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Hi everybody, it's Miss Simkin back again for your next science lesson.

I am having so much fun learning all about rocks with you.

And I'm really excited for today's lesson.

So let's begin.

In today's lesson, we are going to look at the lesson question, how can we identify different types of rock? For today's lesson, you are going to need a piece of paper or a exercise book, a pencil, maybe some colouring pencils could be useful towards the end of the lesson and you're definitely going to need a ruler.

So if you don't have those things, could you pause the video and go and get them now please? Great, so let's begin with our star words or key vocabulary for today's lesson.

We're going to start by saying each one.

And then I will define the words for you.


Identification key.

Identifying, great.



Good job.

So we're going to talk about what three of these words mean.

And then in the lesson you'll find out what an identification key is and what a geologist is, if you don't already know.

Observing means when you collect information about something.

So when we observe, we observe with all of our senses.

So we might write down what we see, what we hear, what we smell and what we can feel.

When we identify, that means we decide what something is.

And we're going to be identifying today 'cause we're going to be looking at different rocks and deciding what type of rock they are.

Characteristics are the traits of something they're how you would describe something.

So for example, the characteristics of this piece of paper are that it's white and it's lined.

Or the characteristics of my hair is that it's very long and blonde.

Today we're going to talk about the characteristics of rocks.

So we're going to be describing different rocks.

This is what we're going to be doing.

We're going to start with some quick recap.

Then we're going to learn about what a geologist is and then we're going to be geologists today.

We're going to make observations about rocks.

We're going to identify rocks and we're going to create our own identification keys.

Let's start with some recap.

Let's wake those memories up and see how much you can remember from our previous lessons.

So there are three main types of rock.

Can you remember what they are? If you can say it to your screen.

Igneous, metamorphic and sedimentary.

Well done if you remembered.

So the first type is igneous, my turn igneous.

Can you remember how igneous rock is made? It's formed when magma or lava cools and solidifies.

What about metamorphic rock? Can you remember how metamorphic rock is made? This is the one that starts with the two other types of rock and if you can remember say it to your screen.

Here's a handy hint, a picture to remind you.

What does that represent? Metamorphic rock is formed when heat or pressure inside the earth change igneous and sedimentary rock.

So remember this picture represents the rock that we start with and that green arrow is representing the change to our new metamorphic rock.

And what could be causing that change is heat or pressure inside the earth.

And lastly, we have sedimentary rock.

Here's our picture to help us remember.

Can you remember how sedimentary rock is made? Say it to your screen.

Great, sedimentary rock is formed when the pressure from layers of sediment causes the sediment to compact and cement.

Well done if you remembered those.

So today we are going to be geologists.

Here is a picture of a geologist.

Geologist is a type of scientist.

Can you guess from the picture or maybe from our topic, what kind of scientist a geologist is? Have to think for me.

A geologist is a type of scientist who studies rocks.

What does a geologists study? Rocks, exactly.

And they study rocks to learn more about the earth.

Geologists do lots of different things in their jobs.

They might work in the field where they're collecting and studying the rocks in situ, that means in the environment that they're found in.

They might educate other people.

So they might give tours around national parks.

Or they might work in the lab where they bring rock samples back and they study the chemicals that they're made of and their composition.

There is just so many things that geologists might do.

This is one of the many tools that geologists use.

So this is called an identification key, my turn identification key.

Great, an identification keys help us to identify something, to decide what it is.

And they work by giving you a series of questions or descriptions that you follow until you get the correct answer.

So let's have a go at using this.

You can see a picture of a rock on the page, so have a look at that rock.

We're going to follow the key down and this is called a branching key 'cause it has different branches until we get to an answer.

So if we start here at the top and we look at our first two options, we've got grains not arranged in layers or grains arranged in layers.

Which do you think best describes our rock? Have a look at it.

Point to the option.

Yeah, this one.

I think we could say that these grains are arranged in layers 'cause I can see the layers, I can see the stripes in it.

So that means I'm going to follow this branch down.

And now I've got four options that I'm going to choose from, which one best describes our rock.

Let's look closely and have a think.

White rock that's very hard.

Hmm, I don't think I would describe our rock as white.

Grey or purple rock, very hard and brittle, splits into thin sheets.

It doesn't look like this rock would split into sheets.

It does have some grey in it, but I can't see any purple.

So I don't think so.

Silvery coloured flaky grains.

It's a bit silvery but I still wouldn't describe it as just silvery.

Rock shows dark and light bands.

Ah, I think that's the best description of our rock 'cause I can see those bands, those lines.

And so now if I follow that branch down it gives me an answer.

That means that this rock is called gneiss.

It's silent G.

Gneiss, okay? And that's how I can identify this rock by answering the questions and following the branches.

And at the end of the lesson we're going to make our own version of this.

So today we're going to be geologists and we're going to imagine that we are working in the USA, in Rainier National Park.

And we are going to collect some rock samples.

We're going to describe the rocks, we're going to identify the rocks and then we're going to make our own key.

So let's start with our observations.

Here are three examples of rocks on the screen, A B and C.

I'm going to give you a minute just to look at them.

So when we're making observations about rocks when we're describing them, there are four main characteristics that we want to think about, and those are on the left in purple.

So we want to think about their colour, their grain size, you remember rocks are made up of little grains and sometimes we can see those grains, sometimes we can't, sometimes they're small and sometimes they're big.

Can think of grains like grains of sand.

We want to think about their patterns.

So they could be stripy, spotty, blotchy, speckles.

And we want to think about the texture.

Texture is the way things feel, okay? Can you say texture and do the action for me? Texture.


So, let's have a go at describing these rocks.

I'm going to start with rock, rock B.

I think that the colour of rock B is grey.

It's grain size? Hmm, I'm not sure I can see it grains, not from this picture.

So maybe they're too small to see.

Patterns are, this rock is filled with little holes, isn't it? So it's got kind of a spotty pattern and its texture is like bubbly or it's got air bubbles in it.

Can you have a go at describing rock A? So you think about the colour, the grain size, the patterns and the texture.

You can just do it by speaking.

Pause the video and describe rock A to your screen.

Great, good job.

So you might have said it was green, that you can't really see the green, the grains.

It's got a spotty speckled pattern and that rock looks quite smooth.

C is an example of a rock where you can, the grain size is actually quite interesting because you can't see little grains but you can actually see other rocks within that rock.

And we're going to have a look at some different rocks like that today.

So, now I'm going to show you five rocks.

Here's our first one, rock one.

And these are the five rocks that we've collected from Rainier National Park.

And what I want you to do is I want you to get your pencil, and I want you to write down this time your observations about each one.

So for this you're going to write rock one, can you write rock one for me now.

Great, and you're going to make some notes, they can be short bullet points about the colour, the grain size, the patterns and the texture of this rock.

Here are some key words to help you with grain size.

So, maybe these are the options.

Is it too small to see? Are they big grains, small grains, crystals like salt or large chunks like that last rock we saw where it had other rocks in it, okay? Can you pause the video and make some notes about rock one? Brilliant, good job.

Okay, so here's your second rock.

Can you write rock two and pause the video and make some notes about this rock.

Great, good job.

I can tell that you're looking really closely at the picture on the screen and taking your time to make some detailed notes.

Here's rock three.

Can you write rock three? This one might look familiar, we've looked at this rock before.

And can you make some notes? Make sure you're including all four characteristics, colour, grain size, patterns and texture.

Pause the video and do that for me now please.


So now that we can see this picture a bit bigger I can see that this grain size looks like it might have crystals in it.

You can see kind of squarish shapes that are a bit shiny, they look a little bit like soap crystals.

So I might describe this grain size as crystals.

If you haven't written crystals, maybe you could edit your work now in a different colour and add crystals in it as a description.

Good job.


Next rock we're going to look at is rock four.

Can you pause the video and make some notes about rock four? Great, good job.

So for this rock, we've got more than one colour so it's okay to write white and black and grey, okay? The crystals again, they look like they, sorry, the grain size looks like it might be crystals again and they're quite big, I can see the different grains.

And then the patterns, you might have written spotty or speckled, and the texture looks like it might be a bit rough.

Okay, and this is our last rock.

Can you pause the video and make some notes? Here are your notes about grain size to help you of your guess.

Great, good job.

So this is another example of one of those rocks where you can see chunks of other rocks in it, okay? So for grain size you might have written large chunks or something similar.

Well done.

So now we've made our careful observations about our rocks.

We're going to see if we can identify, if we can decide what type of rock each one is, what the name of it is.

So one of these five rocks that we've already looked at our collected samples is marble.

I'm going to read you a description of marble and you're going to decide which rock you think marble is, okay? So you can write down marble.

And the next thing you're going to write down one, two, three, four or five.

Listen carefully to the description and see if you can choose.

Pure marble is white.

It has a coarse texture that means it's quite rough and a crystalline structure.

So that means that you might be able to see crystals in it.

Can you pause the video and write down which rock you think is marble? So white and rough.


Next one.

The next rock is obsidian.

Obsidian is often called volcanic glass.

It forms when lava cools quickly.

Ooh, what kind of rock cools quickly or forms when lava cools? Can you remember? If you can say it to your screen.

Igneous, good.

So I knew that this rock is going to be an igneous rock.

Samples are usually black with a smooth shiny texture.

Hmm, which rock do you think obsidian is? Write down obsidian and then the number.

Pause the video and do that now.


Okay, we've got three more.

It's a bit like being a detective this.

Our next rock is called conglomerate.

That one's quite hard to say, let's practise.

My turn, conglomerate.

Good job.

Conglomerate is normally a mix of greyish colours.

It's clear to see big chunks or pieces of other rocks that have been joined together.

Hmm, which one do you think that is? Pause the video and write conglomerate and then the number that you think it is.


Our next rock is gneiss, but the spelling is a bit funny.

So make sure you're careful with the spelling, it's got a silent G.

So gneiss normally has a pattern of white, grey and black stripes.

Which rock do you think that might be? Pause the video and write down your answer.


Hmm, let's think for a moment about a stripy rock.

What kind of rock might have stripes in it? Think about how that rock might be formed.

What type of rock might have stripes? Now, if you know it say it to your screen.

Sedimentary rock might have stripes in it because when sedimentary rock forms, it forms from layers.

And so those layers appear as stripes.

Oh, now this is a bit tricky.

It could also be a metamorphic rock 'cause it could be some metamorphic rock that start as sedimentary rock, and then kept the pattern when it was changed into metamorphic rock.

Okay, our last one is granite.

So, you might have figured this out already 'cause it will be the only number left.

But let's listen to the description.

Granite is an intrusive igneous rock.

Hmm, can you remember? Does intrusive igneous rock have big grains or small grains? I was asked to keep here remembering.

Intrusive has big grains.

Well done if you remembered and it's usually composed of grains of different colours and it has a speckled pattern, so speckled means like spotted.

Which rock do you think it is? Pause the video and write down your answer.

Good work.

Let's mark your answers.

So rock one was obsidian.

Rock two was marble.

Rock three was gneiss, spelt gneiss.

Rock four was granite and rock five was conglomerate.

Well done if you got those correct.

Here are the answers again on the screen.

So if you need a bit more time to mark those and you can tick your answers or correct them if you need to, you can pause the video and do that now using what's on the screen.

Brilliant, good job.

So, that brings us then to our last part of our lesson.

We've described the characteristics of rocks.

We've identified them and now we're going to create an identification key which will help other students and other scientists to identify the rocks that we found as well.

I'm going to take you through the steps of how we would create an identification key.

And then at the end, you're going to draw your own.

So here's our example again.

Our identification key is going to look a little bit different to this, oops sorry, because we're going to create a dichotomous tree which means we'll only have two options each time just to keep it simpler, okay? We're going to create a dichotomous key.

My turn, dichotomous key.

Good, well done.

A bit of a mouthful.

So the first step when making a key is to list out all of the characteristics that you're going to ask questions about.

So we've already looked at, well we spent this lesson looking at colour, grain size, patterns and texture of rock.

And here's a reminder of the five rocks that we looked at and what they look like.

And for colour, these were some of the different options we had within our rocks.

So we had white, black and mix of colours.

For grain size we had big grains like in granite, smooth grains like in gneiss or grains that are too small to see like in obsidian.

For pattern we had stripes, we had speckled, we have some with no pattern.

And texture we have smooth and rough rocks.

So once we've listed down all of the characteristics, we need to think about which characteristics are the most general and which are the most specific.

We want to start with the most general ones, so things about colour maybe, and then we want to move down to the most specific, most specific characteristics.

The reason for that is that each time we ask a question we want to kind of identify one rock and then be left with the rest.

So we're going to start by identifying the most obvious rocks with quite general characteristics and then we'll be left with the trickier rocks at the end, the ones that are harder to tell the difference between and we'll ask really specific questions in order to do that.

So step two is to put those characteristics in order.

So from the most general to the most specific.

So we're going to start with colour, then texture, then pattern and then grain size, okay? If that sounds a bit confusing don't worry, it will become a bit clearer as I'm going through the questions.

Step three then is to create our questions.

So this is all of the planning stage of our key and we need to do this before we start drawing our key otherwise we might make mistakes when we draw our key and we'll have to go back and start again and that will take a long time.

So we're actually going to write down our four questions before we draw our key.

And our first question is going to be about colour, our second question about texture, our third question about pattern and our fourth question about grain size.

These are just annex to help us.

So the first question we're going to ask is going to be about colour and the two most obvious rocks that have like a clear colour are obsidian which is black and marble which is white.

So a good first question would be to identify one of those.

Now, I'm going to choose marble because I think that the only kind of defining characteristic about marble is its colour.

Whereas obsidian, I could talk about it being really shiny and smooth, and I can do that later on.

So these questions always need to have two options and the options need to be yes or no.

So an example of my question to identify marble could be, is the rock white? Okay? And the answer is either yes or no.

If the answer is yes, then it's marble.

If it's no, then we'll go onto our next question, okay? Don't worry too much about writing anything down now just listen to my thought process.

So I've got my first question, is the rock white? And I've drawn a little smiley face on marble 'cause we've now kind of identified that where we can take it out of our group.

We're just focusing on our four other rocks now.

The next rock I'm going to think about is obsidian and I'm going to think about its texture 'cause that's what makes it quite obvious to identify.

So what question could I ask about texture where the answer would be yes, obsidian? Something maybe like, is it shiny or is it smooth, okay? Because obsidian is my only shiny or smooth rock, okay? So if the answer is yes, it will be obsidian, if the answer is no, it will be one of my three rocks that are left and we'll go to the next question.

So now we've got obsidian with our smiley face 'cause we've identified that one as well.

When I look at my rocks now the next rock that I think is most obvious is maybe gneiss 'cause it's got that obvious stripped pattern.

And my third question is going to be about pattern.

So what question could I ask where the answer is yes, niece, oh sorry, gneiss? Maybe I could ask, is it stripy? So that's going to be my next question.

Oops, here we go.

Is it stripy? If the answer is yes, then it's gneiss.

If the answer is no, then I've got two rocks that it couldn't be.

Okay, so we've got my smiling face on gneiss 'cause we've identified that one now.

And this is going to be my last question.

And this time my answer, it's going to be either yes, one of the rock types or no, one of the other rock types.

So let's just zoom in on the two rocks I have left.

They are conglomerate, which is the one at the top and granite, the one at the bottom.

What question could I ask to differentiate these two rocks to tell the difference between them? Maybe something like, does it have chunks of other rock in it? If the answer is yes, then it would be conglomerate.

If it's no, then it would be granite.

Now you could ask different questions in your key.

These are just examples of them.

A different question I could have asked here was, is it speckled? And if the answer is yes, then it would have been granite and no, then it would have been conglomerate, okay? There are different options.

So now we've got our four questions.

Is the rock white? Is it smooth? Is it stripy? Does it have chunks of other rock in it? So we've planned our key.

Can you please pause the video and write down our four questions with the numbers? So one, is the rock white? So you've got them as notes to the side for when you draw your key.

Pause the video and do that for me now.


Okay, so now we're ready to draw our key.

You're going to need a fresh piece of paper 'cause your key is going to take up your whole page and you're going to need your pencil and your ruler.

It's really important that when you're drawing your key those branches between the lines you're using a ruler so that your key is really neat and easy to read.

I'm going to show you on the screen what each step will look like.

So, the first thing you're going to do is you're going to write the question, is the rock white? In the top left hand corner of your page like I've done on my screen.

Imagine that my screen is your page.

You're going to underline it.

And then you're going to draw two branches.

One to yes and one to no.

Your yes and no don't have to be in a box, you can just write them neatly.

Can you pause the video and do that for me now? Fantastic.

Then underneath yes, you are going to write marble.

You might want to do that in a different colour to make it clear that that's your answer, that's your rock.

Pause the video and do that now.


Then from your next question, you're going to draw, sorry from no, you're going to write your next question which is, is it smooth? And underline it.

Pause the video and do that now.


So we're going to take you step by step and so many lots of pausing.

So you pause each time to make sure that you're doing this neatly.

Then from smooth you're going to get your ruler and you're going to draw your two options, no and yes.

Check the way I've written them.

So I've gotten to no on the left and yes on the right.

Don't draw your lines too long because remember we've got four questions to fit in.

So each question should take up about a quarter of your page.

Pause the video and do that now.


Then underneath no, you're going to write your next question, is it stripy? And underneath yes, you're going to write the answer obsidian.

You could do this in a different colour if you want.

Pause the video and do that for me now.



From stripy, can you draw your two branches, yes and no? Check the order that I've done them in.

So I've got yes going that way and no going that way.

I'm stopping at each time so that my key doesn't go sshhh from one side of the page, it's kind of like branching evenly.

Pause the video and draw your yes and no branches now.

Great, okay.

So then we've got our answer niece, sorry, gneiss under yes, check the spelling of it.

G-N-E-I-S-S, you can do that in a different colour.

And then you've got your last question.

Does it have chunks of other rock in it? You can write that and then underline it.

Pause the video and do that for me now.


And then we have our last branch.

No and yes.

So you can pause the video and do that now.

And our last two answers, granite under no and conglomerate under yes.

So you can do those in a different colour.

Pause the video to finish off your key.

Fantastic! Well done for creating your own identification key.

I hope you're proud of all the work that you've done this lesson and you've enjoyed having a taste of being a geologist today.

Hopefully you'll get to identify real rocks.

Maybe you could take your identification key next time you go for a walk and see if you can identify any rocks in your local environment.

If you'd like to share your work on Twitter you can ask your parent or carer to share it with the #LearnwithOak.

Thank you so much for all your hard work today.

I hope you have a fantastic rest of your day and I'll see you back here for our next science lesson which is going to be a fun one.

We are going to use jelly beans to show how the rock cycle works.

Bye everybody.