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 > 0:00:33- # But how does it work? - Do you know?
0:00:33 > 0:00:37- # How is it made? - Do you know?
0:00:37 > 0:00:40- # Do you know? - Let's find out! #
0:00:41 > 0:00:44Hello! I'm Maddie, and today
0:00:44 > 0:00:48I'm tidying my bedroom and having a much-needed sort-out.
0:00:54 > 0:00:56Do you tidy your bedroom?
0:01:00 > 0:01:05It always looks much better after a sort-out, doesn't it?
0:01:05 > 0:01:07Right. Now, let's tackle the wardrobe.
0:01:07 > 0:01:10It's good to sort your clothes out now and then.
0:01:10 > 0:01:14I don't know about you, but I often forget what I've got. Like...
0:01:14 > 0:01:16this hoodie!
0:01:16 > 0:01:19I forgot I had it! And it's one of my favourites.
0:01:19 > 0:01:23I love the colour, and it's really cosy.
0:01:25 > 0:01:27All you have to do is zip it up...
0:01:27 > 0:01:30ZZZZZIP!
0:01:31 > 0:01:33..like that.
0:01:34 > 0:01:38You've probably got some clothes with zips on, too.
0:01:38 > 0:01:40You can get zips on all sorts of things.
0:01:40 > 0:01:41Like your coat,
0:01:41 > 0:01:43or your shoes,
0:01:43 > 0:01:46or even your school bag.
0:01:46 > 0:01:47They're clever, aren't they?
0:01:47 > 0:01:51The way they join two pieces of material together.
0:01:51 > 0:01:55But do you know how a zip works?
0:01:55 > 0:01:56Let's find out.
0:02:02 > 0:02:04ZIP! ZIP! ZIP!
0:02:04 > 0:02:08I love the sound a zip makes when you open and close it.
0:02:08 > 0:02:09Listen carefully.
0:02:09 > 0:02:12ZIP, ZIP-ZIP-ZIP, ZIP-ZIP!
0:02:12 > 0:02:14SHE LAUGHS
0:02:14 > 0:02:17Now, if you look closely at my zip on both sides,
0:02:17 > 0:02:20you can see that all the way from top to bottom
0:02:20 > 0:02:22are these little bumps.
0:02:22 > 0:02:24These bumps are called teeth.
0:02:24 > 0:02:28Now, if I undo my zip, can you see at the bottom, on this side,
0:02:28 > 0:02:31there are two metal bits?
0:02:31 > 0:02:34These are called sliders, and that's because
0:02:34 > 0:02:36they slide up and down.
0:02:36 > 0:02:40And they have a pull-tab on them, so you've got something to hold on to.
0:02:40 > 0:02:43Now, at the bottom on this side of the zip,
0:02:43 > 0:02:47there isn't a slider. There's just this plastic bit.
0:02:47 > 0:02:49It's called the pin.
0:02:49 > 0:02:52To do the zip up, you need to take the pin
0:02:52 > 0:02:54and slide it through the slider
0:02:54 > 0:02:56into this slot.
0:02:56 > 0:02:59When it's securely locked in place,
0:02:59 > 0:03:02you can hold the pull-tab and pull the zip up,
0:03:02 > 0:03:03and I'm in!
0:03:03 > 0:03:07To undo the zip, all you need to do is pull the pull-tab down,
0:03:07 > 0:03:11all the way to the bottom, and it pulls the two sides apart.
0:03:11 > 0:03:14Brilliant! So, that's how you open and close a zip.
0:03:14 > 0:03:19But how does it work? How do the teeth lock together?
0:03:19 > 0:03:22To show you that, we need to look inside a slider.
0:03:24 > 0:03:28Each side of the zip has a row of teeth with gaps in between.
0:03:28 > 0:03:31When the two sides of the zip are lined up,
0:03:31 > 0:03:33the teeth on one side are opposite
0:03:33 > 0:03:35the gaps on the other side.
0:03:35 > 0:03:37To close the zip, the slider is
0:03:37 > 0:03:39pulled down to the bottom,
0:03:39 > 0:03:41and the pin is put inside it.
0:03:41 > 0:03:45Inside the slider, there are two bits, called wedges,
0:03:45 > 0:03:46with grooves in them.
0:03:46 > 0:03:49One wedge is higher than the other.
0:03:49 > 0:03:53The teeth of the zip fit into the grooves of the wedges,
0:03:53 > 0:03:55and when the slider is pulled up,
0:03:55 > 0:03:58it presses one row of teeth on top of the other row of teeth.
0:03:58 > 0:04:01This makes the teeth lock together tightly.
0:04:01 > 0:04:03When the slider is pulled down,
0:04:03 > 0:04:08the teeth are pulled apart from each other, and the zip is opened.
0:04:12 > 0:04:14It's really clever, isn't it?
0:04:14 > 0:04:17Right, this is a special microscope camera.
0:04:17 > 0:04:20It lets us see really small things
0:04:20 > 0:04:24in close detail, like our zip.
0:04:24 > 0:04:28I want to see if we can see those teeth locking together.
0:04:28 > 0:04:31It's going to be a bit fiddly, but let's give it a go.
0:04:31 > 0:04:34SHE GASPS We can see it working!
0:04:35 > 0:04:40You can see the teeth disappearing into the metal slider.
0:04:41 > 0:04:43Shall we try it a bit faster? Ready?
0:04:43 > 0:04:45Downwards, this time.
0:04:45 > 0:04:48Down we go, and now we can see
0:04:48 > 0:04:50the slider is unlocking those
0:04:50 > 0:04:53little teeth and opening the zip!
0:04:55 > 0:04:58I tell you what, let's do the zip back up again,
0:04:58 > 0:05:01and get a close up of the teeth zipped together.
0:05:03 > 0:05:07And actually, when you see them in close up like this,
0:05:07 > 0:05:10they look like bits of jigsaw puzzle, don't they?
0:05:11 > 0:05:15It's amazing how, when you make small things bigger,
0:05:15 > 0:05:17how different they look.
0:05:24 > 0:05:29What did you like most about seeing how a zip works?
0:05:29 > 0:05:32Do you remember the name of the piece you pull up to close
0:05:32 > 0:05:35the two sides of the zip together?
0:05:35 > 0:05:39That's right - it's called the slider.
0:05:39 > 0:05:41Did you hear the sound the zip made
0:05:41 > 0:05:44when I opened and closed it really fast?
0:05:44 > 0:05:47ZIP! ZIP-ZIP-ZIP! ZIP-ZIP!
0:05:47 > 0:05:48SHE LAUGHS
0:05:48 > 0:05:50And did you see how the teeth of the zip
0:05:50 > 0:05:53were pressed together by the slider?
0:06:01 > 0:06:05So, the next time you use a zip, you'll know just how it works,
0:06:05 > 0:06:09with all those little teeth locking together inside the slider.
0:06:09 > 0:06:11I really do love this hoodie,
0:06:11 > 0:06:14especially because of the picture on the back.
0:06:16 > 0:06:18Fun, isn't it?
0:06:18 > 0:06:21Do you have any clothes with a picture on?
0:06:21 > 0:06:22Maybe it's a tractor,
0:06:22 > 0:06:25your favourite animal, or a fairy?
0:06:25 > 0:06:30But do you know how a picture like this gets onto your clothes?
0:06:30 > 0:06:32Do you know how it's made?
0:06:32 > 0:06:34Let's find out.
0:06:44 > 0:06:46This is a workshop,
0:06:46 > 0:06:49and the team here do something called screen printing.
0:06:49 > 0:06:52Screen printing is the type of printing used
0:06:52 > 0:06:55to put pictures on clothes for us to wear.
0:06:55 > 0:06:59Let's see how a screen-printed T-shirt is made.
0:06:59 > 0:07:01The first thing we need to do is choose
0:07:01 > 0:07:04the picture we want to put on our T-shirt.
0:07:08 > 0:07:10How about a dinosaur?
0:07:10 > 0:07:12I love dinosaurs.
0:07:12 > 0:07:15I think a dinosaur would be great on a T-shirt.
0:07:17 > 0:07:21This is George, and he's going to print out the outline of
0:07:21 > 0:07:24our dinosaur picture in black ink, onto this clear film.
0:07:24 > 0:07:28It's a bit like printing something from your computer at home.
0:07:29 > 0:07:33Look - our dinosaur has been printed in black ink.
0:07:33 > 0:07:37But how does our brilliant dinosaur get onto a T-shirt?
0:07:37 > 0:07:42For the next step, we need one of these - it's called a screen.
0:07:42 > 0:07:46Can you see there are lots of tiny holes all over the screen?
0:07:46 > 0:07:50This material is called mesh, and those tiny holes let the ink
0:07:50 > 0:07:54for our picture pass through the screen and go onto our T-shirt.
0:07:54 > 0:07:58But at the moment there are holes all over the screen,
0:07:58 > 0:08:00so if we tried to put ink on our T-shirt,
0:08:00 > 0:08:03we'd just get one big square.
0:08:04 > 0:08:07To print our dinosaur onto a T-shirt,
0:08:07 > 0:08:09we need to make a dinosaur-shaped
0:08:09 > 0:08:12stencil on the screen.
0:08:12 > 0:08:15Stencilling is when you paint through the holes of a shape
0:08:15 > 0:08:17onto something beneath.
0:08:17 > 0:08:21Have you used a stencil before? Maybe at school, nursery,
0:08:21 > 0:08:22or at home?
0:08:25 > 0:08:27To make the stencil,
0:08:27 > 0:08:29Barry puts a layer of special paint
0:08:29 > 0:08:33called emulsion all over the screen.
0:08:33 > 0:08:38This emulsion blocks all of the tiny holes in the mesh.
0:08:42 > 0:08:45Can you see that the holes are blocked,
0:08:45 > 0:08:47so you can't see through any more?
0:08:47 > 0:08:49And no ink would be able to get through.
0:08:49 > 0:08:53Next, we need to make the shape of the dinosaur on the emulsion.
0:08:55 > 0:08:58To do that, the dinosaur image is put onto
0:08:58 > 0:09:01a very special machine with a bright light.
0:09:01 > 0:09:04Then, the screen goes on top.
0:09:04 > 0:09:08The light will make the emulsion go hard everywhere
0:09:08 > 0:09:11except the lines of our dinosaur.
0:09:18 > 0:09:20It only takes a few seconds to work,
0:09:20 > 0:09:23but you can't see anything yet
0:09:23 > 0:09:26because the screen needs to be washed first.
0:09:36 > 0:09:40The emulsion that wasn't hardened by the light stayed soft,
0:09:40 > 0:09:44which meant it could be washed away by the pressure washer.
0:09:44 > 0:09:46Let's take a look and see what happened.
0:09:46 > 0:09:51Oh, look! So, all of that washing has revealed the dinosaur stencil!
0:09:53 > 0:09:57To see where the emulsion has been hardened by the bright light,
0:09:57 > 0:10:00and has blocked off all those tiny holes in the mesh,
0:10:00 > 0:10:03I'm going to use my special camera.
0:10:03 > 0:10:05This is a microscope.
0:10:05 > 0:10:08It helps us to see very small things in detail.
0:10:08 > 0:10:10So, let's put the microscope
0:10:10 > 0:10:12on the blue bits of the screen.
0:10:12 > 0:10:15This is where the emulsion has blocked up the holes.
0:10:15 > 0:10:18And, if you see, you can't see through it, can you?
0:10:18 > 0:10:21All you can see is blue.
0:10:21 > 0:10:24But, if I move it over to the dinosaur's eye,
0:10:24 > 0:10:27where the emulsion was washed away - look.
0:10:27 > 0:10:31You can now see those tiny holes in the mesh,
0:10:31 > 0:10:35so when we put ink on the screen, the ink will go through the holes,
0:10:35 > 0:10:37but won't be able to go through the blue bits.
0:10:37 > 0:10:40And this is how we have made a stencil.
0:10:42 > 0:10:47Our screen with the dinosaur stencil has been placed in this machine.
0:10:47 > 0:10:51It's called a carousel, because it goes round and round.
0:10:51 > 0:10:54But now it's time for the really fun bit.
0:10:55 > 0:10:59Barry now puts the coloured ink in our stencilled frame.
0:10:59 > 0:11:02Can you see what colour it is?
0:11:02 > 0:11:04It's green!
0:11:14 > 0:11:16Now the T-shirt is in place,
0:11:16 > 0:11:19Barry is going to use one of these.
0:11:19 > 0:11:22This tool is called a squeegee. It's a great word, isn't it?
0:11:22 > 0:11:26He squeezes the ink from the bottom of the screen
0:11:26 > 0:11:30all the way to the top, and this pushes the green ink through
0:11:30 > 0:11:33all those little holes in our dinosaur stencil.
0:11:33 > 0:11:35SQUEAK!
0:11:35 > 0:11:37It's a really good sound, isn't it?
0:11:37 > 0:11:39What do you think will happen
0:11:39 > 0:11:42when he lifts the screen back up again?
0:11:44 > 0:11:47A dinosaur T-shirt! That's amazing!
0:11:49 > 0:11:53The great thing about it is you can use the screen again and again
0:11:53 > 0:11:55to make more T-shirts!
0:11:57 > 0:12:01Our T-shirt looks great, but it's not quite ready for me to wear yet.
0:12:01 > 0:12:04The ink is still wet.
0:12:04 > 0:12:07So, what do you think happens next?
0:12:07 > 0:12:10Our T-shirt goes into a special drying machine until the ink
0:12:10 > 0:12:12is set and dry.
0:12:12 > 0:12:14This is called curing.
0:12:14 > 0:12:18Once the T-shirt has been cured, the pattern won't rub off,
0:12:18 > 0:12:21and it won't wash off in the washing machine either.
0:12:21 > 0:12:25So, there's only one thing left to do - try it on.
0:12:25 > 0:12:30What did you like most about seeing our dinosaur being screen printed?
0:12:31 > 0:12:35Do you remember the name of the material the ink goes through,
0:12:35 > 0:12:37with lots of little holes in it?
0:12:37 > 0:12:40That's right - it's called mesh.
0:12:40 > 0:12:43Did you hear the sound the squeegee made as Barry
0:12:43 > 0:12:46pulled it from the top to the bottom of the screen?
0:12:46 > 0:12:48SQUEAK!
0:12:52 > 0:12:57And did you see how the stencil looked on my special camera?
0:12:57 > 0:13:01You could see all the little holes which the ink went through.
0:13:05 > 0:13:09Ta-da! My brand-new dinosaur T-shirt. What do you think?
0:13:09 > 0:13:12So, now you know how pictures get put on T-shirts,
0:13:12 > 0:13:15and you know how zips work.
0:13:15 > 0:13:18So, you can tell your friends and family how the little teeth
0:13:18 > 0:13:20pull together inside the slider.
0:13:20 > 0:13:25Right, it's time for me to go home, so I'll see you next time.
0:13:27 > 0:13:30# There are lots of things All around us
0:13:30 > 0:13:34# Exciting things That surround us
0:13:34 > 0:13:37- # But how does it work? - Do you know?
0:13:37 > 0:13:41- # How is it made? - Do you know?
0:13:41 > 0:13:44- # Do you know? - Let's find out! #