Episode 6 The Secrets of Everything

'Humans are an incredible species.'

We've found ways to talk to each other on opposite sides of the world.

We've discovered cures for terrible diseases.

And some of us have even left this planet to explore space.

But there's still so much left to find out.

I'm Greg Foot. Ever since I was a kid, I've been into science.

I've always been asking questions, and taking things apart to understand how they work.

I was the kid trawling through the rock pools

and the one that tried to turn his bike into an aeroplane.

I even went on to do a science degree.

'And I'm still asking questions.'

-This is gonna hurt, right?

-Yeah.

'And I reckon a lot of you are, too.'

And that's what this series is all about.

Getting to the bottom of all those questions that never get properly answered,

to reveal the Secrets of Everything.

'On this, the final episode of The Secrets of Everything,

'it's a battle for survival.

'I lose my mind trying to dig to Australia.'

-HE LAUGHS

-My brain doesn't work!

'I take a dip in deadly quicksand.'

OK, that's not going to work.

'And stuff myself with artery-clogging fast food.'

-HE SIGHS

-OK, that was over 1,000 calories, just for breakfast.

'But first, the secrets of life and death.'

So, I know that my heart is just flesh and blood like the rest of me.

But I still attach emotions to it.

I definitely say that I've been heartbroken before.

But what I want to know is, if a girl was to hurt me badly enough,

could I die of a broken heart?

# You, and your heart

# Should they feel so far apart? #

'To see if this is possible, I first need to find myself a heart.'

'To help me is Home Office pathologist Dr Stewart Hamilton.'

-Hi, Stewart.

-Hi.

'And a recently deceased pig.'

'It was destined for the butcher's but, like scientists have done for centuries before us,

'we're going to use it for research purposes.'

So, a pig is a good match for a human, right?

Yeah, physically very similar, physiologically very similar.

And the heart, to all intents and purposes, nearly identical to a human one.

Brilliant. Well, first things first, we need to expose it.

So, right bang in the middle of the chest, there is the heart.

-Ooh, it's heavy.

-It is.

-It's a lot heavier than I thought.

-So, although this is a pig's heart, this is the closest we can get to a human heart?

-Yeah.

I take it you've seen a few human hearts in your time?

Erm, probably only about 2,500!

Ha! So yeah, quite a few.

I'm not sure if someone gave it to me I'd be able to tell the difference.

-Really? They're that similar?

-That similar.

-Oh, right!

That does not look anything like you get on a Valentine's Day card.

No, there's nothing terribly emotional about it.

'Your heart isn't there to win a beauty contest. It's a muscle with a job to do.

Blood packed with oxygen from the lungs is delivered to your heart

through the pulmonary vein

before being fired out to the body through the aorta.

Round and round, all day and all night, driven by about 2.5 billion heartbeats in an average lifetime.

The heart, in reality, is simply a pump.

It's there to pump blood round your body, and keep you working.

No different to the pump on your central heating system.

And, just like a water pump, it can go wrong.

Put yourself on a diet of lard and fags, if you want to experience it for yourself.

But there is a kind of heart problem you can't do anything about.

If my girlfriend was to dump me tomorrow,

I'd obviously be really upset.

But could that break my heart in the same way?

-Well, actually, yes, it could.

-Really?

There are two possibilities. One is that, in somebody who already has a degree of heart disease,

that stress can tip the heart over the edge.

But even somebody with a healthy heart,

when you get stressed, you release a load of adrenaline into your body.

Your heart rate goes up, your blood pressure goes up.

And there is actually a condition, which is known as takotsubo cardiomyopathy,

which is not easy to say twice!

But most people would call it "broken heart syndrome"

where that adrenaline actually stuns the muscle fibres in the heart

and stops them working.

WOMAN SCREAMS

It's more common in older ladies, but it can happen to anyone.

And, in the most extreme cases, it can kill you.

-HE SIGHS

-That's amazing. That's amazing.

So, if you don't want to die of a broken heart,

a little light exercise and the occasional bunch of flowers could go a long, long, long way.

# Come back and mend my broken heart... #

When I was a kid, I knew quicksand was fatal.

I knew it was a killer because I'd seen it suck people to their deaths in films.

But if you found yourself in quicksand, would it really be the end?

Depends how quick the quicksand is.

I'm sure you're supposed to stand still, because struggling makes it worse.

Try and keep moving. Stand still, get your phone out,

call your mum or 999, and then that's it.

# I'm in the quicksand!

# I'm in the quicksand! #

'Before I get sucked into this one,

'I want to find out just how quicksand works.

'To do that, I'm going to need a trough full of custard powder. Obviously!

'Most liquids, as we all know, tend to be runny

'and they normally stay that way unless the temperature changes.'

But other liquids, like quicksand or bizarrely custard, corn flour, behave in a much weirder way.

When I dip my toe in, it completely vanishes, it behaves like a liquid.

But when I kick it, it behaves like a solid.

So I'm going to try to walk on water. Well, custard.

Yes!

'Although it might look like a miracle,

'I'm able to walk on the custard

'because it belongs to a weird bunch of liquids called non-Newtonian fluids.'

'Unlike normal liquids,

they get thicker or thinner under pressure.

'Quicksand is another one of these bizarre fluids.

'It's just a mixture of sand, water and clay

'and it looks quite solid on the surface.

'But, step on to it, and you're in trouble.'

The first thing that happens...

-HE LAUGHS

-..is it turns really liquidy.

And I sink in. And then, straight after, the quicksand separates into two layers.

At the top, it's more watery.

But below that, down where my foot is, it's a lot more sandy.

'The quicksand has behaved just as weirdly as the custard, but in the opposite way.

'Under the pressure of my foot, it gets runnier.

'And then, as I sink down, it feels like it's grabbing my leg like a vice.'

And it's that that is stopping me pulling it out.

'So if I was fully submerged in its grip, would anyone be strong enough to pull me out?'

This one requires my stunt double!

# I love ya, you dummy! #

Ugh.

-Right, I think we're going to need muscle for this. Right, are you ready?

-OK.

One, two, three. Argh!

Ugh. No, no. I don't think we can do that.

I think we need reinforcements.

'This lorry has some serious power.

'It's normally used for lifting 10-ton skips,

'so hopefully it's got enough oomph to get our dummy unstuck.'

Ooh! Head's off! Argh!

I think we're free. Come on, last bit. Yes.

That took a skip lorry to pull him out.

Scientists have actually calculated it can take the same force you need to lift a small car.

'Seeing as the chances of having a skip lorry to hand if you're stuck in quicksand are quite low,

'I'm now going to see whether there's any technique I can use

'to wrestle myself free from its clutches.'

Whoa! OK. This is kind of scary.

You feel like it's sucking you in.

There's just nothing underneath my feet, there's no firm platform.

Argh!

I've gotta find a way to get out.

'In fact, because of the strange behaviour of quicksand under pressure,

'flailing around is not a good idea.

'You'll waste precious energy, and it makes it more runny.'

OK, that's not going to work.

'But even though it looks like I'm in real trouble,

'there's no way I'm ever going to sink further than my waist.'

HE LAUGHS

'And that's because my body is less dense than quicksand, so I'm actually floating in it.

'Quicksand's reputation as a killer isn't because you drown in it,

'it's because, if you're stuck in it and the tide comes in, you're a goner.'

'But there is a way to get out,

'and that's by spreading your weight and making very small movements upwards.'

Yeah! Come on, that's it, last bit.

'I still need a bit of help, though.'

-Oh my!

-You all right?

-Oh! Oh!

Right, who's next?

-No?

-Not today!

Right, check this out. It's a beautiful demonstration

of one of the simplest ideas in science, that hot air rises.

That flame's heating up all the air inside.

It's less dense than the cold air around it.

Up it goes.

So why then are mountains, the highest places on the Earth, freezing cold?

# Ain't no mountain high enough

# Nothing can keep me, Keep me from you. #

If there's anybody who can help me get to the bottom of this one,

it's a man who's a chemist,

practical engineer, meteorologist and...

..Polish musician?

He is Dr Zbigniew Szydlo. I just call him Doc.

All right, Doc?

Great to see you! Fridge sorted. See you in a few minutes then, OK?

OK, so I'm down here, literally a couple of metres above sea level.

Doc is up at the top of the hill.

It's 17C down here.

I'm going to bike up to meet him and see what happens to the temperature.

# So we go out to the hill We lie down. #

'You'd think that the higher you get, the warmer it should become,

what with all that warm air floating upwards.'

Right, I'm now at 130 metres above sea level.

The weather hasn't really changed, but the temperature is now creeping down.

We've just touched 16 degrees.

OK. Onwards to the top.

'But surely, if you climb up a mountain, you're getting nearer to the sun?'

'The problem is, temperatures actually drop by about one degree every 100 metres you climb.'

It just doesn't seem to make sense, but it's true.

And, to find out why it happens, I need to investigate a fundamental force of nature.

Talking of which, there's Doc.

-Hi, Doc.

-Oh, you're here, brilliant!

-Hello, matey.

-Can you give us a hand with this then?

OK, let's go then. Are you all ready? No, grab with the other side.

Up from underneath. One, two, three, lift. Brilliant!

-Where we going?

-We're going in here.

Right, drop this down here.

Right, Doc. Your challenge is to make a mountain out of a fridge.

-Brilliant.

-Doc.

-Yeah?

-Keep cool!

'Doc's an expert at dismantling things.

'But if you're not, it's obviously not a good idea to try this at home.

'While he's doing that,

'I'm going to use this tyre to investigate how pressure can effect temperature.'

Hopefully, when I fill this full of air, let's see what happens.

'The green and yellow bits show where it's warmer.

'As more and more air molecules are pumped in,

'the energy increases, and that raises the temperature.'

And the reverse is also true.

If you open the valve, all that air comes flying out.

It expands. You're losing all those energetic air molecules,

and the temperature goes down.

It's one of the fundamental laws of nature,

Compress a gas and it heats up.

Let it expand, and it cools down.

OK? Yep.

'And this is exactly what's happening in Doc's fridge.'

-Right. So we're plugging her in, and see what happens?

-Yeah.

'The fridge works because the gas here in the bottom is compressed, so it's warm.

'But, as it's allowed to expand rapidly around the ice box,

'it cools right down to below zero,

'cold enough to make ice.'

'And, bizarrely, Doc's fridge works a bit like planet Earth.

The air at the bottom of the fridge is a bit like the air at sea level.

It's relatively warm because it's being compressed,

this time by miles of atmosphere above it.

Further up, there's less atmosphere,

fewer air molecules bashing about,

less energy and, just like Doc's ice box, it's colder.

And that's why the top of mountains...

..are freezing.

-Time for an ice cream.

-Yeah. Let's go to the beach. It's warmer down there.

-Absolutely.

-NARRATOR:

-Here's Professor Logic. How do you do, Professor?

Professor Logic is a busy man.

So much to see, so much to learn, so much to measure.

Today, Professor Logic is observing space.

And he's rather excited because he's discovered something new.

Ah ha!

Er, what is it?

I'm afraid you're going to have to help me here, Professor.

I see. You've discovered a black hole.

Well, that is exciting.

Why is it called a black hole, Professor?

Because you can't see it.

And how do you know if you've discovered it in the first place?

A black hole forms when a large star burns out and implodes.

All its matter collapses into a dense point that you can't see.

How very inconvenient, Professor.

But, you know, it's there because its gravitational field is so strong

that it sucks up everything around it, even light.

Well, don't get too close, you might get sucked up yourself.

You want to get sucked up?

But, once you're in, doesn't something called spaghettification

stretch you out into an enormous string of atoms,

before crushing you into a soup of collapsed subatomic particles?

Doesn't sound much like fun to me.

You don't care?

You've heard that black holes might be gateways to other universes?

And you want to meet the inhabitants of the other universes?

I see.

Well, goodbye, Professor.

And, er, good luck.

This is me suffering for science, or rather for my stomach.

I'm burning off the weight I put on in one wild day of eating,

trying to answer the question: Does fast food make you fat?

It tastes good, so you kind of get greedy for more.

Greediness makes you fat. I worked in fast food for three years.

Everything in moderation is OK for you.

It's so convenient, isn't it? Like, you can't be bothered to cook for yourself.

# I think of you and lick my lips.

# You've got the taste I can't resist Can't resist, can't resist... #

'As a bloke, I need around 2,500 calories a day.'

'If you're female, it's about 2,000.'

-Morning.

-Morning.

'But today, in the interests of science,

'I'm going to bust my limit with a Great British fry up.'

'Not exactly fast, but it ain't short on calories.'

-HE SIGHS

-OK. That was over 1,000 calories, just for breakfast.

'Who'd have thought it?

'That's almost half my day's calorie allowance gone in just one meal.

'But what exactly is a calorie?

'Well, it's the measurement of a food's energy.

'And, different foods have very different amounts.

'The trouble is, it's not always obvious how different, unless you set fire to them.'

Let's start with some fibre.

This is just a leaf of your common iceberg lettuce.

Whoa!

Big flame.

But it doesn't burn for very long.

So there's clearly not much energy in there, the lettuce is low in calories.

This is my weakness, salt and vinegar crisps.

Off it goes.

OK, this one's burning a lot longer

and that shows it's got a lot more energy inside it.

A crisp is, therefore, clearly much higher in calories.

'And that's mainly down to the F word: Fat.

'Fat is the most energy-giving foodstuff you can eat.

'And that's why this crisp, which is about a third fat, burnt way longer than the lettuce leaf.'

'And that's the thing with fast food.

'Weight for weight, it tends to contain much more fat than a far less tempting meal.'

That, plus breakfast, takes my tally to over 3,000 calories already,

and it's only lunchtime.

'The trouble is, it's so moreish.

'And that's because we've evolved to crave that mouth-watering mix of fat, salt and sugar,

'which is why we find fast food so tasty.

'Talking of which, time for dinner.'

So, this rounds off three meals in one day, that topped 7,000 calories.

'That's 4,500 more than I actually need.

'All of this excess energy will be stored as fat,

'over half a kilo of it if I don't burn it off.

'Fast food might make me fat, but exercise will sort me out. Won't it?'

Oh, man. That was two laps.

Lasted just over two hours.

But I only burnt 1,210 calories.

So, fast food doesn't technically make you fat, you know.

A calorie is a calorie. But, pound for pound, fast food contains more energy.

And, man, does it take a lot to burn it off!

# I want it, I need it Nothing else can beat it

# Hot and spicy Whenever I'm in town. #

FANFARE

BURPS AND FARTS

So, Australia's nice this time of year.

Slight problem on the cashflow front, though. No money for flights.

But, if you can't fly there, couldn't you just dig through the Earth and pop out down under?

# So follow me down I'll show you around

# There's a place we gotta go. #

OK, so I'm clearly not going to win any prizes for digging.

But, say, I had all my mates, a tunnelling machine, a digger, the full works,

could I then get to Australia?

'The trouble is, it's not just Tarmac and earth that stands between me and Bondi Beach.'

There's the little matter of the Earth's core.

And that's a problem, because it's hot.

For every 40 metres you burrow down,

the temperature increases by an average of one degree Celsius.

And Australia is over 10,000 kilometres away.

So you do the maths. You're going to be toast.

Down there, it's the same as the temperature on the surface of the sun.

But what if I lined my hole with a heatproof material so I didn't burn up?

Could I get all the way to Australia then?

Insulating a tunnel might sort out the heat problem.

But, unfortunately, there's a small matter of air pressure to contend with.

To find out more about this, I'm getting into this diving chamber

with diving specialist Simon Wilson

and an inflatable man called John.

Now, if you can imagine it, as you go deeper and deeper down your hole into the centre of the Earth,

there's more and more air above you.

The more air there is, the heavier it is, the more presses down on you.

And that increases the air pressure.

Now, rather than actually go deeper,

Simon is going to fill this chamber full of lots of air.

That's going to increase the pressure artificially.

OK. Let me know when you're good to go?

Let's do it, then.

Ooh, you can feel it straight away.

Whoa! He's going already.

Look at the state of that, look.

All the air around him is really high pressure.

So, it's pushing down. And it's really low pressure inside him.

It can't do anything. Just getting squashed.

And the reason that we're not doing that is because we've got fluid inside us

and that kind of pushes out and balances out.

It's getting really warm as well, really hot.

John's completely gone.

It's important to remember this. The air hasn't gone from John.

It's still in there, but it's just compressed.

-30 metres.

-30 metres?

SQUEAKY VOICE: Is my voice going higher?

HE LAUGHS

'We're now at such a high pressure, the way my vocal cavity vibrates has changed

'and my voice comes out at a higher pitch.'

I sound a bit like Donald Duck!

OK. That's the chamber at the bottom, about 50 metres.

'We're only a tiny fraction of the way to Australia.

The equivalent of 14 kilometres, in fact.'

-HIGH PITCHED VOICE:

-I just feel a little bit...drunk.

'And it's not just my voice that's gone weird.'

What you're experiencing is nitrogen narcosis.

-You're trying to make sentences.

-HE LAUGHS HYSTERICALLY

'Because of the higher pressure down here,

'I'm breathing in much more nitrogen gas than I normally would,

'and that really affects my nerve impulses.'

I can't take my voice seriously!

'I feel like I'm trashed, and I can't think straight.'

Pick up the chalk and do these four questions, OK?

7 x 6...

7... 14...

21... 33... Properly!

-HE LAUGHS

-35... 42, 42.

14, carry the 1.

1, 2...

34.

Write Australia backwards.

A, U...

A, U, S, T...

BLEEP!

A, U, S, T...

No, that's not right!

This is really embarrassing.

Australia. Is that right?

Our Australia cousins, it's USA Australia.

HE LAUGHS HYSTERICALLY

My brain doesn't work!

'So, at the equivalent of a mere 14 kilometres underground...'

I sound Australian in my head.

'..the intoxicating affects of all that nitrogen would have brought my dig to Oz to a premature end.'

'Time to go back up.'

Come on, John. Come back to us, John!

'And so he did. As the pressure decreased, the air in his body expanded.'

John has recovered.

'And restored him to his former glory.'

Look at that.

'And happily, I started making more sense too.'

How are you feeling, John?

So, what with the very high temperatures, extremely high pressures,

I don't think me and John are going to be digging to Australia anytime soon.

# Don't let me down, Don't let me down, don't let me down,

# I won't... #

Subtitles by Red Bee Media Ltd