Bridges Nina and the Neurons

# If you've got a question and you don't know where to go

# Ask Nina for some help Cos she's got a science show

# She makes sense of her senses While helping all her fans

# By doing her experiments with potions and with bangs

# Touch your tongue Tongue

# Fingers Fingers

# Eyes Eyes Ears Ears

# Nose Nose

# Nina and the Neurons find out what you need to know

# Nina and the Neurons find out what you need to know

# Luke, he helps us with our eyes and Felix with our touch

# Ollie sniffs out smells and scents and Belle she hears so much

# Bud is Ollie's brother, he helps us with our taste

# They're Nina's little Neurons and they're coming to your place

# Touch your tongue Tongue

# Fingers Fingers

# Eyes Eyes Ears Ears

# Nose Nose

# Nina and the Neurons find out what you need to know, yeah!

# Nina and the Neurons find out what you need to know

# Oh, yeah! #

Oh, come on, Nina, here we go.

Oh, hello there.

I'm just about to do a very cool experiment.

Here we go.

Oop.

Ah!

It's all staying up because it's perfectly balanced.

ALARM BEEPS

I hear a beep. I see a flash. I wonder what they are going to ask?

-ALL: Hi, Nina.

-Hi.

We've got a question for you.

How does a bridge work?

Oh, that's a great question.

How does a bridge work?

Now, a bridge is a big structure.

It's built over rivers so that things get across it.

Why don't you come down to my workshop and we'll investigate?

ALL: See you soon, Nina. Bye.

Bye.

Well, I'm going to need some help to answer this one

and I know just who to ask.

OK, Neurons, time to get to work.

ALL: Neurons at the ready, Nina.

OK. Today's question is, "How does a bridge work?"

Which Neuron do you think will be most useful in helping us

find the answer?

It's Felix!

Go, Felix. Go, Felix. Go, Felix. Go, Felix. Go, Felix.

Marvellous. A little touch can mean so much, Nina.

Today's question is, "How does a bridge work?"

and because bridges help hold things up,

Felix our touch Neuron will be helping us today

but stand by, Neurons,

I've a feeling I mean need help from all of you.

I need to get the workshop ready before the experimenters arrive.

Billie loves sandwiches.

Alexander likes making up his own stories.

Marianna loves dancing.

But they all want to know, how does a bridge work?

So today, for one day only,

Billie, Alexander and Marianna become the experimenters.

-Hi, guys.

-ALL: Hi, Nina.

Welcome to my workshop and thank you for your great question,

how does a bridge work?

There are lots of different types of bridges.

Some are straight, some are arches

and some bridges have strong cables.

Have a look at this one.

This is the Forth Bridge and it is a special type.

It's called a cantilever bridge.

-Canti... what?

-A cantilever, Bud.

It is a tricky word.

Cantilevers are only held up at one end.

The other end has to stay up by itself.

How does it work, Nina?

Oh, let's try an experiment with our very own cantilevers to find out.

ALL: Woo-woo! An experiment. We're ready, Nina.

So, here we have some cantilevers

and, as you can see, they're only held up at one end.

These have been specially made

so you should never try something like this yourself.

These cantilevers are all the same thickness

but they are all different lengths.

And I would like you guys to try standing on them

to see if they'll hold your weight. OK.

So, Billie, I'd like you to stand on the shortest one. Up you go.

Good lass. Stand right at the end.

OK, Marianna, a big step up. Good girl.

Excellent. Now carefully walk to the end.

So what happened? Are your cantilevers holding you up?

My one's bending.

Oh, yes. The longest cantilever is feeling a bit bendy.

You're right. Your long cantilever is bending.

So shorter cantilevers can hold up weight more easily.

But if a cantilever is longer, it's more difficult

for it to hold up weight.

Well done, experimenters. Let me get you down.

So the Forth Bridge is a cantilever bridge.

And cantilevers are only held up at one end.

But the longer the cantilever gets,

the more difficult it is for it to hold something up.

Exactly, Neurons.

But cantilever bridges need to be really long

to get across big rivers.

I wonder if there is a way that we can help long cantilevers

to stay up?

I think we need to go on a trip to a really big river to find out more.

Oh, goody. I love this bit.

I wonder where Nina is taking us.

Nina said we were going to a big river.

Oh, oh, maybe we are going on a boat.

Or in for a swim.

Look, everyone. We're here.

So I've brought you to this big river to see a very special bridge.

Do you recognise it?

-It's the Forth Bridge.

-It is the Forth Bridge, near Edinburgh,

and it was built a long time ago.

ALL: Ooh! It's really long.

Even though this bridge has long cantilevers

it can still hold up heavy trains without bending.

I think we need to do an experiment to find out how it works.

We've got three cantilevers here

and they're all the same length.

Marianna, your one has no extra beams.

Billie, your one has a beam underneath

and Alexander, you have a long cantilever

with a beam underneath and on top.

And we also have some lovely heavy weights there.

So let's see if the beams help the long cantilever

to hold up more weight.

We're going to add the weights at the same time, so are you ready?

-ALL: Yeah.

-OK, here we go.

Pick up your first weight

and pop it on to the end of your long cantilever.

Oh, dear.

That long cantilever looks bent already.

Oh, no. What happened?

Mine's bent.

Yes, your long cantilever without the beams

is already starting to bend.

So it could only hold up one weight.

OK, so let's see if we can add some more weight to the other two here.

So pick up another weight for me.

That's it. And pop it right at the end.

OK.

They are looking pretty good.

Let's add another weight.

Very good.

OK. Pick up another weight for me. Pop it on.

Oh, look, Billie.

Your cantilever with the beams underneath

is starting to bend now and that's got one, two, three,

four weights on it.

OK, well, Alexander, I think we could keep trying to put

weights on your cantilever, so do you want to keep going?

Wow. It's holding lots of weights.

Look at that.

There are no more weights to put on.

You've put all six on

and it's still not bending.

That's fantastic.

When a weight is added

the cantilever is pushed down

and the beam and underneath pushes up, which stops it from bending.

And if there is a beam on top as well, that's even better.

So as well as the beam underneath pushing up,

there's a beam on top pulling up at the same time.

And this is how a really long cantilever can hold up

a lot of heavy weights.

And the Forth Bridge is made like this, too.

So the long cantilevers are joined by the towers at the end

and there's a beam on top of the long cantilever

that helps to pull it up

and there's a beam underneath the cantilever

that helps to push it up, too,

which means that it can hold up all the heavy trains that go over it.

So that's how they stop the long cantilever from bending?

There's a beam on top and underneath.

Which means it can hold up really heavy things like trains.

Choo-choo!

Well remembered, Neurons.

-The bridge is really strong, Nina.

-It is.

And, actually, that reminds me of a really fun experiment

and I'll be needing some strong helpers.

So your question was, "How does a bridge work?"

And so far we've discovered that adding a beam on top

and underneath a long cantilever bridge stops it from bending.

And that means it can hold up heavy things like trains.

And I think we need to do one final experiment.

Do you think we could build a human cantilever bridge using our bodies?

-ALL: Yes.

-Well, let's do it.

Into your seats, guys. That's it, round you go.

Now lift up those poles.

A human cantilever bridge.

Nina thinks of the most unusual experiments.

But they're the most fun.

Oh, wow.

You've built a great bridge and it looks just like the Forth Bridge.

So you guys are the towers' experimenters

and you're holding up the middle sections of the bridge.

Your arms are the top beams

and the poles are the beams underneath

and there's also some heavy weights at the sides

just helping you balance.

I think we need to put this bridge to the test.

Do you think your lovely bridge could hold up

these heavy trains?

-Yes.

-Well, I think we need to try.

Here we go. Choo-choo.

OK.

Whoa! It's holding them up.

It's like magic.

It seems like magic, Bud, but it isn't.

It's clever building.

So what do you feel in your arms?

They're being pulled.

Just like the beams on top of the bridge.

And what does it feel like the poles underneath are doing?

-Pushing my arms up.

-Exactly.

So your arms on top are pulling and the poles underneath are pushing.

And that's what's holding up the middle sections of the bridge.

Well done, experimenters.

So, your question was, "How does a bridge work?"

and I think we've answered it.

We found out that the Forth Bridge is a cantilever bridge.

Cantilevers are only held up at one end.

The longer the cantilever gets,

the more difficult it is for it to hold something up.

When there's weight on it, the beams on top pull and the beams

underneath push so the bridge can hold up heavy things like trains.

So, I hope that's answered your question.

ALL: Thanks, Nina. Bye.

You're welcome. Bye.

If you want to know more about the science that's all around us,

go to the Nina section on the CBeebies website. Have fun.

# Superstructures, superstructures Superstructures, superstructures

# Some of them are tall

# Some of them are wide

-# They're bumpy, lumpy, wiggly too

-Wiggly too

# Some of them are strong

-# Some of them are small

-Like me

# They're windy, whirly, whooshy too

# All around

# Look over here

# Build it, stack it, pile it up

# Come on, let's get building

# Race it, hold it, make it stick

# Come on, let's get building

# Come on, let's get building

# Some of them are cosy warm

# Some of them are chilly

# Keep us safe and hide us too

# Some of them are just for fun or help us to stay dry

# They're underground and high up too

# Look around

# Over here

# Build it, stack it, pile it up

# Come on, let's get building

# Race it, hold it, make it stick

# Come on, let's get building

# Come on, let's get building! #

And remember there are superstructures everywhere,

whether they're big or small, wide or tall,

we can all get building.

See again soon. Bye.

Bye. Get building!