0:00:03 > 0:00:07# There are lots of things All around us
0:00:07 > 0:00:10# Exciting things That surround us
0:00:10 > 0:00:12# But how does it work?
0:00:12 > 0:00:13# Do you know?
0:00:13 > 0:00:15# How is it made?
0:00:15 > 0:00:17# Do you know?
0:00:17 > 0:00:20# Things that go up Things that go down
0:00:20 > 0:00:23# Things that go pop! Things that go round
0:00:23 > 0:00:27# With special cameras To show you inside
0:00:27 > 0:00:30# It's going to be a big surprise
0:00:30 > 0:00:32# But how does it work?
0:00:32 > 0:00:34# Do you know?
0:00:34 > 0:00:35# How is it made?
0:00:35 > 0:00:37# Do you know?
0:00:37 > 0:00:39# Do you know?
0:00:39 > 0:00:40# Let's find out! #
0:00:42 > 0:00:46Hello, I'm Maddie, and today I'm on a building site.
0:00:46 > 0:00:50Just think, the house or flat where you live once started off like this!
0:00:50 > 0:00:54A great big pile of bricks and wood ready to be made into a building.
0:00:57 > 0:01:01You should never go onto a building site without a grown-up,
0:01:01 > 0:01:06but we've got special permission to show you something really exciting.
0:01:06 > 0:01:11A lot of the things used to make houses are very heavy!
0:01:11 > 0:01:13Far too heavy for me to pick up.
0:01:13 > 0:01:16So, I need something super clever to help me.
0:01:21 > 0:01:25Can you guess what it is?
0:01:25 > 0:01:26A crane!
0:01:26 > 0:01:30A crane is the safest way to move things around that are too heavy
0:01:30 > 0:01:33for people to pick up.
0:01:33 > 0:01:37But do you know how a crane works?
0:01:37 > 0:01:38Let's find out.
0:01:44 > 0:01:49Before the crane can do anything, it needs to stand on its own feet.
0:01:51 > 0:01:53You should never play around vehicles.
0:01:53 > 0:01:57Always make sure you're near a grown-up.
0:01:58 > 0:02:02These special feet keep the crane steady when it picks up
0:02:02 > 0:02:04heavy things, and stops it rolling away.
0:02:04 > 0:02:08Look how it's lifting the wheels off the ground.
0:02:08 > 0:02:11The place where the driver sits is called the cab.
0:02:11 > 0:02:15In here, there are lots of levers he uses with his hands,
0:02:15 > 0:02:18and pedals, which he moves with his feet.
0:02:25 > 0:02:29The levers are connected to the big arm, and when the driver
0:02:29 > 0:02:33moves the levers, this big arm moves across the sky.
0:02:35 > 0:02:38It's called the boom, and look!
0:02:38 > 0:02:40It gets longer, too!
0:02:45 > 0:02:49The boom gets longer and shorter in the same way my telescope works.
0:02:50 > 0:02:53The first part of my telescope is slightly thinner than
0:02:53 > 0:02:55the second part.
0:02:55 > 0:02:59So, this means the first part can move easily in and out.
0:02:59 > 0:03:02Meaning the telescope can get longer or shorter,
0:03:02 > 0:03:05just like the boom on the crane.
0:03:05 > 0:03:09So, we've seen how the driver uses the levers to move the boom
0:03:09 > 0:03:12around, but how does the boom get longer and shorter,
0:03:12 > 0:03:15and move higher into the sky?
0:03:15 > 0:03:18To find out, we need to take a closer look.
0:03:18 > 0:03:22BEEP-BEEP! Here comes the crane.
0:03:22 > 0:03:24And there's the boom.
0:03:24 > 0:03:27To make the crane get longer and higher, there are special
0:03:27 > 0:03:31tubes called hydraulic cylinders underneath the boom.
0:03:31 > 0:03:34The tubes are full of water and oil.
0:03:34 > 0:03:36When a button is pressed in the cab,
0:03:36 > 0:03:40the water and oil are pumped upwards inside the tube.
0:03:40 > 0:03:44They have nowhere to go, and so this pushes the boom up.
0:03:44 > 0:03:49There are also hydraulic cylinders inside the boom.
0:03:49 > 0:03:51When another button is pushed,
0:03:51 > 0:03:55the water and oil inside these cylinders are pumped up too.
0:03:55 > 0:03:57This pushes the boom out, making it longer.
0:03:59 > 0:04:03But do you know how the crane picks things up?
0:04:03 > 0:04:05Different things can be attached to the end
0:04:05 > 0:04:09of the boom to pick things up in all sorts of ways.
0:04:09 > 0:04:11A fork, to lift things up from the bottom.
0:04:12 > 0:04:16Or a grabber to grab hold of things, like a great big hand.
0:04:16 > 0:04:20Or, a chain, to pick things up from the top.
0:04:22 > 0:04:26There's something on the end of this boom. Do you know what this is?
0:04:26 > 0:04:28That's right, it's called a hook.
0:04:28 > 0:04:33And the crane uses the hook to hook onto things to pick them up.
0:04:33 > 0:04:34It's clever, isn't it?
0:04:34 > 0:04:38I've got my special camera with me, and I'm going to put it on
0:04:38 > 0:04:43the hook so we can see what it looks like from high up on the crane.
0:04:48 > 0:04:51And we have lift-off!
0:04:51 > 0:04:56The special camera is moving higher into the air.
0:04:57 > 0:04:59Hello!
0:04:59 > 0:05:00SHE LAUGHS
0:05:00 > 0:05:04The special camera can see so much from way up high.
0:05:06 > 0:05:10It's still going, higher and higher.
0:05:10 > 0:05:13I can't believe it! I look as small as an ant!
0:05:15 > 0:05:17That is so high!
0:05:18 > 0:05:21Should we bring it back down again?
0:05:23 > 0:05:25Hello, camera!
0:05:25 > 0:05:27How brilliant was that?
0:05:27 > 0:05:32But we want the crane to move this great big pile of wood onto
0:05:32 > 0:05:34the back of that truck.
0:05:34 > 0:05:36Let's see how it does it.
0:05:38 > 0:05:41Up goes the boom. Listen to the sound it makes...
0:05:41 > 0:05:44WHEEOO-OO
0:05:44 > 0:05:47It's like an aeroplane taking off!
0:05:48 > 0:05:52That's the hydraulic cylinders pushing the boom arm up
0:05:52 > 0:05:53into the sky.
0:05:54 > 0:05:58Once the boom is in the right position, some special chains
0:05:58 > 0:06:01are wrapped around the wood, and attached to the hook.
0:06:07 > 0:06:09Up we go, Paul!
0:06:15 > 0:06:19The chains are on, and the boom is about to lift up that pile of wood!
0:06:21 > 0:06:24It's a bit like a game of hook the duck, isn't it?
0:06:24 > 0:06:26And have you played that before?
0:06:26 > 0:06:31That pile of wood weighs the same as a family car, but it's
0:06:31 > 0:06:33no problem for the crane, is it?
0:06:35 > 0:06:39The boom is moving across in the sky to make sure the wood is in
0:06:39 > 0:06:44the right position, and then it will lower it down onto the truck.
0:06:47 > 0:06:49Brilliant!
0:06:50 > 0:06:54What was your favourite bit about seeing how a crane works?
0:06:55 > 0:07:00Can you remember the name of the big arm that the driver controls?
0:07:00 > 0:07:03That's right - it's called the boom.
0:07:03 > 0:07:07Did you like the sound the hydraulic cylinder made as it
0:07:07 > 0:07:09pushed to boom up into the sky?
0:07:09 > 0:07:12WHEEOO-OO
0:07:14 > 0:07:18And did you see how high up the crane went with my special camera?
0:07:18 > 0:07:20That is so high!
0:07:25 > 0:07:29There are lots of things that cranes can move. There's...wood.
0:07:31 > 0:07:34And these - bricks.
0:07:34 > 0:07:38Most houses and buildings are made with lots of bricks.
0:07:38 > 0:07:41The bricks are built into walls that hold up the roof
0:07:41 > 0:07:46and keep out the rain and wind, helping us to stay warm and safe.
0:07:46 > 0:07:51They have to be very strong, and last a long time.
0:07:51 > 0:07:55But do you know how bricks are made?
0:07:55 > 0:07:57Let's go and find out.
0:08:01 > 0:08:05Well, to make a brick you have to start off in a place like this.
0:08:05 > 0:08:09It's called...a quarry!
0:08:09 > 0:08:12A quarry is a place where we dig in the ground for things
0:08:12 > 0:08:14like rock or sand.
0:08:14 > 0:08:19This digger is digging for something used to make bricks - clay.
0:08:22 > 0:08:24This is clay.
0:08:24 > 0:08:27It's found underground and it's full of water,
0:08:27 > 0:08:30which makes it all squishy!
0:08:30 > 0:08:32Just listen to the sound.
0:08:32 > 0:08:35SQUELCH!
0:08:35 > 0:08:39All squelchy and soft.
0:08:39 > 0:08:42Clay can be squished into all sorts of shapes,
0:08:42 > 0:08:46and it's used to make lots of different things. Clay makes...
0:08:46 > 0:08:51dinner plates, plant pots, you might have even used clay yourself.
0:08:51 > 0:08:54Look, I've turned some clay into a little man!
0:08:56 > 0:09:00As well as clay, bricks are made from this - sand.
0:09:00 > 0:09:03Sand is really strong and is made from rocks that are
0:09:03 > 0:09:06crushed into tiny, tiny bits.
0:09:06 > 0:09:09Now, if you've ever built a sandcastle, then you'll know
0:09:09 > 0:09:13just how good sand is for building things.
0:09:13 > 0:09:17The sand is mixed with the clay, and these tiny black things.
0:09:18 > 0:09:21Do you know what this is?
0:09:21 > 0:09:23It's called coal.
0:09:23 > 0:09:28Coal is made from trees and plants that died millions of years ago.
0:09:28 > 0:09:31And, over time, it's turned black.
0:09:31 > 0:09:34And now it's more like a rock than plants.
0:09:34 > 0:09:36Isn't that amazing?
0:09:37 > 0:09:40Now, let's going see how the clay, the sand,
0:09:40 > 0:09:42and the coal are all mixed together.
0:09:42 > 0:09:43Come and look.
0:09:45 > 0:09:47Wow! Oh!
0:09:53 > 0:09:57The clay, sand and coal is being mixed inside this huge drum.
0:09:57 > 0:09:59But I want to get a closer look.
0:09:59 > 0:10:03Luckily, I've got my special camera with me, on a long pole,
0:10:03 > 0:10:07so we can get right inside the mixer and see what's going on.
0:10:12 > 0:10:16Wow! That's brilliant!
0:10:17 > 0:10:21The two big wheels inside the drum are spinning round
0:10:21 > 0:10:25to really crush up the sand, the clay and the coal.
0:10:25 > 0:10:27To mix it together.
0:10:32 > 0:10:33When the mix is ready,
0:10:33 > 0:10:37it goes along a special moving shelf called a conveyer belt.
0:10:37 > 0:10:42It travels through the factory and then it goes through this machine,
0:10:42 > 0:10:47oozes onto the table, where John can turn it into a brick.
0:10:51 > 0:10:53John uses a special box like this.
0:10:53 > 0:10:58It's called a mould, and it's the shape of a brick.
0:10:58 > 0:11:00John puts in a dollop of the mixture,
0:11:00 > 0:11:03which he flattens with a piece of wood.
0:11:04 > 0:11:08He then turns the mould over, and out comes a brick.
0:11:10 > 0:11:13The problem is, even though the mixture looks like a brick,
0:11:13 > 0:11:17it's still soft and squidgy!
0:11:18 > 0:11:22And you can't build a house with a brick like that!
0:11:22 > 0:11:26Do you know how we could make the brick dry and turn hard?
0:11:29 > 0:11:32The bricks are put in a special place called a kiln to dry.
0:11:33 > 0:11:38They will have to be in there for three whole days!
0:11:38 > 0:11:43The bricks are now dry, but they're not very strong or hard.
0:11:43 > 0:11:47They're still a little bit...crumbly.
0:11:47 > 0:11:50To become hard enough to be built into houses,
0:11:50 > 0:11:52they have to be cooked in an oven.
0:11:55 > 0:11:59This is called firing, and it's really noisy!
0:12:01 > 0:12:03Can you see that the bricks have turned yellow?
0:12:03 > 0:12:08This means that they're very, very hot.
0:12:10 > 0:12:13The bricks are fired for another three days.
0:12:16 > 0:12:20Firing the bricks makes the clay dry out even more,
0:12:20 > 0:12:24so they become really hard.
0:12:24 > 0:12:26And these are finished bricks.
0:12:26 > 0:12:28KNOCK KNOCK KNOCK!
0:12:28 > 0:12:32Ho-ho-ho! Wow! I can't believe how much they've changed.
0:12:32 > 0:12:35They're not soft and squishy any more.
0:12:35 > 0:12:37Now, they're really, really hard!
0:12:37 > 0:12:40And, I think, ready to build a house with.
0:12:40 > 0:12:42KNOCK!
0:12:43 > 0:12:47I loved seeing how bricks were made. Did you?
0:12:47 > 0:12:50What was your favourite bit?
0:12:50 > 0:12:54Can you remember the name of the special boxes the clay and
0:12:54 > 0:12:56sand mixture was put into?
0:12:56 > 0:13:00That's right, they're called moulds, and they give the bricks
0:13:00 > 0:13:01their special shape.
0:13:01 > 0:13:05Did you like the sound of the sloppy clay squelching in my hands?
0:13:05 > 0:13:08SQUELCH!
0:13:09 > 0:13:13And did you see how the bricks got so hot in the kiln that they
0:13:13 > 0:13:15turned yellow?
0:13:21 > 0:13:24So, the next time you're in your house, you'll know how
0:13:24 > 0:13:28the bricks were made, and how the big cranes were used
0:13:28 > 0:13:30to move them all about. See you next time.
0:13:33 > 0:13:34# There are lots of things
0:13:34 > 0:13:36# All around us
0:13:36 > 0:13:38# Exciting things
0:13:38 > 0:13:39# That surround us
0:13:39 > 0:13:41# But how does it work?
0:13:41 > 0:13:43# Do you know?
0:13:43 > 0:13:45# How is it made?
0:13:45 > 0:13:46# Do you know?
0:13:46 > 0:13:48# Do you know?
0:13:48 > 0:13:50# Let's find out! #