, very quickly and close together.

So they're very frequent.

If I then have my low frequency, and the vibrations are slower, I'm going to play you a low note.

I'm going to play you another one.

I'm going to play you one more.

Good.

So my low frequency notes, on my violin, have a wave pattern similar to the one you can see on the screen.

What I'd now like you to do team, is to draw the wave patterns like I have.

I want you to draw the high frequency and I want you to draw the pattern of a low frequency sound.

So pause the video on the wave pattern that you need, and draw them in your notebook.

Okay.

Well done everybody.

Oh let me just get the right screen.

There we go.

I hope you enjoyed drawing those.

And I hope you made them as even as you can, because the wave patterns are evenly spaced, just like how I drew.

Okay.

So just to finish off, we're going to think about what animals can hear.

On the screen, you can see a table, and my column headings are animal, low frequency and high frequency.

So in this table, we're thinking about the frequencies the animals can hear.

So the lowest ones they can hear, and the highest ones they can hear.

Just like I showed you with the human frequencies.

What were those again? 20 Hertz to? What was the high frequency that humans can't hear? 20,000 Hertz.

Well done.

So, let's read for the mouse.

So a mouse, what's the mouse's low frequency, that it can hear? 1000.

Well done.

And what's the high frequency that a mouse can hear? Tell your screen.

Well done.

Now an elephant, what's the low frequency that an elephant can hear? Good job.

And the high frequency? Well done.

I heard some of you say 12,000.

Now, I want you to say 12,000 Hertz, because that's the unit of frequency.

So what's the high frequency that an elephant can hear? Well done.

12,000 Hertz.

And finally for a dog.

I want you to read on the table, the low and the high frequencies.

Tell your screen now.

Good job.

50 Hertz to 50,000 Hertz.

Now, what's I'd like you to do, is that I'm going to set you a quick challenge and I want you to draw this table in your book.

But, I do want you to draw it out like it is.

I want you to order the table differently.

So the animal at the top in the first row, is the smallest animal, and the animal on the bottom row is the largest animal.

So you've got mouse, elephant and dog, which is the smallest? Tell you screen.

Good.

Which is the largest? Good.

So which one would be in the middle? Well done.

I'm not telling you the answers on purpose because I want you to now have a go, at ordering them, and then we can see if we can find some patterns in the frequencies that they can hear.

So, redraw the table, ordering your animals from smallest to largest, and then write out the frequencies next to those as well.

Off you go.

Well done.

I'm going to give you an awesome cheer, because you guys are working so hard today.

I'm really impressed.

Pause the video, if you need more time to finish that table.

Okay.

And here are your answers.

So we realised that the smallest animal was a mouse.

Now a mouse can hear 1000 frequency, sorry, 1000 Hertz for its lowest frequency.

And it can hear 100,000 100, 000 Hertz for its highest frequency.

Then a dog can hear 50 to 50,000 Hertz, and an elephant can hear 16 to 12,000 Hertz.

Now I wonder, can you spot any patterns in this table? I want you to pause the video, and see what patterns you can spot.

Have a look at the frequencies and whether there is anything that you can see that looks like it might be a pattern.

Pause the video and have it go now.

Well done.

I wonder if you spotted any patterns.

I can see that a mouse can hear a range from 1000 to 100,000.

So it's low frequency is 1000.

Now an elephant's is 16 Hertz.

So an elephant can hear much lower frequencies.

So, and then a dog, can hear 50.

So I can see that the pattern is the larger the animal, the lower the frequency it can hear.

Can you just tell your screen, What is the pattern there? The lower, sorry, the larger the animal, the lower the frequency, well done, that it can hear.

So now use that to help you.

What about the high frequencies? Tell your screen.

What pattern can you see there? Mm-hmm, well done.

Good.

So, if it's a small animal, it can hear a higher frequency, because I can see that 12,000, 50,000, 100,000.

As the animal gets smaller, the high frequency gets bigger.

So smaller animals can hear higher frequencies.

Well done.

We spotted some really excellent patterns in that table.

Good job team.

What I'd like you to do now, is write that out in your own words, because when we're scientists, we need to make sure that we can write down our findings.

And now that we've ordered that table, we can write out the patterns that we spotted.

My sentence starter for you is, "In the table, we can see that.

." because we want to be real experts at spotting patterns.

And so we need to use the right words to introduce our findings.

I want you to pause the video and write out your findings now.

If you want to go back and use the table, you can do so, or you can use your sentence starter.

Off you go.

Well done everybody.

I hope you've had a really good go of writing out a pattern.

If you want an extra challenge, you could pause the video and write out your other pattern that you could see, or even you could write down three.

I'd be really impressed, if some of you could find a third pattern, that we haven't spotted together.

That'll be a really independent thing to do.

So well done.

If you're going to have a go, pause the video now.

Okay.

So we thought about the frequency of sound.

We played our game higher or lower, and we've thought about what frequencies animals can hear.

Just before I let you do your learning quiz, what are the frequencies that humans can hear? What was the range? What was the low frequency that humans can hear? Well done.

20 Hertz up to? 20,000 Hertz.

Well done.

And Hertz is a unit of measure of what? Hertz is the unit measure of what? Hmm, thinking? Frequency.

Well done.

Team, I'm so impressed with your learning this week.

Well done.

I'm going to give you another awesome cheer, because you guys have worked really, really hard today.

So well done.

Now it's time to go and do your learning review.

If you would also like to share your work on Twitter, I would love to be able to see it, but please ask your parents or carers, to share it, so that they can help you be nice and safe.

You can tag the hashtags on the screen, so that I can see it.

Good job everybody.

Well done.

And I will see you next time and we'll continue our work on sound.

Bye everybody.