Lesson video

Hello, scientists.

My name is Mr. Wilshire, and in this lesson, we're going to be looking at protecting our eyes from the sun.

This is the do and review stage.

The outcome for this lesson is I can carry out and review an investigation about sun protection.

As always, there are some key words for us to consider as we work our way through this lesson.

The first is sun.

The next is ultraviolet, or UV.

Then, it's exposed.

After that, it's review.

And finally, conclusion.

Don't worry if you're not too sure what some of these words mean.

The meanings have appeared on the screen for you now, so you can have a look at the definitions and remind yourself before moving on.

Pause the video now and do that if you need to.

The first part of this lesson is called The UV index.

Jun and Izzy are playing outside.

The sun is up in the sky and it's shining very, very brightly.

I don't think there's any clouds either.

Jun says, "I put on sunscreen to protect my skin before I came outside to play," and Izzy says, "Well, I'm wearing sunglasses to protect my eyes from the sun's UV rays." I wonder if you've ever been outside when it's really sunny like this.

Did you make sure that you wore some sunscreen, and did you wear some sunglasses? Or maybe you wore a hat to protect your head? I don't think that going outside wearing a scarf and a woolly hat and gloves is going to be a good idea here, is it? Light from the sun can be really dangerous, so it's very important that we protect ourselves in different ways.

First of all being, you should never ever look at the sun.

That's why there's that caution mark there in the triangle.

The sun can really damage your eyes, so whether you have sunglasses on or not, it's not gonna protect you as much.

Izzy says, "I only wear sunscreen and sunglasses in the summer.

Does the sun only give out UV rays in this season?" What do you think? Does the sun only give out UV rays during the summer? Pause the video here and discuss.

Well, what do you think? Is the summer the only time that the sun can give out UV rays? The other seasons are autumn and winter and spring.

Summer's the hottest, so surely that must mean that the UV rays are the most lethal then.

Jun says, "No, the sun is always giving out light, but there are higher levels of ultraviolet light in the summer." Ah, okay.

So that means then you need to be extra careful in the summer, but the rest of the seasons, well, you might need to be careful of the sun as well, especially if it's a warmer day than normal.

Izzy continues to say, "Even though the sun is always producing light, I don't need to protect myself when the weather is cloudy." Hmm, okay.

So the clouds do block the sun.

So does that mean that they always block the UV light rays as well? Do you agree with Izzy here? What do you think? Sam says, "A cloudy and cool day might have a low temperature but high levels of ultraviolet light.

If the clouds are thin, they will allow UV rays to pass through." That's true.

Sometimes you can still see the sun slightly through the cloud.

So if the clouds are very thin, the UV rays are still likely to be able to burn your skin.

Let's stop and think.

Which statements about the sun are true? Is it that the sun only gives out light during the day? Is it that the sun only gives out light in the summer? Is it that the sun is always giving out light? Or is it because there are higher levels of ultraviolet light in the summer? Think about the correct answer here, pause the video, and restart when you've done that.

The correct answers here is C and D.

The sun is always giving out light, whether we can see it or not.

There are also high levels of ultraviolet light in the summer.

Izzy said, "Well, my sister told me to check something, it's called the UV index, but I don't know what that is." Sam says, "Well, I think that UV stands for ultraviolet." Do you know what the UV index is? Does UV stand for ultraviolet? What do you think? So what did you think? Does UV stand for ultraviolet? Izzy's sister says, "The UV index is a set of numbers that tells us how strong the sun's damaging ultraviolet rays are." Here you can see an example of the UV index.

You can see that when there's not a lot of sun, the level is low at 1 or 2, and it goes all the way up to 11+, which is very extreme.

That's when you should stay inside, whereas the low section is when you don't need much protection at all.

Izzy's sister continues to say, "The higher the number, the less time it takes for your skin to become damaged when exposed to UV rays from the sun." So when it's at 11, that means your skin could get damaged very, very quickly.

Remember, ultraviolet light means a light that we can't really see.

Sam says, "When we expose our skin to the sun, it means that we are putting it in sunlight and without any protection, such as sunscreen or a long sleeve top." A UV level of 2 or below is considered low risk, and sun protection is not considered necessary.

However, when the UV index reaches a level of 3 or above, which is moderate, sun protection is recommended.

And in fact, it goes all the way up to 11+, where the best sun protection is actually just staying inside.

Do you remember a time when it was so hot and so bright outside that it was better to stay inside? Lucas says, "I only wear sunscreen and sunglasses when I go to a sunny country on my summer holiday." What advice would you give to Lucas here? Is that the best thing to do? Pause the video and discuss.

So what did you think? Is there any other advice that you could give to Lucas here? Laura says, "It's important to protect yourself from UV light from the sun in the UK too." So just because you're on holiday doesn't mean that's the only time that you should wear sun cream.

The sun can get very, very hot and very, very bright in the UK as well, so it's always best to protect yourself anyway.

In the UK, light from the sun is often strong enough to cause skin damage between mid-March and mid-October.

The sun's rays are strongest in the middle of the day, which is 11:00 AM till 3:00 PM in the UK.

That's when you may find it's particularly hot.

Let's stop and think.

What does the UV index tell us? Does it tell us how hot it is? Does it tell us how strong the wind is? Does it tell us how strong the sun's UV rays are? Pause the video here and think.

Restart when you've done that.

The correct answer here is C, how strong the sun's UV rays are.

Izzy and Alex have been using UV changing colour beads.

They're using them to measure the levels of ultraviolet light from the sun.

Here you can see examples of UV beads in a dark room, and then UV beads which have been outdoors on a sunny day.

You can see that they really react to the sun, can't you? Alex says, "The beads change colour when left in UV light.

The darker the colour of the beads, the more UV light that they've been exposed to." They plan their own inquiry to find out which sunglasses are best at protecting our eyes from the sun.

Alex says, "We plan to use some UV beads and place them under the lenses of three pairs of sunglasses outside on a sunny day.

After five minutes, we'll take the sunglasses away and quickly take a photograph of the beads to record what colour they are.

We'll test a group of beads too with no protection from sunglasses." There's a reminder here as well to never look at the sun.

Stop and think.

Who do you agree with here? Aisha says, "UV beads change shape when exposed to UV light." Sophia says, "UV beads change size when exposed to UV light." And Jacob says, "UV beads change colour when exposed to UV light." The person I best agree with here is Jacob.

Now, UV beads change colour when exposed to UV light from the sun.

Here's your first task.

Carry out an inquiry to answer this question: Which sunglasses are best at protecting our eyes from the sun? Alex says, "Use your own plan or our ideas on the next slide to carry out your investigation." Izzy says, "You'll need to decide how to record your results." Okay, so you can come up with your own ideas here or you can use this next slide.

Alex says, "We've included this information in our plan." They're going to change the type of sunglasses.

They're going to measure the colour of the UV beads after five minutes of sunlight.

They're gonna keep these things the same: the number of beads, the location of the beads, and the amount of time in the sunlight.

So it's over to you now.

Either come up with your own idea for your own investigation, or you can have a go now investigating using these ideas here.

Best of luck with your task.

See you in a moment.

How did you get on? Were you able to carry out that inquiry, or did you use the plan here? They said, "Here are their different testing sunglasses, 1, 2, and 3.

We also left the same amount of beads in the sun with no sunglasses to protect them." That's a good idea, and we can find out what happens if you're not wearing them at all.

Hopefully, you were able to record some of your results in a table here.

On the next few slides, we'll be reviewing the inquiry and finding out the answer to the question.

The final part of this lesson is called Reviewing an inquiry.

Alex and Izzy observed the photograph they took before the UV beads had been exposed to the sun.

There's a picture there before testing.

They're all very white and clear, aren't they? Alex says, "To observe we use our eyes and sometimes some other senses too." Izzy says, "Before testing, I observed the beads to be white in colour." Yeah, I agree with Izzy too.

Here are the photographs that Alex and Izzy took after the UV beads have been exposed to the sun.

Sunglasses 1: there's a couple of white ones, and they're all about the same kind of purple.

Sunglasses 2 shows that there's one dark purple there.

And sunglasses 3 was very similar to sunglasses 2.

With no sunglasses at all, though, all of them have changed, haven't they? What observations can you make by looking at these pictures? Have a look and have a discussion.

Restart when you've done that.

Careful observations should be made when comparing UV beads.

Izzy said, "I observed that all of the UV beads look more colourful after five minutes outdoors in the sun." So the UV rays are definitely there, aren't they? You can see that because the UV beads are picking that up by changing colour.

Do you agree with Izzy here? Pause the video and restart when you've discussed.

What do you observe? Alex says, "Well, I observe that the UV beads that were under the lens of sunglasses 3 are darker colours than the UV beads that were under sunglasses 1." Good observations, Alex.

Well done.

I wonder if you found the same by looking at these pictures.

What do you observe? Alex says, "I observe that the UV beads that were not under the lens of the sunglasses have changed colour the most and are darkest." There you can see the two pictures, and that's another good observation.

Did you observe the same? Stop and think.

Whose observations do you agree with here? Aisha says, "After five minutes in the sun, I observe that the UV beads have not changed colour, so that they've not been exposed to UV rays." Jun says, "After five minutes in the sun, I observe that these UV beads have changed colour, so that they have been exposed to UV rays." Who do you agree with? The person I most agree with here is Jun.

You can definitely see the difference.

These beads have detected that there's UV light.

What do we do when we observe what is the same and what is different about objects? Do we group them, compare them, or identify them? The correct answer here is compare them.

It's best to compare.

That's why it's good to have a control set of beads too.

When scientists look over what they did and what they found out, this is called a review.

Izzy said, "Alex and I reviewed our inquiry and talked about what we had observed." Why do you think it's important to do this? Pause the video here and discuss.

So why is this so important to do this? Let's find out more.

Well, it's important to review an inquiry because we might suggest changes and consider whether it could be improved.

It's always good to check your own work, isn't it? 'Cause then you might be able to do it better next time.

Scientists also review what they have learned so that they can write a conclusion about this.

They can then share this with other people.

What's a conclusion? Pause the video and discuss.

Izzy's got the answer for us.

She says, "A conclusion is when we explain what the results of our inquiry show or mean." So Alex and Izzy review their results to start making their own conclusions.

Alex says, I observe that the UV beads that were not under the lens of the sunglasses have changed colour the most and are darkest." There you can see a picture of the UV beads that were not under the lens of the sunglasses.

So what does this tell us then? Have a think.

This is what it tells us.

Alex has done his own conclusion.

"My conclusion is that the beads that were not under any sunglasses were exposed to the most UV light.

This means that all of the sunglasses we tested can give us some protection from the sun." What conclusions did you make? Do you agree with Alex? Discuss.

I wonder if you agreed with what Alex says here, or maybe you have some different conclusions of your own.

Izzy says, "I observe that all of the UV beads that have had exposure to the sun have changed colour after five minutes." Oh, that's another good observation there as well.

What does this tell us though? Do you agree with Izzy? Did you agree with Izzy? Izzy says, "Well, my conclusion is that all of the beads have been exposed to some UV light.

This means that none of the sunglasses provided full protection from the sun's harmful rays." You can see that they've given a little bit of protection because some of the beads there aren't coloured at all, are they? So there is some protection, but it's not full protection, is it? I wonder what other conclusions you made.

Stop and think.

Which of the following skills do we use when we look at what we've done after we've completed an investigation? Researching, reviewing, or recording? The correct answer here is reviewing.

It's always best to review what you've done.

So here's the final task.

You need to review here.

Your need to review your results of the inquiry in task A.

Write your own conclusion based on your results, or you could use Alex and Izzy's results to help.

Remember to answer this inquiry question: Which sunglasses are best at protecting our eyes from the sun? Here are Alex and Izzy's results.

You can use these if you need to.

Best of luck with your task.

See you in a moment.

How did you get on? Here's Alex's conclusion.

He says, "My conclusion is that sunglasses 1 let less UV light through than the other sunglasses.

This pair would be best at protecting my eyes from the sun, although they don't offer full protection." Remember, your results might be different to this.

Izzy said, "I observed that the UV beads all changed colour when exposed to the UV light from the sun.

The beads that were not covered by any sunglasses changed the most and are the darkest colour.

This means that they've been exposed to the UV light the most.

The UV beads that were under the lens of sunglasses 1 have changed the least and are the lightest in colour.

This means that they let the smallest amount of UV light through.

I would wear these sunglasses because they'll be the best at protecting my eyes from UV light." That's a great conclusion there, Izzy.

She's obviously thought about everything.

I wonder if your experiment was the same and if you had different results or similar results.

Let's summarise our lesson.

The sun is always giving out light, but there are higher levels of ultraviolet light in the summer.

The UV index tells us how strong the sun's damaging ultraviolet or UV rays are.

Ultraviolet-sensitive beads change colour when exposed to UV light from the sun.

Careful observations should be made when comparing UV beads before and after they've been exposed to the sun.

Scientists often review a completed investigation and write a conclusion.

Well done for completing the task and reviewing everything as well.

Hopefully now you've got a better idea of how to be safe in the sun, especially when wearing sunglasses.

Maybe you can have a go doing some different investigations using UV beads.

I've been Mr. Wilshire.

Thank you very much for listening.