Hello, my name is Mr. Wilshire, and in this lesson, we're going to be looking at the function of the heart.

Let's jump in.

The outcome of our lesson is I can describe what the human heart is and what it does.

There are some key words that are going to come up throughout this lesson, so if you need to, you can pause the video now to have a think about what they mean, just to remind yourself of the definitions.

Don't worry, though, because as we go through the lesson, some of the meaning behind them will become clear.

The key words are organ, function, heart, blood, and model.

The first part of our lesson is called all about the heart.

Now, the human body is made up of many different parts.

Here, you can see a cross section of the human body.

If we were to take away the skin and look underneath, this is what it would look like.

You can see all sorts of different bones and different parts inside the body.

Now, all of those things have got a different job to do.

All of them work together to perform all of the different functions of life.

Hmm.

I wonder, what kind of functions of life do we mean? Well, breathing is one of them.

We need to be able to breathe to stay alive.

Eating is another one.

So I wonder what different parts of the body that you can name.

Pause a video now and have a discussion.

Restart when you've done that.

How did you get on? Did you think of any important organs that were in the body? Our lungs are very important.

They help us to inhale air.

What else do we do? Oh, well, the stomach, that also takes in the food and it helps digestion, doesn't it? I wonder what else you mentioned.

Now, one of the most important parts of the human body, it could be argued, is the heart.

Here, you can see a cross section of a boy and a girl, and there's an example of the human heart.

You can see the position of it there as well.

This is the human heart in the body and where it is.

The heart is an organ.

This means it has a particular job.

That also means it could have a function.

That job is very important in the human body.

It's helping to keep us alive.

Now, the walls of the heart are made from muscle.

Here, you can see an example of the heart that someone has drawn, and there is the heart muscle going around the edge.

So it's not a bag of skin, it's actually made up of muscle.

Inside of this, if we were to take the muscle away and have a look inside, we can find lots of different chambers inside.

Now, these are spaces that can fill and empty.

Here you can see two of the chambers of the heart, and they're separated there by a little opening that goes between the top and the bottom.

I can see there's two sides to the heart as well, a blue side and a red side.

Hmm, I wonder why they're different colours.

Let's move on.

Stop and think.

Which the following here is correct? Have a little think, discuss, and restart when you've done that.

What did you think? Is it that the heart is an organ made of muscle, or is the heart only made of blood? Well, actually, there's two answers here.

Yes, the heart is an organ made of muscle, and the spaces in the heart are called chambers.

The heart, as we just found out, isn't just made up of blood.

Its purpose is to pump blood around the body.

So, you've already seen some pictures.

Do you know where the heart is located in your body? Hmm.

Have a discussion with someone.

Whereabouts do you think it is? Restart the video when you've done that.

Whereabouts did you think your heart was, then? Did you say up here? Or maybe you said just here, or maybe you thought it was a little bit to the left of your body.

Well, Jun here, he says, "I think the heart is on the left side of your chest." Hmm.

Izzy says, "I think the heart is located behind the lungs." Well, if I put my hand to my chest, let's see if I can find where my heart is beating.

Have a little go yourself.

What do you think? Who's correct here? Pause the video, discuss, restart when you've done that.

Who is correct? Is it Jun or Izzy? Well, the heart is located in the very centre of your chest.

It's sits between your right and your left lungs, so not quite hidden behind them.

The left lung is slightly smaller to make room for your heart.

Here, you can see an image, and there, you can see a picture of the heart as well.

There are lots of different lines and tubes going up in the air and left and right.

Hopefully we'll find out a little bit more about those as the lesson goes on, but is this where you thought the heart was? Lots of people seem to think that the heart is actually on the left hand side of their body, because that's where they can feel their heart beating.

Now, the heart is located behind and slightly to the left of the breastbone.

That's why we can often feel the heart beating there.

The heart is protected by a frame of bones attached to the breastbone.

This is called the rib cage.

Can you feel your ribs if you were to press around your chest? I wonder if you can feel the ribs up here, or even down below.

Can you feel how it's protecting your heart? The rib cage consists of 24 bones, and this both supports the body and protect the organs.

Of course, yeah, if we didn't have a rib cage, there wouldn't be any rigidity in the top half of our body, would there? Here you can see, on the picture, an example of the rib cage, and the breastbone is the centre part coming right down the middle there.

Let's stop and think.

True or false? The heart is located on top of the breastbone.

That answer is false.

Can we justify this with our scientific thinking? Is it because the heart is located behind the rib cage and the breastbone, or is it because the heart is located behind the stomach and the small intestine? The heart is located behind the rib cage and the breastbone.

I wonder if you know how big a human heart actually is.

Hmm.

Have a quick discussion and decide.

How big is it? If you were to compare the average heart to something else, we would find that it's actually a similar sort of size to a human fist.

If you were to curl your fingers up to make a fist, the average heart is approximately the same size as that.

Take your fist and put it in the centre of your chest.

Does that match up? Is that how big you thought it was? Now, a human heart grows through your childhood, and it stops growing when you stop growing, so your heart, although it may start off very small, is going to grow along with you.

Izzy and Jun here are thinking about the shape of a human heart.

Izzy says, well, "I think the heart looks funny.

It's just like an emoji." Oh yeah, I can see an emoji heart there in the text bubble.

Jun says, "I think the heart is shaped like a drum, because people say that the heart beats." Hmm, they both could be correct, couldn't they? Is the heart like an emoji, and is it a bit like a drum? What do you think? Pause the video here and have a discussion.

Restart when you've done that.

The human heart is almost cone shaped.

Some say it is similar in shape to an upside down pear.

It's quite different to the heart shape that we see in cards.

Here, you can see three pictures.

There's a love heart there, there's an upside down pear, and there is an actual image of the human heart.

Hmm.

I wonder where the love heart came from, then, because it certainly doesn't look like a real human heart, although to be honest, if we were sending a card and it actually had a picture of a human heart on, that wouldn't be very nice or lovely, would it? What do you think? Stop and think.

The heart is approximately this size of your clenched fist.

The answer here is true.

The average heart is approximately the size of a clenched fist.

Let's justify our answers here.

Which of these statements is correct? The answer here is A.

The heart is approximately the size of your fist, and it stops growing when you stop growing.

Which of these diagrams shows the approximate shape of the human heart? The answer here is C.

The first one, A, is a stomach, B is the brain, and C, that's your heart.

This brings us on nicely to the very first task.

The first part of this task is to mould a ball of modelling dough into the same sort of size and shape as a human heart.

You need to explain your choices to a partner.

The second part of this, then, is to place your model in the correct location on an outline of the human body.

Here, you can see a rough outline of the human body.

You may wish to draw your own if you would like to.

So, two sections here.

First, design your heart using some modelling dough.

Second, place it onto an outline of the human body.

Remember, you need to be correct in your placement.

Can you remember where the heart is located? Have a go at this task, and restart the video when you've done that.

Let's find out more, then.

Yours may look similar to this.

Jun here says, "I split the dough into two parts to represent each side of the heart.

My model is the same size as my fist," and it looks a bit like a sort of cone shape.

Izzy has then taken that model and placed it onto an outline of the human body.

She says, "The heart should be placed behind the breastbone, slightly to the left of your chest." You could also use some straws here to represent the rib cage covering up the heart.

That's a good idea.

I wonder how you got on with this creative task.

Were you able to add any other features to the human body? Things that you maybe know before? Let's move on to the second part of our lesson and find out what the heart does.

Jun, Izzy and Jacob here are all talking about the function of the heart.

Jun says, "I think the function of the heart is to make blood." Izzy says, "I think the function of the heart is to clean blood." And Jacob says, "I think the function of the heart is for humans to have feelings." Hmm.

What do you think here? Who is correct? Pause the video, have a discussion, restart when you've done that.

So I wonder who is correct.

Let's find out a bit more.

Now, the function of the heart is to pump blood to different parts of your body.

Here, you can see a moving image of a human heart pumping blood.

Now, the human heart has different chambers, remember.

The blood needs to move into those different chambers, and then it seems to push that blood out of it and then into lots of different areas of the body.

I wonder how it does this.

Humans need blood to be pumped all throughout the body, all through the different parts.

You can see there, there's lots of other different lines going to different areas of the body as well.

The heart relaxes to let blood flow into its hollow chambers.

It then squeezes to push, or pump, blood out to the body.

Here, you can see another moving image of the human heart beating.

Now, each of those beats is pushing blood around the body.

I wonder how many times it would do that within a day.

Now, if you were to squeeze your hand into a fist and then relax, you can see what it's a little bit like for the heart to do all day and all night.

Squeezing and relaxing, squeezing and relaxing.

See if you can squeeze and relax your fist in time with the heart that's there.

I'm getting quite tired already.

The heart is a very special part of the body.

Let's stop and think.

The function of the heart is to clean blood in the body.

The answer here is false.

I wonder if we can justify our answer here.

Which of these statements is true? The answer here is B.

The heart pumps blood to all parts of the body.

Your heart has lots of different valves that open and close.

They allow blood to flow through the heart and then all around your body.

It's a little bit like a one-way traffic system.

Jun says, "The heart controls the flow of blood around the body." Let's take a moment here to listen to the heart beating.

(heartbeat thumping) Could you hear the heart beating? Maybe you understand why people say that the heart beats.

It was a bit of a thumping noise, wasn't it? But that's what's happening inside your chest every single day, all day and all night.

Now, the heart's valve will open up to let blood through, and then it closes again to stop it from going the wrong way.

When different valves inside the heart close, this produces the sound of the heart beating.

You can see here, circled on the image, the different valves that are inside the heart.

If you place your hand on your chest and feel your heart beating, try and see if you can count how many times it beats in one minute.

Well, you're going to need to pause the video here and have a go yourself.

Put your heart on your chest and find your heart, and then count how many times it beats.

Restart the video when you've done that.

How did you get on? Hopefully you were able to keep track of it all that time.

Jacob here says, "Your heart beats an average of 60 to a hundred beats per minute." So your tracking could have been around that sort of range.

This is how we calculate heart rate.

Now, everybody's body is different, so yours could have been a little bit less, maybe it was a little bit more.

It might have been around that sort of number, though.

I wonder if you can use this information to calculate how many times your heart beats in one day.

You're gonna have to think about how many minutes there are in a day, and then multiply that by the amount of beats.

Pause the video, have a go, restart when you've done that.

How did you get on? Have you done your calculations? Let's find out more.

Your heart will beat around 115,000 times each day.

Wow, that's a lot.

I wonder if your calculations were close.

Jun here, "Your heart beats all day, every day, for the whole of your life." It doesn't get tired like other muscles.

Remember, your heart rate can increase when you exercise, so if you are very active and busy, your heart rate is very likely to go up.

Don't worry, though, this is normal.

I wonder if you could have a go doing some exercise, and then see if you can track your heart rate.

There are all sorts of devices that we can get now that can do this for us.

Maybe they're on watches or even on your mobile device, but you could track this yourself just by holding your hand to your chest after you've done some exercise and seeing if your heart rate is different.

Let's stop and think.

Your heart will beat around how many times each day? Your heart beats around 115,000 times each day.

Remember, though, everyone's body is different, so your actual heart rate may be slightly different to this.

Izzy and Jun have learned lots of new information about the human heart, and Izzy says, well, "The heart is a fascinating organ in the human body." Jun says, "How can I explain to my family what that is and how it works like a pump?" Oh, yeah, because the heart isn't an actual pump that you pump up and down, is it? But it does pump blood around the body.

I wonder if you have any ideas.

How could the children show off their knowledge? Have a discussion, and restart when you've done that.

I wonder what your ideas were.

Now, models can be used to help us learn about the function of the human heart.

Here, you can see an image of a plastic model of a human heart.

Izzy says, "Models are often used to help us to understand things that we can't see or experience for ourselves." Well, that's a good point.

Our heart is underneath a lot of skin, bone and other tissue, isn't it? So what models have you used to help explain or understand science? Pause the video and discuss.

Restart when you've done that.

I wonder what models you thought of.

Have you seen a model of a brain before? Or maybe you've seen a model of some teeth when you were learning about brushing your teeth.

Jun is thinking about the function of the heart and how he can make a model to demonstrate this.

He says, "I wonder what I can use to represent the heart and how it works like a pump.

What objects and materials will I need to create my model?" Do you have any ideas? If you were going to make a model that would pump blood, how would you do that? I wonder what ideas you had.

Did you think of a way that you could pump blood? Are you actually going to use real blood? I don't think so.

What could use to represent it instead? Let's pause and think.

Models can be used to help us learn about the something of the human heart.

Models can be used to find out about the function of the human heart.

So this brings us on to our final task of this lesson.

You need to create your very own model to demonstrate how the heart pumps blood around the body.

You could demonstrate the model on the following slide, or you may have some ideas for your own model.

Think about the ways that your model is like a real heart and the ways in which it is different.

You could take a photo or a video of your model in action and then describe what each part represents as well.

Now, this task is completely up to you.

I'm gonna go through some instructions on the other slide, but you might have your own ideas in how you're going to create a working, functioning model of the heart.

Here's some instructions to create a balloon and jar model of the heart.

So the first part here is to fill a jam jar, which is your heart, with water and some red food colouring, which will be the blood.

The second part is to stretch a balloon, which are the muscle walls, over the top of the jar and insert two straws, which are tubes for the blood to flow through.

The third part here is to seal up one of those straws.

That's gonna be one of the valves, isn't it? Then if you push down on the balloon, you're going to be able to pump some of the blood out of the jar.

Now, your model may look like this, or you may have some of your own ideas.

Now, however you choose to make your model of the heart, make sure that you think about how it is different and how it is similar to a real human heart.

Good luck with your task.

See you in a moment.

How did you get on? Your model may be similar to this, or maybe it's a bit different.

Maybe you had your own ideas instead.

You can see here how the straws represent the tubes for the blood to flow through and go around the body.

If you push down on the balloon, it shows that the heart is pumping, and the movement of blood is what keeps us alive.

And Jun here says, "My model is slightly different to a real human heart.

There's only one chamber in my model, whereas a real heart is made up of lots of chambers.

My model has the same amount of blood in the jar, but a real heart fills with blood.

For my model, I have to press down on the balloon skin to pump the blood, but a real heart has a muscle wall, which opens and closes and squeezes blood out of the heart and around the body." So let's summarise our lesson.

The average heart is the size of a human fist.

The heart is a hollow, muscular organ in the centre of your chest.

The function of the heart is to pump blood to all parts of your body.

The heart beats around 115,000 times each day.

And models can be used to help us to learn about the human heart.

Now, whatever you've understood from this lesson, maybe you're going to go off and be a future model maker of hearts or other things in the future.

In that way, you'll be able to help scientists and doctors to improve things, and also check to make sure that other people's organs are functioning properly.

Whatever you get on to do with this experience and knowledge in the future, the best of luck to you.

I've been Mr. Wilshire.

Thank you very much for listening.