Lesson video

Hello again everybody, for those of you who are new and just joining us on our science learning journey, or for those of you who might have forgotten, my name is Miss Simkin and I am delighted to be teaching you a science lesson on rocks today.

A new thing that I've tried to keep myself entertained this week is some planting.

So here are two little plant pops that I've planted this week.

So this one is hopefully going to sprout and become, forget-me-nots and this one is going to become some basil.

So hopefully we can check back on those in a couple of weeks and see if any progress has been made.

And I've also got this little peepul here that was sent to me in a test tube and I've now replanted into this pot so we can keep an eye on this little fellow too.

Today, we are going to learn about a third type of rock.

So our lesson today is all about sedimentary rock.

For today's lesson, all you will need is a piece of paper, a pencil, and a colouring pencil if you would like to correct your work in a different colour, as we go through.

In today's lesson, we will go through our star words like we always do, then we will do some recap of our knowledge from lessons one on igneous rocks and lesson two or metamorphic rocks.

Then we will learn about off that type of rock, sedimentary rock.

And we're going to look at the steps that are needed to form sedimentary rock.

Then our lesson is going to take a turn and we are going to learn about fossils.

And we are going to learn what a palaeontologist does.

So these are our star words for today.

We have lots of style wars today, we're going to practise saying them all.

Some of them are quite long, so you might need to say them a few times.

I'm going to say the first that I'm going to point at the screen, and it's going to be your turn to say them.

Sediments, your turn, sediments.

Great, pressure, your turn, pressure.

Palaeontologist, palaeontologist.

Great, that's a tricky one.

Fossil, brilliant, sedimentation, your turn.

Compaction, compaction.

Cementation, cementation.

Great, and sedimentary rock.

Brilliant, we're going to learn what most of those words mean as we move through our lesson.

But before we begin, I want us to talk about the two words that are underlined.

So the first one is sediments.

Sediments or small fragments or pieces of rock and soil.

And pressure is a word that we looked at last lesson.

Pressure is a force, okay? So when we put pressure on something, is a type of force.

At the moment, I'm putting pressure on my other hand.

We learned about pressure when we learned about metamorphic rocks, 'cause pressure is one of the things that can change other rocks into metamorphic rocks.

It's going to be important in our sedimentary rock lesson too.

Let's start by recapping some of our previous learning.

You may have already had a go at your pre-lesson quiz.

If you haven't, then pause the video and go and do that now.

And in our recap, we're going to go through some of the answers that you would have done in your quiz.

Well done if you got them right, but no problem if you made a mistake, because that is how we learn and we're going to go through the correct answers now.

So rocks, we learned that rocks are made of solid grains that fit together.

We learned about two types of rocks so far in our learning.

So the first is igneous rock, and there's a picture there to remind us how igneous rock is made.

If you can remember how igneous rock is made, then say it out loud to your screen, or you could even pause the video and write it down.

Igneous rock is formed when magma or lava cools and solidifies.

Well done if you remembered that.

How is metamorphic rock made? What does that picture remind us? Something to do with change.

If you know it, say it to your screen or you could pause the video and write it down.

So metamorphic rock is formed when pressure inside the earth changes igneous and pressure or heat inside the earth changes igneous and sedimentary rock.

And today we are going to add our final type of rock.

So we're going to learn about sedimentary rock and then we'll have learned about all three.

So when we learned about igneous rock, we learned that there were two types of igneous rock intrusive, and extrusive.

And intrusive was formed inside the surface of the earth, and we remember that because I, in intrusive and I, in inside an extrusive is outside.

And because they're built, because they're built, sorry, because they're made in a different way, they look different.

One of them had big grains and one of them had small grains.

Can you remember which was which? Think about the letter.

Great, intrusive rocks had the big grain.

So the intrusive of rock is the bottom one on the picture.

And this was how we remembered it, intrusive, inside the earth, big grains.

Say that to your screen.

Great, well done.

So now let's look at our steps to form a sedimentary rock.

We're going to start with a demonstration.

So I'm going to show you a demonstration, which will hopefully help us to understand how sedimentary rock is made.

So I am going to make some sedimentary rock in this little pot.

And to help me, I have some grated chocolate.

Now my grated chocolate represents sediment.

And we've learned what that word means so far in this lesson.

So that's remind ourselves.

Sediment is small pieces or fragments of rock and soil.

So this grated chocolate is in small pieces.

So it's representing my small pieces of rock.

I'm going to put my sediment in this pot.

In fact, let me just move the screen a little bit so you can see more clear.

As you can you see that my sediment is building up.

And in fact, it's building up in layers as different types of sediment, so different pieces of rock, or different pieces of soil build up on each other.

So the sediments are building up on top of each other in layers.

Now imagine that this wasn't chocolate and it was actually sediments, so small pieces of rock.

The sediments at the very bottom, are going to feel the weight of the other sediments on top of them.

And pieces of rock, even if they're small, are quite heavy when they build up.

So there's going to be a pressure that is being exerted downwards on the bottom pieces of sediment.

Because the weight of the sediment is pushing down.

And as I add more and more layers of sediments, that pressure increases.

So I've got all my layers of sediment now.

The next thing that happens, is once all of the layers are built up, the pressure of them, forces the sediments to compact, that means squished together.

So you can see as I'm putting pressure on my sediments, they're squishing together like this.

This is exactly what happens when sedimentary rock is made.

Now, sorry, I'm making quite a lot of mess as you can see, because the chocolate is melting.

So now you can see that I have one solid piece of chocolate or in this case, if we were applying this to real life, it would be a solid piece of sedimentary rock.

The pressure has caused all the individual little pieces of sediment to be compacted together and form one solid piece, which is now not coming out of my pot.

So that is an example of how sedimentary rock is made.

And now I need to try and figure out how to flick back to the other screen without getting chocolate all over my laptop.

Great, so now we've looked at using chocolate to describe how sedimentary rock is made, let's see if we can break down what those steps are with some diagrams. So the first step in the process is called sedimentation.

Say it to your screen.

And sedimentation is when small pieces of rock and soil builds up in layers.

So that's what that picture there is showing, you can see there are different layers of small pieces of rock and soil that are building up.

That's our first step.

Our second step is called compaction, say it to your screen.

Compaction is when the weight of the sediments put pressure on the sediments at the bottom and this squashes the grains together more tightly.

So if we look at the difference between our two pictures, in our first one, the sediments have lots of space between them, but in our second one, compaction has occurred and the pressure has caused them to squish or squash together.

So you can see we've got a green arrow down there showing us the pressure.

Then in our third step, something called cementation occurs, say it to your screen, cementation.

This is when crystals form between the layers of the rock and stick them together.

So in this diagram, the crystals have been coloured orange.

That's to make them really obvious, they wouldn't necessarily be orange in real life.

This has been crystals form between the layers of rock and stick them together.

So you might have heard of cement before.

Cement is what builders and contractors use to stick bricks together.

So that will help us remember what cementation means because in cementation, the pieces of rock are being stuck together, just like when we cement bricks together.

So our three steps are sedimentation, compaction and cementation.

So first of all, small pieces of rock buildup, then the pressure squashes them down and then crystals form to cement them together.

I would like you please now to answer some questions on this.

This is a lot of learning, a lot of steps all in one.

So when you answer these questions, you might want to skip back to this part of the video and watch it again or maybe even pause the video on the screen so you can make some notes.

Here is the question I would like you to answer.

So I would like you please to draw a diagram and write a sentence for each step.

So sedimentation, compaction, and cementation.

You can pause the video and complete that now for me.

Great, well done, I would love to see a photo of those diagrams and sentences, so please feel free to send them in over Twitter.

We're going to go on to the next part of our lesson, which is all about fossils.

Now, the reason that we are learning about fossils when in our sedimentary rock lesson is because fossils are only made in one type of rock.

Fossils are made in sedimentary rock.

They're not made in metamorphic rock, they're not made an igneous rock, they are made in sedimentary rock.

So we're going to learn how fossils are made.

So these pictures are going to help me explain how a fossil is formed.

So first of all, an animal needs to die.

So in our example here in picture one, you can see that it's a dinosaur.

Now, we don't just have fossils of dinosaurs, there are lots of other animals that are fossils too.

We're going to see some examples later, but some of the most famous and most impressive fossils are dinosaurs, so that's the example that you've got.

So in step one, a dinosaur or an organism dies, and then it starts to decompose.

So that means that the soft parts of its body start to decay away.

Then over lots and lots of time, sediment begins to build up on that dinosaur skeleton.

So just like when we were in our example, when we were learning about sedimentation, those little fragments of a rock and soil start building up on our dinosaurs, so you can see that happening in number two.

Then in number three and number four, those layers keep building up.

And that's when compaction happens in number three.

So when the pressure of all those layers starts to compact the sediments, and then in number four, they start to, we have our cementation and crystals start to form, forming the rock.

And that means that our fossil now is inside our sedimentary rock.

So we started off with piles of sediments, but by the end we have a rock and that fossil has been in case within that rock.

So that's what a fossil is.

It's the remains of an organism that has been preserved inside a rock.

And then in number five, that's when the fossil might be discovered because it is now the rock on top of it has been worn away.

So it might be worn away by rain or wind over thousands and millions of years and then the fossil might be discovered.

Here's an example of some fossils.

So take a minute to have a look at the pictures on the screen.

What do you think those might be fossils of? The one on the left is a reptile, so it looks a bit like a lizard.

The one in the middle is some sort of fish, so you can see its fins.

And then the one on the far right, with the really long bits coming down like this, is maybe the hardest, it's actually a bat.

So it's the fossil of a bat.

So those long digits you can see extending would be what holds its wings up.

Now we are going to do a bit of a fossil quiz.

So I'm going to show you a series of organisms and I want you to guess which fossil would have matched that organism.

So we need to use our observation skills there.

So observation skills, and we need to see which fossil is a similar shape to the organism.

Now, remember when fossils are formed, they are only formed from the hard bits of organisms. So that's why in that back picture, we can't see the whole outline of its wings, 'cause that would have been a soft part of the organism's body and that decade away in the first step of fossilisation, we're just left with the hard bits.

So let's see.

As we go through these, I'd like you to write the answers down on your piece of paper.

So here's our first one, so you'd write number one.

And then do you think this fossil, this snail matches fossil A or fossil B? The correct answer is fossil A.

Well, if you got that right, you can give yourself a big tick.

So you can see that this fossil A is roughly the type of the snail's shell.

And remember the soft part is not part of the fossil, just the hard part.

This is our next one.

Have a look closely at it.

In fact I'm going to make it even bigger so you can see really clearly.

Fossils are not just formed from dinosaurs or even animals, you can also get fossils of plants.

So this is fern, which fossil do you think matches the fern? Is it A or B? Write it down on your piece of paper.

The correct answer is B, you can see roughly the shape.

So you've got the long part coming up the middle and then the individual leaves branching out from it.

But then if you've got that correct, give yourself a big tick.

This is our next one, so this organism is called an ammonite and it's an extinct marine creature with a tightly coiled shell.

So extinct means that this organism doesn't exist anymore, we're going to be looking at extinctions later on in our learning.

It has hollow chambers in it's shell which helps it to move through the water.

Which fossil do you think matches this organism, A or B? Write your answer down on your piece of paper.

The correct answer is B, good job.

So remember, it's just the hard parts that are fossilised from organisms so you can only see its shell.

You can see that tight coil shape really clearly.

This is our next fossil, it's our last fossil.

This is called a trilobites.

A trilobite is a marine arthropod.

So it comes from the same group as things like wood lice.

And in fact, it looks a little bit like the wood lice that you might find in your garden.

But it's marine this one, so it used to live in the water and they were very successful early animals.

So there used to be lots of them around.

Their bodies are split into three ridged sections.

So you can see really clearly the front section where it's headed is, and then it's got two further sections at the back or ridge, they've got little segments behind them.

So can you figure out which fossil would fit our trilobite? I'm going to make it bigger so you can see really clearly.

Do you think it's A or B, write the answer down on your piece of paper.

The correct answer is A.

You can see on the fossil on A, it's got little ridges that match the pattern on the trilobite's body.

B has a different pattern, it's got dots and B is actually ancient sponge.

So not the kind of sponge that you'd clean your house with or do your dishes with, but there are, there's an organism called a sponge that lives under water, and it's got lots of holes in it, like a sponge you might use to clean.

And so that's what fossil B is.

Well done if you got those right.

Let's move on now to the next part of our lesson.

We are going to learn about palaeontologists.

Have a go at saying that word with me, it's a long one, palaeontologists.

And one more time, palaeontologists.

Great, this word is quite tricky to spell.

It would be a very good word if you're ever doing a game of Hangman with someone.

What I'd like you to do actually, before we start is to just pause the video and practise, spelling this word three times on your piece of paper.

So pause the video and do that for me now.

Great, good job.

I've got three pictures on the screen, they are all palaeontologists, all of the people.

I would like you to take some time to look at the pictures and have a think to yourself, what do you think a palaeontologist might do? It's a type of scientist, but what does a palaeontologist do? You might want to write your ideas down on your piece of paper.

I'm going to make it bigger so you can see really clearly.

Great, so a palaeontologist is a type of science that studies fossils, and they do that to learn what life on earth used to be like.

If we can understand what life on earth used to be like, it can help us understand more about the animals and the organisms that live on life today.

Just like how we might study human history to learn more about humans today and our actions as humans today, we can also study the history of fossils and organisms. So in the past, there are lots of organisms that have now become extinct.

So they died out and they don't exist anymore.

If we study fossils, then we can try and learn why those animals became extinct.

And that can help us try to stop animals that are alive today becoming extinct.

And that's a really important thing to do because it can help us to protect the animals that live in our planet today and the environments that they live in.

Now, a palaeontologist does lots of different things.

So you can see in these pictures, that part of their job is to work outside in the field, finding fossils.

So with that picture in the middle, they've just after a big fossil from a piece of rock.

So the palaeontologists would need to work carefully to use tools and brushes to remove those fossils.

Then you can see in the picture on the left that often they will take those fossils back to a science lab and they will study them really closely there.

I'm going to tell you that about a famous palaeontologist called Mary Anning.

So Mary Anning was alive a long time ago, that's why we don't have a photo of her, we just have this painting here on the left.

Next to her, you can see an example of a fossil of an organism called ichthyosaur.

Now this was the first full ichthyosaur fossil ever found.

It's quite common to find fossils that are only parts of animals, it's really rare and hard to find fossils of a whole organism.

So this was a really great fossil to find.

Now, Mary Anning found this fossil at the age of 11.

So she was really close to your age when she found it.

Fossil hunting became a lifelong passion of hers and lots of the fossils that she found are still studied by scientists today.

She went on to make many more incredible discoveries in her life, and she discovered a long-necked reptile called a plesiosaur and also a flying reptile called a Dimorphodon.

So she really was a fantastic scientist and a fantastic palaeontologist.

Now, how can palaeontologists like Mary Anning, tell where their fossils come from? How can they tell what age they are? Now, they can tell because of the way that sedimentary rock is made.

Remember we learned that sedimentary rock is made in layers like this of sediment that builds up over time.

That means that the sediments at the bottom are going to be older because they're the ones that were put down first and then the ones at the top, the ones that were deposited put down last, so they're going to be youngest.

That means that we can tell the age of the fossils too, because if a fossil is trapped between layers of sediment or rock down at the bottom, then we know it's a really old fossil.

Whereas if it's trapped at the top, then we know it's a newer fossil.

So that's how palaeontologists can tell how old fossils are.

They can tell how long ago those fossils were formed.

I have some questions for you now.

Your questions are, what does a palaeontologist do? How was the ichthyosaur fossil that Mary Anning discovered different to those discovered before? And then can you complete the gaps in this sentence below, overall, the closer the rock to the surface, the hmm the rock is.

This means that fossils found here are hmm.

You can now pause the video and complete these answers.

Remember if you need help, you can always skip back in the video.

Great, let's check our answers together.

You can tick your answers in a different colour and no worries if you made a mistake, just correct them using the ones on the screen.

Number one, palaeontologists study fossils to learn what life on earth used to be like.

You might have written a different wording to me, that's okay as long as you have the same main ideas.

Number two, it was the first complete ichthyosaur fossil to be discovered, that's why it was different to the ones that have been discovered before.

And number three, overall, the closer the rock to the surface, the newer the rock is, which means the fossils found here are younger.

You might have also written the fossils found here are newer, that means the same thing, good job.

That brings us to the end of our lesson.

So we have now learned about three types of rock, well done.

We've learned about igneous rock that is formed when a magma or lava, cools and solidifies.

We've learned about metamorphic rock, which is formed when heat and pressure inside the earth change igneous rock and sedimentary rock.

And now we have also learned about sedimentary rock, which is formed when pressure from layers of sediment causes the sediment to compact and cement.

So well done.

Let's look at our star word before you go and do your post-lesson quiz.

Our star words are sediments, which are small fragments of rock and soil.

Pressure, which is a measure of force or is a type of force.

Palaeontologists, which are scientists that study fossils.

Fossils, which are the remains of organisms preserved in rocks.

Sedimentation, so that was our first step in forming the sedimentary rock and that's when fragments of soil and rock build up on top of each other in layers.

Then we had compaction, that was our second step in how sedimentary rock is formed.

And that's when the pressure of all those layers start pushing down on the sediments and forming rock, and then cementation, our third step in our process of forming sedimentary rocks.

And that's when crystals start to form between the sediments, which stick and glue the rocks together.

And lastly, we have sedimentary rock, which is the third type of rock we learned about.

Well done everybody for all your hard work today, I am really, really proud of the hard work you've been doing so far and I'm really excited for our next lesson, where we are going to be classifying and identifying different types of rock.

See you soon, bye.