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 > 0:00:13- #- But how does it work?- Do you know?
0:00:13 > 0:00:17- #- How is it made?- 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 > 0:00:34- #- But how does it work?- Do you know?
0:00:34 > 0:00:37- #- How is it made?- Do you know?
0:00:37 > 0:00:40- # Do you know?- Let's find out!- #
0:00:42 > 0:00:45Hello, I'm Maddie, and it's bath time.
0:00:45 > 0:00:48And I'm just about to run a bath.
0:00:48 > 0:00:50Let's pop the plug in
0:00:50 > 0:00:52and turn on the tap.
0:00:54 > 0:00:59I love bath time. Do you? What do you like most about it?
0:00:59 > 0:01:00Is it...
0:01:01 > 0:01:03..the rubber ducks?
0:01:03 > 0:01:04QUACK QUACK!
0:01:04 > 0:01:06Or the bubbles?
0:01:06 > 0:01:09I love a bubble bath, so,
0:01:09 > 0:01:13I'm going to pour in a nice big dollop of bath foam.
0:01:16 > 0:01:20Remember, you must always get a grown-up to run your bath.
0:01:20 > 0:01:22Listen to the sound.
0:01:22 > 0:01:24Swish, swish, swish.
0:01:25 > 0:01:28And now we have lots of lovely bubbles.
0:01:31 > 0:01:32QUACK QUACK!
0:01:33 > 0:01:36What else do you like about bath time?
0:01:36 > 0:01:40I like that the water is nice and warm.
0:01:40 > 0:01:44But do you know where the water comes from?
0:01:44 > 0:01:48How does it get into the taps and how does your bathwater get warm?
0:01:48 > 0:01:50How does hot water work?
0:01:50 > 0:01:52Let's go and find out.
0:01:58 > 0:02:03Your bathwater starts its journey here,
0:02:03 > 0:02:05in a reservoir.
0:02:05 > 0:02:09A reservoir is a big lake that's used to store water.
0:02:09 > 0:02:13The water collected here will come from rivers and streams,
0:02:13 > 0:02:16and also the rain.
0:02:16 > 0:02:20All the water that is collected here in the reservoir is cleaned,
0:02:20 > 0:02:22so that it's safe.
0:02:22 > 0:02:27And then it's sent through pipes to our houses.
0:02:27 > 0:02:30There are lots of pipes under the roads and pavements
0:02:30 > 0:02:34where you live, and some of these big pipes carry water
0:02:34 > 0:02:37all the way from the reservoir into your house.
0:02:37 > 0:02:41In your bathroom at home, you might have a sink and a tap just
0:02:41 > 0:02:46like this one, and to get water all you need to do is turn the tap on.
0:02:46 > 0:02:47Amazing, isn't it?
0:02:47 > 0:02:51But the water that comes from the reservoir is cold,
0:02:51 > 0:02:54so...how does it get hot?
0:02:56 > 0:02:59To make the water hot, we need one of these,
0:02:59 > 0:03:00a boiler.
0:03:00 > 0:03:03There are lots of different types of boiler,
0:03:03 > 0:03:05and you might have one in your house.
0:03:05 > 0:03:09Let's find out how this one makes the water hot.
0:03:10 > 0:03:15The water from a reservoir goes through a building to be cleaned.
0:03:15 > 0:03:18It's then sent by pipes to our homes.
0:03:19 > 0:03:24One of the ways cold water is heated in your house is by a boiler.
0:03:25 > 0:03:28Inside the boiler is a small tank.
0:03:28 > 0:03:33The water gets heated there by a row of flames or electricity.
0:03:33 > 0:03:37When it's hot, the water is sent out through another pipe
0:03:37 > 0:03:39to a much bigger tank.
0:03:39 > 0:03:42This big tank is called a cylinder.
0:03:42 > 0:03:45Inside it, there is a big heated coil,
0:03:45 > 0:03:49which keeps all the water warm until you want to use it.
0:03:50 > 0:03:52When you turn the hot water tap on,
0:03:52 > 0:03:58it lets water from the cylinder tank travel along the pipe,
0:03:58 > 0:04:01into the tap and out into your bathtub.
0:04:01 > 0:04:05WATER BUBBLES
0:04:05 > 0:04:07QUACK QUACK!
0:04:07 > 0:04:10Aww, it's lovely and warm.
0:04:10 > 0:04:13But remember, it's important that a grown-up always checks
0:04:13 > 0:04:16how hot the water is before you get in the bath.
0:04:16 > 0:04:21To see how hot the bathwater is, I've got a special camera.
0:04:21 > 0:04:25This is called a thermal camera, and it tells us
0:04:25 > 0:04:29what's hot and what's cold by showing us different colours.
0:04:29 > 0:04:30Ooh, hello everyone!
0:04:31 > 0:04:34What colours can you see?
0:04:34 > 0:04:39Blue things are cold and red things are warm.
0:04:39 > 0:04:43So, look, can you see just how red my face is?
0:04:43 > 0:04:46And that's because the inside of my body is warm.
0:04:46 > 0:04:49What about the inside of my mouth?
0:04:49 > 0:04:52SHE BREATHES OUT Whoa!
0:04:52 > 0:04:55It's so hot that it's white.
0:04:55 > 0:04:58Let's have a look down at the floor, shall we?
0:04:58 > 0:05:04My feet are bright red because my feet are warm, apart from my toes.
0:05:04 > 0:05:06My toes are freezing.
0:05:06 > 0:05:09SHE LAUGHS
0:05:09 > 0:05:13But if cold things are blue and hot things are red,
0:05:13 > 0:05:17do you know what colour the bath will be?
0:05:17 > 0:05:18Ohh!
0:05:18 > 0:05:21Wow, look at that!
0:05:21 > 0:05:25The bathwater is bright red and yellow,
0:05:25 > 0:05:27and that's because it's warm.
0:05:27 > 0:05:30In some places the water is even white,
0:05:30 > 0:05:32and that's where it's very hot.
0:05:32 > 0:05:38But can you see, the mountains of bubbles are blue?
0:05:38 > 0:05:42And that's because the bubbles are cooler than the water.
0:05:42 > 0:05:44You know what else is blue?
0:05:44 > 0:05:47QUACK QUACK! Our little rubber duck friends.
0:05:47 > 0:05:51Look at the blue duck, swimming around in the swirly red water.
0:05:51 > 0:05:55Let's turn on the cold water and see what happens.
0:05:55 > 0:05:57Whoa!
0:05:57 > 0:06:02It's really dark blue. The water must be freezing.
0:06:02 > 0:06:07Now let's see what happens when we turn the hot water on instead.
0:06:07 > 0:06:11Did you see the colour change as it went from cold water to hot water?
0:06:11 > 0:06:17The hot water is red and white, which means it's hot.
0:06:17 > 0:06:21And that's because the cold water has come from the reservoir,
0:06:21 > 0:06:25through the pipes under the roads and into your house.
0:06:25 > 0:06:29It's then gone to the boiler, where it's been heated up and kept warm
0:06:29 > 0:06:33in the cylinder tank, ready to go in the bath when I turn on the hot tap.
0:06:33 > 0:06:34Excellent.
0:06:36 > 0:06:41What was your favourite bit about finding out how hot water works?
0:06:41 > 0:06:45Do you remember what you call a lake that stores rainwater
0:06:45 > 0:06:47for us to use in our homes?
0:06:47 > 0:06:49Yes, it's a reservoir.
0:06:49 > 0:06:54Did you hear the sound the water made when I swished it in the bath?
0:06:54 > 0:06:57WATER SLOSHES
0:06:57 > 0:07:01And did you see how the thermal camera made hot things look red
0:07:01 > 0:07:03and cold things look blue?
0:07:10 > 0:07:14Now, after I have a bath, there is an important thing I have to do
0:07:14 > 0:07:17every night before I go to bed.
0:07:17 > 0:07:19Can you guess what it is?
0:07:19 > 0:07:21Yes! Brush my teeth.
0:07:21 > 0:07:23And to make my teeth squeaky clean,
0:07:23 > 0:07:26I have to brush them with toothpaste.
0:07:28 > 0:07:31My toothpaste is stripy.
0:07:31 > 0:07:35But do you know, how does toothpaste get its stripes?
0:07:35 > 0:07:37Let's go and find out.
0:07:43 > 0:07:46Your toothpaste is made in a big factory like this.
0:07:48 > 0:07:53This factory makes one million tubes of toothpaste every day.
0:07:53 > 0:07:56That's a lot of toothpaste.
0:07:56 > 0:07:59The toothpaste ingredients arrive at the factory
0:07:59 > 0:08:02in lorries like this one. It's called a tanker,
0:08:02 > 0:08:05and it looks a bit like a tube of toothpaste, doesn't it?
0:08:05 > 0:08:08This tanker is full of something called "silica"
0:08:08 > 0:08:10that looks like this, a white powder.
0:08:10 > 0:08:14It gets pushed through the tubes way up into the factory.
0:08:14 > 0:08:15Over to you!
0:08:22 > 0:08:24BEEP BEEP
0:08:24 > 0:08:27As well as silica, there are other ingredients to be used.
0:08:27 > 0:08:30And they have quite complicated names like,
0:08:30 > 0:08:34"xanthan gum" or "trisodium citrate dihydrate".
0:08:35 > 0:08:37Try saying that quickly.
0:08:37 > 0:08:40The first thing is they're all taken to a giant mixer.
0:08:40 > 0:08:42BEEP BEEP
0:08:42 > 0:08:44And this is it.
0:08:44 > 0:08:48All of the ingredients are mixed in this giant tank,
0:08:48 > 0:08:51to make a paste that we call toothpaste.
0:08:52 > 0:08:55But it's not quite ready yet.
0:08:56 > 0:09:00Can you remember what my favourite type of toothpaste was?
0:09:00 > 0:09:03Yes, it's stripy toothpaste.
0:09:03 > 0:09:08So, do you know how toothpaste gets its stripes?
0:09:08 > 0:09:11Well, for the stripes we need to add colour.
0:09:11 > 0:09:16Red and blue, but you only need to add a very little bit.
0:09:16 > 0:09:19Can you believe that this much blue dye would be enough
0:09:19 > 0:09:24for 50,000 tubes of toothpaste?
0:09:24 > 0:09:28That's enough toothpaste for a tube for every single person
0:09:28 > 0:09:31in a packed-out football stadium.
0:09:31 > 0:09:33Wow.
0:09:34 > 0:09:37The toothpaste travels from the mixture,
0:09:37 > 0:09:41all the way along these pipes into these big silver pots,
0:09:41 > 0:09:44where some of the toothpaste gets its colour.
0:09:44 > 0:09:46We have red and blue, and look,
0:09:46 > 0:09:50you can even see some of the red and blue dye around the machine.
0:09:50 > 0:09:54Once the colour has been added, all the toothpaste gets pushed
0:09:54 > 0:09:58through these pipes that go down into the floor.
0:09:58 > 0:10:01Where do you think it goes next?
0:10:01 > 0:10:06It comes through the ceiling to the floor below through these pipes.
0:10:06 > 0:10:11One pipe is carrying red toothpaste, the other, blue toothpaste,
0:10:11 > 0:10:13and the last one, white toothpaste.
0:10:13 > 0:10:17The toothpaste is checked to make sure it's properly mixed,
0:10:17 > 0:10:19so, some of it is brought here to be tested.
0:10:21 > 0:10:24Uhhhh, ha-ha!
0:10:24 > 0:10:28Look at all this gloopy toothpaste.
0:10:28 > 0:10:31Have you ever seen so much in one place?
0:10:31 > 0:10:32Looks a bit like ice cream.
0:10:32 > 0:10:36But what about our stripy toothpaste?
0:10:38 > 0:10:40Look at all these empty tubes.
0:10:40 > 0:10:45They travel through this machine, where they get flipped upside down,
0:10:45 > 0:10:48ready to be filled with our stripy toothpaste.
0:10:51 > 0:10:57This super-fast machine is putting the toothpaste inside the tubes.
0:10:57 > 0:11:01Inside these pipes, the three colours of toothpaste - white,
0:11:01 > 0:11:04red and blue, are being pushed into the tubes.
0:11:04 > 0:11:07Can you see the stripes?
0:11:07 > 0:11:10This is one of the pipes that fill the toothpaste tubes
0:11:10 > 0:11:11inside the machine.
0:11:11 > 0:11:15And look, you can see how the toothpaste is squeezed
0:11:15 > 0:11:19through these four holes to make this pretty pattern.
0:11:19 > 0:11:22It's a bit like a star, isn't it?
0:11:22 > 0:11:25It all happens very fast, doesn't it?
0:11:25 > 0:11:29I think this is time for one of my special cameras.
0:11:31 > 0:11:35This camera films things in slow-motion, which means we can see
0:11:35 > 0:11:41things that are really quick, like this machine, slowed right down.
0:11:42 > 0:11:43Are you ready?
0:11:43 > 0:11:44Let's go.
0:11:46 > 0:11:50Watch how our three colours of toothpaste are getting pushed
0:11:50 > 0:11:55into the tubes at the same time, to make perfect stripes.
0:11:55 > 0:11:58Now a stopper is put in the bottom of the tube,
0:11:58 > 0:12:01so the toothpaste doesn't fall out.
0:12:03 > 0:12:06This grabbing arm flips the tubes the right way up,
0:12:06 > 0:12:10and they're ready to go off and be wrapped and packaged.
0:12:10 > 0:12:12The tubes move along here,
0:12:12 > 0:12:16and it looks a bit like a model railway, doesn't it?
0:12:16 > 0:12:19MACHINE CLANKS AND WHIRS
0:12:19 > 0:12:21Can you hear the sound of the machine?
0:12:21 > 0:12:25MACHINE CLANKS AND WHIRS
0:12:25 > 0:12:27It's got quite a good beat.
0:12:29 > 0:12:33Now the tubes of toothpaste go to a robot that wraps
0:12:33 > 0:12:38a label around each one, puts them inside boxes,
0:12:38 > 0:12:41and then they're ready to go to the shops.
0:12:42 > 0:12:48What was your favourite bit about the toothpaste-making factory?
0:12:48 > 0:12:52Do you remember what my favourite kind of toothpaste is?
0:12:52 > 0:12:55That's right, it's stripy.
0:12:55 > 0:12:58Did you hear the sound of the machinery
0:12:58 > 0:13:01as it flipped the toothpaste tubes?
0:13:01 > 0:13:03MACHINE CLANKS AND WHIRS
0:13:06 > 0:13:08It had a really good beat.
0:13:08 > 0:13:09Did you dance too?
0:13:10 > 0:13:15And did you see the way the toothpaste was put inside the tubes?
0:13:15 > 0:13:19That machine was so fast, we had to use my special camera
0:13:19 > 0:13:21to see it in slow motion.
0:13:27 > 0:13:30So, now you know how toothpaste is made
0:13:30 > 0:13:32and how hot water comes out of the taps.
0:13:32 > 0:13:35I think it's time I brushed my teeth and had a bath.
0:13:35 > 0:13:38See you next time.
0:13:40 > 0:13:43# There are lots of things all around us
0:13:43 > 0:13:47# Exciting things that surround us
0:13:47 > 0:13:50- #- But how does it work?- Do you know?
0:13:50 > 0:13:53- #- How is it made?- Do you know?
0:13:53 > 0:13:57- # Do you know?- Let's find out!- #