Hello, my name is Mrs. Mehrin and I'm so excited to be learning with you today.

Today we are going to be learning all about changing the pitch of sounds.

Let's begin.

Welcome to today's lesson from the unit, introduction to sound.

Your learning outcome today is I can find patterns between the pitch of a sound and the length of the vibrating object.

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 are going to learn lots of fabulous new things.

Here are your five keywords along with the definition.

Now your keywords are in bold.

I am going to be referring to these keywords and definitions throughout today's video.

Now if it helps you, you can jot these down, but that's not necessary.

If you would like to, you can pause the video here and have a go at jotting those down now.

Fantastic, well done.

So today's lesson is split into two parts.

Let's begin with the first part, measuring pitch.

Now pitch describes how high or low a sound is.

Can you identify the sounds as high or low pitch? So we've got a drum, thunderstorm or a mouse squeaking.

So I'll give you five seconds now to have a think about your answer.

Off you go.

Fantastic, well done.

So a drum and thunderstorm often make low pitched sounds and a mouse squeaking often has a high pitched sound.

Now, Andeep and Izzy are comparing pitch.

Andeep says, "my dad has a really deep voice when he talks.

I think he has a lower pitched voice than your dad." And Izzy says, "I disagree.

I think the pitch of my dad's voice is lower than your dad's voice when they both talk." Now, how could Andeep and Izzy compare the pitch of sounds? What could they do? I'll give you five seconds for you to have a think about your answer.

Off you go.

Fabulous, well done.

So some sound sensors can be used to detect and measure pitch.

So Andeep says, "I thought sound sensors measure the volume of sounds.

The sensor inside my data logger does not measure pitch." And Izzy says, "well, some sound sensors are able to measure the number of vibrations travelling in sound waves in one second.

This is a measure of pitch." Now let's do a quick check-in of your learning.

True or false, pitch describes how loud or quiet a sound is.

Is that true or false? I'll give you five seconds to think about your answer.

Off you go.

Fabulous, well done, the answer is false.

Now let's see if you can justify your answer.

Is it because A, pitch describes how low or high a sound is? Or B, pitch describes the distance you are away from a sound? Again, I'll give you five seconds to think about your answer.

Off you go.

Fabulous, well done.

The answer is A.

Now how can pitch be measured? Is it A, using a microscope, B, using a sound insulator, or C, using a sound sensor? Again, I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

The answer is C, using a sound sensor.

Now the unit for measuring pitch is hertz, and this is sometimes written as Hz for short.

A high pitched sound is made when an object is vibrating more quickly so that there are more vibrations per second.

So a birdsong is a high pitched sound and can reach up to 8,000 hertz.

So here we have a brown creeper song, which is very high pitched.

Now a low pitched sound is made when an object is vibrating more slowly so that there are less vibrations per second.

So the pitch of the lowest note on a grand piano is 27.

5 hertz.

Now Andeep and Izzy ask their dads to read out the same sentence from a piece of paper.

They download a sound sense app onto Andeep's tablet so they can measure the pitch of each voice.

Andeep says, "the pitch of my dad's voice is 85 hertz" and Izzy says, "the pitch of my dad's voice is 102 hertz." So what do their results show? I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

So as we can see, Andeep's dad has got a lower pitched voice than Izzy's dad does.

Now let's have a look at this question here it says, "what unit is used for measuring pitch?" Is it A, lux, B, decibels or C, hertz? I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

The answer is hertz.

Now what you are going to be doing is using a sound metre app to measure the pitch of some everyday sounds.

So I want you to try predicting the pitch first and then comparing how close you were.

So you're going to do a low male voice, talking to a friend, children laughing, phone ringing.

So I want you to predict what you think the pitch will be in hertz first, and then I want you to measure it.

Okay, I'm going to give you some time now.

So I'd like you to pause the video here and have a go at this activity.

Off you go.

Fantastic, well done.

So as we can see here, we've got when they measured a low male voice, it was 100, talking to a friend they predicted was 200, but it came out as 350 hertz.

Children laughing they thought would be 500 hertz, but it actually came out as 1,500 hertz and the phone ringing they thought would be 650 hertz, but it came out as 450 hertz.

So a male voice can actually go anywhere between 85 hertz and 180 hertz.

Children talking can be anywhere between 250 to 400 hertz.

Now I know that the children laughing came up as 1,500 hertz.

However, if it was females laughing, they can actually sometimes go all the way up to 2,000 hertz and the average ringing tone is between 400 to 450 hertz.

Now we are onto the second part of our learning today, which is changing pitch.

So Andeep and Izzy try making sounds by blowing across the top of a wide paper straw.

They make a buzzing sound as the straw and air blown over the straw is vibrating.

Andeep says "the sound of my paper straw is a different pitch to yours." And Izzy says, "I wonder why that has happened.

We should measure the pitch of sounds to compare." So the children use a sound metre to measure the pitch of the sounds made by their paper straws.

Andeep says, "the pitch of my straw is 440 hertz" and Izzy says, "the pitch of my straw is 490 hertz." Now why do you think their results might be different? I'll give you five seconds to think about your answer.

Off you go.

Fabulous, well done.

So Andeep and Izzy compare the length of their paper straws.

Now what do you observe about these paper straws? I'll give you five seconds to think about your answer.

Fantastic, well done.

So Izzy says, "my paper straw is shorter than yours.

So I wonder if that could affect the pitch." What do you think? Do you think Izzy's straw being shorter can affect the pitch? I'll give you five seconds to think about your answer.

Off you go.

Fabulous, well done.

So then they try other length paper straws and measure the pitch of sounds produced and they record their results in a table and look for patterns in their data.

Now, Andeep says, "I think the length of the straw affects the pitch of the sound." Now scientists look for patterns in sets of results to tell them how one thing can affect another.

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

Scientists look for patterns in results to tell them, A, why they did the experiment.

B, what equipment they needed to use, or C, how one thing might affect another.

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

Off you go.

Fantastic, well done.

The answer is C.

Now here are Andeep and Izzy's results.

Can you identify any patterns in these results? I'll give you five seconds to think about your answer, but if you need longer, you can pause the video here.

Off you go.

Fabulous, well done.

So Izzy says, "my results show that the pitch got higher as the straw became shorter." Do you agree with Izzy? I'll give you five seconds to think about your answer.

Off you go.

Fabulous, well done.

So changing the length of the vibrating object can affect the pitch of the sound it produces.

So Andeep says, "the longer the paper straw, the lower the sound it made." And Izzy said, "so you can change the pitch on an object vibrating by changing its length." Now let's see what Laura and Lucas have to say.

Laura says, "different length straws will produce different pitch sounds" and Lucas says, "different length straws will produce the same pitch sounds." I'll give you five seconds to think about who you agree with and why.

Off you go.

Fabulous, well done.

So it's Laura who is correct.

Izzy finds a musical instrument called a pan flute made by fastening different length pipes together.

What will happen to the pitch of the sound when she blows across the top of the pipes from longest to shortest? And why do you think this will happen? So I'd like you to pause the video here and have a go at this activity.

Off you go.

Fantastic, well done.

So the pitch of the sound will start lowest at the longest pipe and then become higher in pitch as the pipes become shorter.

Now this is because the longer the object vibrating, the lower the pitch of the sound.

So here is task two.

It says, "make your own paper straw pan flute by fastening different lengths of straw together with sticky tape." So you need to measure the straws, then carefully cut the straws, then fasten the straws together with a strip of sticky tape.

So I'd like you to pause the video now and have a go at this activity.

Off you go.

Fantastic, well done.

So now you are going to explain how changing the length of the vibrating object affects the pitch of the sound it produces.

So I'd like you to pause the video here and have a go at that activity.

Off you go.

Fantastic, well done.

So it says here, "I observed that changing the length of the vibrating object affects the pitch of the sound.

Longer straws vibrate to produce lower pitched sounds and shorter straws vibrate to produce higher pitched sounds" So now we are onto the summary of your learning for today.

Pitch describes how low or high a sound is and can be measured using a sound metre to detect pitch.

The unit for measuring pitch is hertz.

Scientists look for patterns in sets of results to tell them how one thing affects another.

Changing the length of the vibrating object can affect the pitch of the sound it produces.

Fantastic work today.

Well done.

I am so proud of you and you have worked really, really hard and you have learned lots about changing the pitch of sounds.

Well done.