Hello, my name's Mrs. Niven, and today, we're going to be looking at types of rocks as part of our unit on "Earth's resources" and what we go through in today's lesson.

You may have some experience though from your previous learning, but what we do today, will help us to better understand and answer that big question of how we can explain changes in the air, the oceans, and the land.

So by the end of today's lesson, you should be able to more confidently use features to classify rocks into the different groups and suggest the properties of each type of rock.

Now, throughout the lesson, I'll refer to some keywords, and these include sedimentary, igneous, metamorphic, porous, and non-porous.

Now the definitions for these keywords are given in sentence form on the next slide, and you may wish to pause the video here, so you could read through them or perhaps even make a note of them to refer back to you later on in this lesson or later on in your learning.

Now, today's lesson is broken into two parts.

First, we'll look at outlining the different types of rocks, and then we'll look at their different properties and possible uses of those different rocks.

So let's get started by looking at the different types of rocks.

Now the first thing we need to do is remember that rocks are mixtures of minerals and that minerals can become mixed up during different geological processes.

Now, it's these processes that will impact the type of rock that forms. For instance, granite contains the minerals of feldspar, quartz and micas, and through one particular geological process, this particular rock of granite will form.

But those same minerals that go through a different geological process could actually form the rock known as sandstone.

There are three main types of rock, sedimentary, igneous, and metamorphic.

Now, each type of rock is formed by a very particular geological process, and these processes leave their mark on the rocks as they form.

Now, because of that, rocks contain clues to help us identify what type of rock it actually is.

For instance, sedimentary rocks contain distinct grains that have been glued together by other minerals.

And if we use a hand lens to look more closely at a sedimentary rock, we might be able to distinguish those individual grains.

Moreover, because of the processes that are involved in making a sedimentary rock, most of these sedimentary rocks will show layers.

And some sedimentary rocks also contain other things, like pebbles, grit, fragments of other rocks.

They could contain shells and they could even contain fossils.

Now, there are many different examples of sedimentary rocks, but some common ones would include things like sandstone, limestone, coal, shale, mudstone, and even chalk.

Let's stop here for a quick check.

Which of the following are features of sedimentary rocks? Well done if you said a, c and d, b is incorrect because sedimentary rocks have distinct grains rather than crystals.

But very well done if you got at least one of those correct answers and incredibly well done if you manage to choose all three, that's a fantastic start to today's lesson, guys.

Keep it up.

Now, igneous rocks contain crystals that point in all directions, and because of that, it looks like the crystals in it are all jumbled up.

And the size of the crystals in these igneous rocks can generally indicate where that rock may have formed.

For instance, in this example, if we were to look at it quite closely, we'd notice it has small crystals and that would indicate to us that this igneous rock formed above ground.

Whereas another example might show large crystals and that would indicate that the igneous rock formed below ground.

Now, because igneous rocks can form both above and below ground, there are quite a lot of different examples of them.

And some common ones include things like granite or pumice, basalt, gabbro, and even obsidian, also known as volcanic glass.

Let's stop for a quick check.

True or false? Igneous rocks contain large and small grains.

Well done if you said false, but which of these statements best justifies that answer? Well done if you said, b, igneous rocks contain large or small crystals, not grains.

Very well done if you managed to get those correct guys, great job.

Now, metamorphic rock also contains crystals, just like igneous rocks, but the crystals in metamorphic rocks are mostly aligned.

That means that they line up.

So if we were to look at an example of metamorphic rock a little bit more closely, we'd be able to see those crystals rather than being all jumbled up like they are in igneous rocks, they form more these straight lines in our metamorphic rocks.

And because the crystals are mostly aligned or lined up, our metamorphic rocks also tend to show layers.

And we can see that in our example here on the left.

And if we look at another example, we can see these layers look a little bit more brittle like they might break a little bit more easily.

But we can see that in both of these examples, we've got clear layers that have formed because of these lined up crystals in each example.

Now, metamorphic rocks can vary quite significantly in the way that they appear to us, but some very common examples include things like slate, marble, gneiss, soapstone and schist.

Another quick check then.

True or false? Metamorphic rocks show layers.

Well done if you said true, but which of these statements best explains why? Well done if you said a, the crystals in metamorphic rocks are aligned.

Remember, metamorphic rocks contain crystals, not grains.

Very well done if you manage to get that correct.

Okay, let's move on to the first task of today's lesson.

In this first part, I'd like you to decide, which type of rock, sedimentary, igneous, or metamorphic best matches each description.

For some of these, you may have one rock that you want to put.

You may wish to put more than one rock, but I would definitely recommend you discuss your ideas with the people nearest you and then come back when you're ready to check your answers.

Okay, let's see how you got on.

So a, said that we had crystals and that they're mostly lined up, and those two features combined would indicate that you are describing a metamorphic rock.

If instead, we have grains that are glued together that would indicate a sedimentary rock.

If we have crystals that are shown in all different directions or jumbled up, that would indicate an igneous rock.

But if our sample shows layers, it could be sedimentary or a metamorphic rock.

So if we have a sample that is showing layers, we'll need to look at other features to decide whether or not, it should be classified as a sedimentary or metamorphic rock.

And if a sample contains fossils, then we could say quite confidently that it's a sedimentary rock.

Very, very well done if you manage to get those correct.

If not, you may wish to consider going back to correct your answers, so that you can use the features from this task in the next one.

So for this next part of this task, I would like us to do a little bit of a practical.

I would like you to try to decide, which group of rocks or type of rocks each rock belongs to.

And in order to do that, you're going to need a selection of rocks and a magnifying glass or a hand lens of some kind.

Now what you're going to do is you're going to collect one of these rocks and hopefully, it's been labelled.

And what you'll need to do then is examine the rock very carefully with this magnifying glass.

And in a table, which I'll show you in a moment, you want to record any features that you notice about that rock.

Once you're done with that, you're going to use the features that you've noted to classify the rock then as being either sedimentary, igneous or metamorphic, and you're going to record that classification in your table.

Once you've done that for one rock, you're going to replace it, collect another rock, and repeat those steps from 1 to 4 for the rest of the rocks that you have in your selection.

Now, if you don't have any samples of rocks to hand, don't worry.

On the next slide, I have some examples that you can use for your own classification.

But before we get to that, let's just show you really quickly the table that you'll be using for your recording of your features and the classification of each rock.

So as you're going through your features and the type of rock, this is how you would want to use your table.

So labelling your rocks, what features will go under the observations, and then what type of rock you think will go into the final column.

Now, again, I said if you don't have samples of rock at hand, don't worry.

I will give you some examples on the next slide for you to use.

So if you don't have any samples, hold on.

If you do have your own samples of rocks to examine, then you may pause the video here and come back when you are ready to check your work.

If you need the samples, just a moment and I will show you them now.

So take some time now to look at these samples, record them.

They've already got labelled in your table of results from a to f, what observations can you make about these particular rock samples and what type of rock then do you think those features indicate it is? So pause the video and come back when you're ready to check your answers.

Okay, let's see how you got on.

Now, if you had your own rock samples, obviously, they're not going to match the ones that I have here.

You'll have your own observations and then you'll need to decide what type of rock it is.

But what I would recommend you do looking through these if you've used your own samples, is what observations did we look for and how did we then interpret those observations to decide the type of rock we might have? Now, if you use the samples that I provided, those are the one I'm going to to talk about how we might use these observations and classify it.

So for part a or rock sample a, sorry, I can observe quite clearly that it contains a fossil and it's a quick and easy thing to observe.

And because of that, I can quite confidently say that it is a sedimentary rock, b is a little bit trickier.

I can definitely see layers in it and it might contain crystals.

Now, I say might, and that's why I've put a question mark 'cause I wasn't quite sure, but because I was thinking it has crystals and we have layers, those two features combined make me think that it might be a metamorphic rock.

Whereas, c, looks like there's no layers whatsoever and it might contain some very small crystals.

Now, because it doesn't contain any layers whatsoever, I think this might be an igneous rock.

Now, d shows layers as well, but I think this time it contains grains and because of that it will be a sedimentary rock, e, again shows no layers and looks to contain large crystals in many directions, so I would say igneous rock.

And f was really tricky.

I think it shows layers 'cause if you look towards the bottom of that image, it does look to have quite thin layers and it might contain grains, so it could be a sedimentary rock.

That was a really tricky one for me to try and classify.

And that's the thing with rocks.

Sometimes, it can be a little tricky.

Very, very well done if you've managed to record some observations for your rocks and then use those to then classify your rock samples as sedimentary, metamorphic or igneous.

Very, very well done applying what we've learned to different rocks in front of you.

Great job, guys.

Now for the last part of this task, I'd like you to reflect on what you've just done.

So Task A, part 2 and I want you to answer the following questions.

Which type of rock do you think is easiest to identify? And I'd like you to explain your answers.

So I'm looking for that because clause, explaining why.

For part b, then I'd like you to tell me, which two rocks do you think are the hardest to tell apart.

And again, include that because clause.

Explain why you think those two are so hard to distinguish between.

You may wish to discuss your ideas with the people nearest you.

So pause the video and then come back when you're ready to check your work.

Okay, let's see how you got on.

Now, whenever you're being asked to reflect on something, it is going to be a very personal answer to it, and that's one of the reasons why an explanation for your reflection is so important because somebody might not agree with you and that's fine.

But we do need you to support your reasoning here.

So what I would say is your answers may be similar to these, they may not.

But as long as you have that supporting because clause, then you are doing an excellent job.

For me, the easiest type of rock to identify was actually sedimentary rocks.

And that's because they can have very distinct grains, but there's lots of other features I could look for.

It might contain fragrance of shells, it might contain fossils, it contains layers, it can contain pebbles of some sort.

So there's lots of things to look for to indicate a sedimentary rock.

The rocks that I think were very difficult to distinguish between was actually igneous and metamorphic because the crystals is sometimes really hard to see, even if you have a magnifying glass or a hand lens.

And it can sometimes be really hard to see if the crystals are lined up in layers or not, especially if those crystals are very, very small.

So those are the ones that I really struggled with.

I wonder if maybe you had a similar difficulty, but it's okay if you had different ideas of which rocks were easy or hard to identify, as long as you were able to explain why you had those difficulties, 'cause then maybe we can work together to come up with strategies that make it easier for you to identify these rocks going forward.

But very, very well done on this task, guys.

I'm so impressed with the work you're doing.

Keep it up.

Now that we're feeling more comfortable distinguishing between different types of rocks, let's look at their different properties and uses.

Now, if you recall, sedimentary rock contains grains that have been glued together by other minerals.

Now, sedimentary rocks also tend to contain small spaces between those grains, and these are called pores.

Now, rocks that contain pores are described as being porous.

And when a porous rock is put into water, any air that might have existed within that gap, that pore is pushed out, it's displaced from it.

And we can see that by looking very, very carefully at the surface of a rock when it's been placed into that water.

For instance, a sedimentary rock doesn't normally look like it has gaps between the grains, but when it's put into that water, we can see that displaced air, that air that's been pushed out of the pores as a bubble on the surface of that rock.

And that's really significant because porous rocks are able to absorb and hold air, water, and other liquids because it has the space for it in those gaps.

Now, sedimentary rocks are usually porous and porous rocks tend to scratch easily.

So if we take an example of a sedimentary rock, here we are using sandstone and we scrape a nail across its surface, it's left a mark.

We can see that scratch, okay? Now that indicates that these porous rocks also tend to be quite soft or softer than other rocks, and they're gonna be prone to crumbling and breaking, and that can have a big impact when we look at sedimentary rocks on a large scale, as we can see here with this sandstone cliff.

Now, despite being porous, sedimentary rocks have been used for sculptures for thousands of years.

For instance, the largest sarsen stones at Stonehenge are hardened sandstone, and the UNESCO World Heritage Site of Petra was carved from sandstone.

Let's stop here for a quick check.

Which of the following correctly describes the properties of sedimentary rock? Well done if you said, a, b and d, all of those describe a sedimentary rock.

Don't worry if you didn't get all of them, but well done if you got at least one or two of those, you are starting to link up our understanding of sedimentary rocks and those properties related to them.

So great, great job guys.

Keep it up.

Now, rocks then that don't contain any gaps between the grains or the crystals are described as being non-porous.

And most igneous and metamorphic rocks are described as non-porous because those crystals interlock and they lock together a bit like a mosaic.

And if you recall how we showed those crystals earlier, this is a reminder.

So we can see that there aren't any clear gaps between these crystals in our igneous and metamorphic rock.

Now, because non-porous rocks don't have any pores or gaps between them, they're unable to hold air, water, or other liquids in them.

So if we were to put a non-porous rock into water, we wouldn't see any air displaced.

We wouldn't see any bubbles on its surface.

Moreover, non-porous rocks tend to scratch less easily.

They're stronger than the porous rocks.

So if we were to take a nail, scrape it along the surface of our non-porous rock, we wouldn't be able to see any visible scratches on it.

Now these properties of igneous and metamorphic rocks make them suitable for a lot of different purposes, including buildings, roofing, steps, even making mortar and pestles and significantly fine detailed sculptures.

Another quick check then.

True or false? Igneous and metamorphic rocks tend to be non-porous.

Well done if you said true, but which of these statements best justifies why? Well done if you said, b.

Non-porous rocks contain interlocking grains.

Very, very well done, guys.

You're doing supremely well.

Now, the properties of rock, like if it's porous or non-porous, if it's going to scratch easily or not, are all very good considerations to think about when we are deciding about which type of rock to use for a specific purpose.

But there are other considerations, we need to also look at before deciding on that final type of rock to use.

And these things might include how easy is it to source this rock? How easy is it to get or obtain? How much is it going to cost to obtain this rock? Is it one that's very easy to find or maybe not? Is it far away or is it close by? How heavy is this rock, for instance, is that going to make it more difficult to move or is support going to be needed to keep it in place? Is this rock going to break or shatter if it's hammered, for instance, when you are creating a sculpture or something and will this rock actually be used for a specific purpose for a function, or is it purely for decoration? Let's move on now to the last task in today's lesson.

For this first part, I'd like you to match the keywords to the most appropriate description.

So pause the video and then come back when you're ready to check your work.

Let's see how you got on then.

So sedimentary should be matched up to described as porous.

Non-porous describes a rock with interlocking grains or crystals.

Igneous is examples including pumice or granite.

Porous describes a rock with gaps between its grains.

And metamorphic is a type of rock with examples that include marble and slate.

So very, very well done if you manage to match those correctly, guys.

For the second part of this task, some pupils are discussing, which rock would be the most appropriate one to use for a kitchen worktop.

So what I'd like you to do is to read the statements on the next slide and then answer the questions.

So when selecting a rock to use, the function of this worktop is an important factor.

So which pupil's statement best considers this factor? And I'd like you to explain your reasoning.

So I'm looking for a because clause to support your choice.

Now, Alex thinks that slate will be the best rock to use for a kitchen worktop because it naturally forms flat surfaces.

Izzy reckons that sandstone would be the best because it's easy to get.

And Andeep reckons that granite would be the best because granite is non-porous.

So you may wish to pause the video here, so you can discuss your ideas with the people nearest to you and then come back when you're ready to check your answers.

Okay, let's see how you got on.

I personally would have thought that Andeep had the best suggestion because he chose a rock that was non-porous.

Now, non-porous rocks won't hold or absorb any liquids or odours.

So use in a kitchen like that would be absolutely fantastic.

We don't want these liquids or odours being absorbed and held in that worktop.

It would really start to stink after a while.

The other thing about granite is that it's also quite hard, so it's not gonna scratch very easily if something is chopped on top of it.

So it's an excellent, excellent choice for the function of this worktop.

So well done if you chose Andeep.

So now that we know that Andeep's suggestion would work best for a kitchen worktop, why do you think Alex and Izzy's suggestions are perhaps less appropriate for this kitchen worktop? So pause the video and then come back when you're ready to check your answers.

Now, when we look more closely at Alex's suggestion of slate, it's not necessarily a bad idea because the flat surface that slate forms would be quite useful as a worktop.

However, slate chips really easily and because of that it would be unsuitable in a kitchen because as you're chopping things, you might end up with sharp edges, and that's definitely not something we want.

And if it is chipping, we don't want it in our food either.

Now is a suggestion of sandstone is focusing more on the ease of sourcing that rock rather than its intended final use within the kitchen.

And the other thing we need to remember about sandstone is that it's porous and it's prone to crumbling.

So the sandstone would be able to absorb and hold onto those odours or liquids that might be able to get into it in the kitchen.

And when you are cutting anything on the surface, it could actually crumble that worktop quite quickly.

So very well done if you managed to identify any of the reasons why these suggestions from Alex and Izzy may be are less appropriate, than Andeep's suggestion of granite.

'Cause you're really starting to think about many different features about these rocks that would impact how it might be used.

So very, very well done on a tricky task, guys.

I'm so impressed with what you've managed to do today.

Wow, we've gone through a lot of information in today's lesson.

So let's take a moment to summarise what we've learned.

Well, we've learned that sedimentary rocks are those that contain distinct grains stuck together with different minerals, and that they could contain lots of different things, including fragments of shells, fossils, larger pieces of grit or even pebbles.

Igneous rocks, on the other hand, can form both above and below ground.

And that these rocks contain crystals that point in all directions, so they're all jumbled up.

Metamorphic rocks then also contain crystals.

However, these crystals are aligned or line up forming layers.

And that sedimentary rocks are usually porous, meaning that they have gaps between the grains, whereas the igneous and metamorphic rocks tend to be non-porous because they don't have any gaps between those crystals.

And finally, we've learned that properties of rocks can influence what they're finally used for.

I've had a really good time learning with you today.

I hope you've had a good time learning with me, and I hope to see you again soon.

Bye for now!.