Hello, my name is Mrs. Merin and I am so excited to be learning all about light, entering our eyes with you today.

We are going to do brilliantly.

Welcome to today's lesson from the unit: light and how it travels.

Your lesson outcome today is I can explain that we see things when light travels into the eye.

Now, we are going to be building on some of our previous learning all about how light travels.

Now, I know that learning can be a little bit challenging sometimes but that's okay because it means we're going to learn lots of new things and we are going to have a fantastic time doing.

So let's begin.

Here are your key words for today.

Now, you don't need to worry about writing these down because I'm going to refer to them throughout today's lesson.

However, if it does help you and you would like to write them down, you can pause the video here and jot them down.

Off you go.

Fantastic.

Well done.

And here are the definitions for those keywords.

Again, you don't need to pause the video here, but if you'd like to, you can jot them down if it does help you.

Again, I'll give you some time to do that now.

Off you go.

Fantastic.

Well done.

So our lesson today is fit into two sections.

Let's begin with the first one, how light enters our eyes.

Alex and Laura are discussing how we see things.

Alex says, I know that we need light to be able to see.

I think the light comes out of our eyes so that we can see things.

And Laura says, I think we need light from light source so that our eyes can send out light ray to see things.

What do you think? I'll give you five seconds to think about your answer, but if you need longer, that's absolutely fine.

Just pause the video here and come back when you are ready.

Off you go.

Fantastic.

Well done.

So we need light to see things.

However, Alex and Laura are both incorrect about what happens.

Jun helps Alex to understand that light doesn't come out of our eyes.

Jun says, if light came out of our eyes, then we would be able to see things in a dark room.

When I went caving and turned my torch off, I could not see anything.

Now, remember when we talk about dark room, we mean one that is completely void of light.

So there can't any light at all coming in from outside.

Otherwise you may be able to still see things even if the room appears to be dark.

So what Jun means here is a place where it's completely dark.

There is absolutely no light coming from anywhere.

Now, let's have a look at what Alex and Sam say.

And I want you to think about which person is correct.

So Alex says, "We need light to see things." And Sam says, "We don't need light to see things because light comes out of our eyes." So I'll give you five seconds to think about who is correct here.

Now, if you need longer, that's absolutely fine.

You can pause the video here and then you can come back when you are ready.

Off you go.

Fantastic.

Well done.

So Alex is correct here.

We do need light to see things and light does not come out of our eyes.

Now, Jun is helping Laura to understand that our eyes do not produce light.

So remember Laura said, "I think we need light from light sources so that our eyes can send out light rays to see things." And June says, " We do need light from light sources but light travels into our eyes, it's not our eyes that send out the light.

We see things when light enters our eyes.

And Alex says, "How does light get into my eyes? It sounds very dangerous.

And Jun says, "Remember that light travels out from a light source in all directions.

So when light reaches you, it enters the eye through a special part called the pupil.

It's not usually dangerous unless the light source is very bright." So the pupil of the eye is an opening that allows light to enter the eye.

So here, we have the pupil, which is the black part of the eye, and then we have the iris.

Now, the colourful part of your eye is called the iris, and the iris can change the size of your pupil with tiny muscles.

And this controls the amount of light entering your eye for you to see.

Let's do a quick check of your learning so far.

So what must happen to allow us to see things? Is it A, light must bounce off the surface of the eye, B, light must turn the eye on, C, light must enter the I, or D, light must out of the eye? So again, I'll give you five seconds to think about your answer, but if you need longer, you can pause the video here and you can come back to us when you are ready.

Off you go.

Fantastic.

Well done.

The answer is C, light must enter the eye.

Now, what is the name of the opening that allows light to enter the eye? Is it A, the iris, B, the muscle, or C, the pupil? Again, 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.

Fantastic.

Well done.

The answer is C, the pupil, the dark bit in the centre of your eye.

Now, here is your first task and it says, work with a partner.

It says to go outside on a sunny day or to a bright room and look closely at your partner's eyes.

What do you observe about their pupils? Now, next thing that you're going to do after that is you're going to ask your partner to close their eyes for one minute.

When they open their eyes, what do you observe about their pupils? Now, I want you to try to explain what has happened and why using these keywords, light, eyes, pupil, travels, light source, enter, bigger, smaller.

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

Off you go.

Fantastic.

Well done.

So remember, we are trying to explain what happens to our pupils in different amounts of light using the words, light, eyes, pupil, travels, light source, enter, bigger and smaller.

So light travels from a light source and enters the eye through the pupil.

In bright light, the pupil gets smaller.

In darkness, the pupil gets bigger so that more light can enter the eye.

Now, in bright light, the pupil gets smaller so that less light can enter your eye.

And in darkness, the pupil gets bigger so that more light can enter your eye.

Now, we are on to the second part of our learning today, which is using scientific models and diagrams. So it's important for scientists to help other people to understand how the world works.

And they can represent their ideas in different ways.

Now, scientists often use models to explain things that are too small, large, far away, complex, or difficult to observe or explain directly.

Now, here we have a model showing how objects move in space.

So this is an example of a model that scientists might use.

Last week, Laura's friend made a model using wool to explain how light travels from a light source to an object.

So Laura's friend had the torch, the wool, which represented the light, and the pencil.

Laura wonders what changes she needs to make to this model to show how light travels into our eyes.

What do you think? I'll give you five seconds to think about your answer, but if you need longer, that's absolutely fine.

Just pause the video here and come back when you are ready.

Off you go.

Fantastic.

Well done.

So Laura rolls out the wall so that it points towards her friend, Aisha, instead.

Has Laura made an accurate model to show how light enters our eyes? What do you think? I'll give you five seconds to think about your answer, but again, if you need longer, just pause the video here.

Off you go.

Fantastic.

Well done.

So I want you now to think about what Laura could do to improve her model.

See if you said that Laura had not made an accurate model to show how light enter our eyes, what could she do to make this accurate? How could she improve it? Again, I'll give you five seconds to think about your answer, but if you need longer, just pause the video here.

Off you go.

Fantastic.

Well done.

So an accurate model would need to show the torch, the wool, which you're representing the light, and Aisha.

Now, the wool is pulled tight because light travels in straight lines.

Remember, it doesn't travel in waves.

And the wall is touching the torch to show that the light is coming from the torch and the person's eye because we see things when light enters the eye.

So if you remember the previous model that was not correct, the wool was not in a straight line, it was curved and it wasn't touching the torch or Aisha's eye.

So we need to make sure that when we are drawing a diagram that it's scientifically accurate.

Now, you must ensure that it does not touch your eyeball.

Now, scientists also use a type of drawing called a diagram to record how we see things.

So here is Laura's diagram.

Now, Laura draws a diagram to show what she's been learning.

What should Laura do to improve her diagram? So I want you to think really carefully about what we've just learned about creating a scientifically accurate diagram.

Now, what could Laura do to improve this? I'll give you five seconds to think about your answer, but if you need longer, that's fine.

You can pause the video here and you can come back when you are ready.

Off you go.

Fantastic.

Well done.

So Laura's friends explain how to draw a scientific diagram correctly.

So Alex says, "You need to draw all objects in 2D from the side and do not colour them in." John says, "You need to draw an arrowhead in the middle of the line to show the direction that light is travelling." And Aisha says, "You need to draw light travelling in straight lines using a ruler." So Laura draws a scientific diagram to show how we see light from a lamp.

So she's remembered to draw a simple diagram of a lamp.

So it's 2D, it's simple, and it's from the side.

She's drawn a simple diagram of an eye from the side, and it's 2D as well.

And she has joined the lamp to the eye using a straight line drawn with a ruler.

And it's so important to make sure that you are using a ruler to do this so that your line is not wavy, because remember, we need to be scientifically accurate.

And the last thing that she's remembered to do is to add an arrow to the line to show the direction that the light is travelling in.

Now, let's do a quick check of your learning so far.

It says which of these are reasons that a scientist might use a model to explain something? Is it because A, the real version is too far away, B, it's easier to simplify with a model, C, making models with clay is an important scientific skill, and D, the real version is too big or small to see.

So I want you to think really carefully about this question.

So I'll give you five seconds now, but if you do need longer and you need to reread some of these statements, you can just pause the video here and then you can come back once you have an answer.

Off you go.

Fantastic.

Well done.

The answer is three of them.

It's A, B, and C.

So it's the real version is too far away.

It's easier to simplify it with a model.

And the real version may be too big or small to see.

Which of these diagrams should you do when you draw a scientific diagram? Should you, A, draw objects in 2D, B, colouring objects, C, use a ruler for straight lines, and D, draw objects viewed from above? So again, 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.

Fantastic.

Well done.

So the answers are A and C.

Brilliant job.

Now, your second task for today.

It says to use models and diagrams to show that we see things when light travels into the eye.

So you are going to make a model, first of all, to show this.

And then you are going to draw a scientific diagram to show this.

So remember, your drawing should be in 2D, show objects from the side, have straight lines drawn with a ruler, including an arrow to show the direction of the line, and it should not be coloured in.

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

Off you go.

Fantastic.

Well done.

So this could have been what your model looks like.

So this person here says, "I taped the string to the lamp and then held it taut next to my eye to show light travelling from the bulb to my eye." So remember, in your model, you don't want the string to actually be touching your eyeball 'cause that's quite dangerous.

And then here is a scientific diagram to show how the light from a lamp travels and enters our eye.

And this person has remembered to include a 2D diagram.

It's not shaded in, it has the arrow in the middle or the lines drawn with a ruler, and it's a fantastic example.

Now, onto the summary for today's learning, we need light to see things.

We see things when light enters the eye.

The pupil of the eye is an opening that allows light to enter the eye.

Scientific diagrams and models can be used to show how light travels in straight lines and enters the eye.

You have worked so hard today.

I am so proud of your learning.

You have worked brilliantly and you've used your critical thinking as well.

Well done.