Zips and Screen Printing Do You Know?

# There are lots of things All around us

# Exciting things That surround us

-# But how does it work?

-Do you know?

-# How is it made?

-Do you know?

# Things that go up Things that go down

# Things that go pop! Things that go round

# With special cameras To show you inside

# It's going to be A big surprise

-# But how does it work?

-Do you know?

-# How is it made?

-Do you know?

-# Do you know?

-Let's find out! #

Hello! I'm Maddie, and today

I'm tidying my bedroom and having a much-needed sort-out.

Do you tidy your bedroom?

It always looks much better after a sort-out, doesn't it?

Right. Now, let's tackle the wardrobe.

It's good to sort your clothes out now and then.

I don't know about you, but I often forget what I've got. Like...

this hoodie!

I forgot I had it! And it's one of my favourites.

I love the colour, and it's really cosy.

All you have to do is zip it up...

ZZZZZIP!

..like that.

You've probably got some clothes with zips on, too.

You can get zips on all sorts of things.

Like your coat,

or your shoes,

or even your school bag.

They're clever, aren't they?

The way they join two pieces of material together.

But do you know how a zip works?

Let's find out.

ZIP! ZIP! ZIP!

I love the sound a zip makes when you open and close it.

Listen carefully.

ZIP, ZIP-ZIP-ZIP, ZIP-ZIP!

SHE LAUGHS

Now, if you look closely at my zip on both sides,

you can see that all the way from top to bottom

are these little bumps.

These bumps are called teeth.

Now, if I undo my zip, can you see at the bottom, on this side,

there are two metal bits?

These are called sliders, and that's because

they slide up and down.

And they have a pull-tab on them, so you've got something to hold on to.

Now, at the bottom on this side of the zip,

there isn't a slider. There's just this plastic bit.

It's called the pin.

To do the zip up, you need to take the pin

and slide it through the slider

into this slot.

When it's securely locked in place,

you can hold the pull-tab and pull the zip up,

and I'm in!

To undo the zip, all you need to do is pull the pull-tab down,

all the way to the bottom, and it pulls the two sides apart.

Brilliant! So, that's how you open and close a zip.

But how does it work? How do the teeth lock together?

To show you that, we need to look inside a slider.

Each side of the zip has a row of teeth with gaps in between.

When the two sides of the zip are lined up,

the teeth on one side are opposite

the gaps on the other side.

To close the zip, the slider is

pulled down to the bottom,

and the pin is put inside it.

Inside the slider, there are two bits, called wedges,

with grooves in them.

One wedge is higher than the other.

The teeth of the zip fit into the grooves of the wedges,

and when the slider is pulled up,

it presses one row of teeth on top of the other row of teeth.

This makes the teeth lock together tightly.

When the slider is pulled down,

the teeth are pulled apart from each other, and the zip is opened.

It's really clever, isn't it?

Right, this is a special microscope camera.

It lets us see really small things

in close detail, like our zip.

I want to see if we can see those teeth locking together.

It's going to be a bit fiddly, but let's give it a go.

SHE GASPS We can see it working!

You can see the teeth disappearing into the metal slider.

Shall we try it a bit faster? Ready?

Downwards, this time.

Down we go, and now we can see

the slider is unlocking those

little teeth and opening the zip!

I tell you what, let's do the zip back up again,

and get a close up of the teeth zipped together.

And actually, when you see them in close up like this,

they look like bits of jigsaw puzzle, don't they?

It's amazing how, when you make small things bigger,

how different they look.

What did you like most about seeing how a zip works?

Do you remember the name of the piece you pull up to close

the two sides of the zip together?

That's right - it's called the slider.

Did you hear the sound the zip made

when I opened and closed it really fast?

ZIP! ZIP-ZIP-ZIP! ZIP-ZIP!

SHE LAUGHS

And did you see how the teeth of the zip

were pressed together by the slider?

So, the next time you use a zip, you'll know just how it works,

with all those little teeth locking together inside the slider.

I really do love this hoodie,

especially because of the picture on the back.

Fun, isn't it?

Do you have any clothes with a picture on?

Maybe it's a tractor,

your favourite animal, or a fairy?

But do you know how a picture like this gets onto your clothes?

Do you know how it's made?

Let's find out.

This is a workshop,

and the team here do something called screen printing.

Screen printing is the type of printing used

to put pictures on clothes for us to wear.

Let's see how a screen-printed T-shirt is made.

The first thing we need to do is choose

the picture we want to put on our T-shirt.

How about a dinosaur?

I love dinosaurs.

I think a dinosaur would be great on a T-shirt.

This is George, and he's going to print out the outline of

our dinosaur picture in black ink, onto this clear film.

It's a bit like printing something from your computer at home.

Look - our dinosaur has been printed in black ink.

But how does our brilliant dinosaur get onto a T-shirt?

For the next step, we need one of these - it's called a screen.

Can you see there are lots of tiny holes all over the screen?

This material is called mesh, and those tiny holes let the ink

for our picture pass through the screen and go onto our T-shirt.

But at the moment there are holes all over the screen,

so if we tried to put ink on our T-shirt,

we'd just get one big square.

To print our dinosaur onto a T-shirt,

we need to make a dinosaur-shaped

stencil on the screen.

Stencilling is when you paint through the holes of a shape

onto something beneath.

Have you used a stencil before? Maybe at school, nursery,

or at home?

To make the stencil,

Barry puts a layer of special paint

called emulsion all over the screen.

This emulsion blocks all of the tiny holes in the mesh.

Can you see that the holes are blocked,

so you can't see through any more?

And no ink would be able to get through.

Next, we need to make the shape of the dinosaur on the emulsion.

To do that, the dinosaur image is put onto

a very special machine with a bright light.

Then, the screen goes on top.

The light will make the emulsion go hard everywhere

except the lines of our dinosaur.

It only takes a few seconds to work,

but you can't see anything yet

because the screen needs to be washed first.

The emulsion that wasn't hardened by the light stayed soft,

which meant it could be washed away by the pressure washer.

Let's take a look and see what happened.

Oh, look! So, all of that washing has revealed the dinosaur stencil!

To see where the emulsion has been hardened by the bright light,

and has blocked off all those tiny holes in the mesh,

I'm going to use my special camera.

This is a microscope.

It helps us to see very small things in detail.

So, let's put the microscope

on the blue bits of the screen.

This is where the emulsion has blocked up the holes.

And, if you see, you can't see through it, can you?

All you can see is blue.

But, if I move it over to the dinosaur's eye,

where the emulsion was washed away - look.

You can now see those tiny holes in the mesh,

so when we put ink on the screen, the ink will go through the holes,

but won't be able to go through the blue bits.

And this is how we have made a stencil.

Our screen with the dinosaur stencil has been placed in this machine.

It's called a carousel, because it goes round and round.

But now it's time for the really fun bit.

Barry now puts the coloured ink in our stencilled frame.

Can you see what colour it is?

It's green!

Now the T-shirt is in place,

Barry is going to use one of these.

This tool is called a squeegee. It's a great word, isn't it?

He squeezes the ink from the bottom of the screen

all the way to the top, and this pushes the green ink through

all those little holes in our dinosaur stencil.

SQUEAK!

It's a really good sound, isn't it?

What do you think will happen

when he lifts the screen back up again?

A dinosaur T-shirt! That's amazing!

The great thing about it is you can use the screen again and again

to make more T-shirts!

Our T-shirt looks great, but it's not quite ready for me to wear yet.

The ink is still wet.

So, what do you think happens next?

Our T-shirt goes into a special drying machine until the ink

is set and dry.

This is called curing.

Once the T-shirt has been cured, the pattern won't rub off,

and it won't wash off in the washing machine either.

So, there's only one thing left to do - try it on.

What did you like most about seeing our dinosaur being screen printed?

Do you remember the name of the material the ink goes through,

with lots of little holes in it?

That's right - it's called mesh.

Did you hear the sound the squeegee made as Barry

pulled it from the top to the bottom of the screen?

SQUEAK!

And did you see how the stencil looked on my special camera?

You could see all the little holes which the ink went through.

Ta-da! My brand-new dinosaur T-shirt. What do you think?

So, now you know how pictures get put on T-shirts,

and you know how zips work.

So, you can tell your friends and family how the little teeth

pull together inside the slider.

Right, it's time for me to go home, so I'll see you next time.

# There are lots of things All around us

# Exciting things That surround us

-# But how does it work?

-Do you know?

-# How is it made?

-Do you know?

-# Do you know?

-Let's find out! #