Episode 2 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 who 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 going to 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.

'This time on The Secrets Of Everything...'

'..I'll be finding out why chillies burn...'

I'm shaking!

'..even when they're cold.'

This is exactly what makes fires burn so well.

'My friend Doc and I will be discovering

'why fire doesn't always burn, even though it is hot.'

-Is your hand heatproof or something?

-No, my gloves are.

'And we'll be exploring what happens after we die.'

The smell is just so rank that I can no longer stand it.

But first, I'll be finding out

if there's any truth to one of our favourite urban legends.

So, you're at the top of an office block and you take the lift

because you can't be bothered with the stairs.

But something's wrong. You're going down, but far too fast.

SCREAMING

What do you do? You remember hearing someone say

that if you jump at the last minute,

you can survive your perilous drop.

But is it true?

'It's time to put the legend to the test

'with the help of a crane, a portaloo...'

This is our willing lift drop volunteer.

'..and our body double.

'We're dropping him from 30 metres up...'

All set?

'..to see what would happen if you did nothing at all.'

Three, two, one.

Ooh!

Oh, that looked painful!

-Oh, dear. That's not good.

-That's not good.

God, if that had been me in there, I would have lost both feet.

My ankles have completely gone.

That is one mangled foot.

Looks like if you stand in a falling lift, the force of the impact

goes straight through your feet and up through your body.

We're going to need another dummy.

So the legend says if you jump at the last minute, you'll be fine.

'Time to put it to the test.

'We've rigged up a spring-loaded platform

'to make our synthetic stuntman jump

'just before he hits the ground.'

Three, two, one.

-You've done it.

-Ooh!

Look at that. Let's get in.

Look at the state of his feet.

It's still complete and utter...

-That's bad.

-Broken man, isn't he?

Even though our man jumped at the last minute, he was still travelling

earthwards quicker than his jump was pushing him up.

So if you do find yourself in a falling lift,

you can try and jump, but it will make such a minor difference

to the speed you're falling.

Plus, you don't have a glass bottomed lift,

so you won't know when to jump.

There is no truth to that urban legend.

BELCHES

Now, there's one thing that's always got me.

If chillies are cold, then why on earth do they burn?

It's probably because I am a total wimp when it comes to eating this.

And it seems it's not just me.

So spicy, I felt like I was hallucinating.

-Stuck on the toilet for about 20 minutes.

-Yeah, not good.

It made me sweat profusely.

Then it just came out the other end really quickly.

I had jalapeno on a pizza and it made me fart.

It hurt going in and then it hurt coming out.

'To answer this, I've challenged my mate Johnny

'to a chilli-off. 'Johnny makes the hottest food I've ever eaten.

'But today, I'm pushing him to the limit.'

Right, dude. This is it. Look at the state of these.

-So I'm thinking we need to make this a proper competition.

-Yep.

I'm thinking money where your mouth is.

The strength of a chilli is measured on what's called the Scoville scale,

ranging from zero, with no heat,

up to a tongue-splitting one million and beyond.

And I've lined up these seven beauties

to see who can handle the heat.

Right. Easy, impossible.

-Ready for it?

-I'll give it a shot.

-OK.

-That's all right.

-Sweet.

That's because that one is just a bog-standard, normal bell pepper.

Bell peppers register on the Scoville scale at zero. Pathetic!

Let's go on to the next one.

Jalapeno, 2,500 on the Scoville scale.

-OK.

-Are you ready?

-I'm game.

-HE COUGHS

-That's hot.

'Jalapenos have raised the bar and the infrared camera clearly shows

'my face burning up.

'But how come the chilli itself stays a cool blue?

'It's not the temperature of the chilli that matters,

'it's all to do with a cheeky chemical called capsaicin.

'To get at it, I've ground up the pod

'and soaked it in vodka.'

Now, not all chillies have the same amount of capsaicin in them.

The hotter they are, the higher the concentration...

'and the higher they register on the Scoville scale. Talking of which...'

Oh, man!

There's a kick in the background. It's fizzing under my tongue.

I'm just getting a tongue of fire.

It's like I've eaten a hot coal or something.

'All sensations, touch, taste, smell,

'start their journey to the brain from nerve endings.

'In this case, on my tongue.'

Each of these nerve endings has a receptor,

acts a bit like a valve, like this.

When it's stimulated by, say temperature, the valve opens

and a message is sent to the brain

telling it how hot that thing is.

Now what capsaicin does is it lubricates the valve,

making it a lot more sensitive.

The result is that even a small temperature

that wouldn't normally be registered sends a strong signal to the brain.

Your body thinks it's being physically burnt,

even though there's no heat there.

This one is an orange habanero.

Oh, man! That is a killer.

Oh, gosh!

Every time you swallow, it's like...

It's like someone is actually cutting your tongue.

'Even though it feels like there's a bandito

'with a knife in my mouth...'

Ah! Ah! Ah! Ah!

'..the chilli isn't burning me at all.

'It's just those lubricated valves

'screaming at my brain that I'm on fire.'

And scientists reckon the body tries to cool down by sweating

and increasing its heart rate.

-That IS burning!

-Dude, you've gone redder than the next one.

Moruga, at a cool half a million

on the Scoville scale.

Go.

Oh, God!

Ah!

Ah, ah!

-That is... I can't even talk.

-I need a scotch egg to go with this.

I can't talk! I'm out, I can't go any further.

I can't talk. I'm going to vom.

'Johnny's on his own now,

'but what he doesn't know is that the last one

'is one of the hottest chillies in the world.'

That...

..is a Spanish Naga,

one million on the Scoville scale.

You going to do it?

I'm going to give it a shot.

I'll give it a shot.

Three, two, one...

-OK, I'm shaking.

-Go!

Come on, come on.

Chew, chew.

How is it?

Erm...

That's, er...

HE LAUGHS

That's hot!

Put it there.

Well...

It was a valiant effort.

My...my stomach will never forgive me.

-I think you win this, my friend.

-Thank you.

I'll leave you to recover.

'The fact is, chillies aren't hot at all.

'It's just the capsaicin that tricks you into thinking they are.

'So next time you're up against a serious vindaloo,

'remember - it's all in the mind.'

It's not a particularly pleasant thought, but the only thing

that's certain with life is that we're all going to die

and when that happens, that's it, I'm gone.

Greg Foot has left the building.

But my body will stay here and I'll just be like any other bit of meat.

So what I want to know is how long does it take

to decompose when you die?

There are lots of things that I'll do in the name of science,

but I don't want to rot just yet.

This poor individual who died of natural causes

just a few hours earlier makes a pretty good stunt double.

So a pig would be really good for our tests to see how long it takes for a human to decompose?

The size is about the same, their skin is really similar to humans,

they've got the same kind of muscle to body fat ratio

and their general physiology is quite similar to humans.

It's as good a substitute for a human as we can get, really.

Apart from the snout and the trotters, I suppose.

To find out what happens to our bodies once we've pegged it,

we're going to film this pig's decomposition 24/7.

Although this is a fresh corpse, the pig is changing by the second.

I thought it went stiff pretty quick.

What you're talking about is rigor mortis,

which is contraction of the muscles.

It begins about three hours after death.

Let's leave him and see what happens.

To protect our pig from scavengers, we've covered him

with a shelter and netting.

But this doesn't stop the flies, which arrive almost immediately.

Soon after, the pig's body is bloated with gases

from its rotten flesh. Just a few days later,

the corpse is riddled with maggots.

There's not much left of it now. That is... That's pretty rank.

The corpse has just been through a process called autolysis,

that's where the cells are broken down by their own enzymes.

It's like the body is digesting itself.

It looks like it's burst or something.

Yeah, that's pretty much what's happened. First of all,

it bloated with the build-up of gases inside it, and then the body tissues

have liquefied and purged out.

'And once this happens, the dinner bell rings for these beauties.'

There were flies coming almost immediately

and that's what's led to the maggots, right?

They laid their eggs almost immediately in the natural orifices,

like the eyes and the snout. The eggs will have been hatching

out into maggots and the maggots will be eating the body tissues.

'They might be revolting, but maggots can be key witnesses

'in murder cases. By working out how old the maggots are,

'pathologists can calculate the victim's time of death.'

What's all that stuff? It's all wriggling!

That's liquefied body tissue that has then been agitated

by the movement of the maggots, that's why it's kind of foamy.

It's getting to that stage...

It really is getting to that stage

where the smell is so rank that I can no longer really stand it

and I'm going to vomit.

-You've reached your Waterloo.

-I think I have.

# I just dropped in

# To see what condition My condition was in

# Yeah, yeah, oh, yeah

# What condition My condition was in. #

Oh, here it is.

-Yep, in all its glory.

-And it doesn't smell as bad.

-Not as bad, it still...

Although you can still, you still get it

-at the back of the throat.

-Yeah.

-Just a bit of rank.

It's pretty gruesome to think that this is what would happen to us

if we were left to the mercy of nature.

But what if we were six foot under?

Well, burial creates quite a few different conditions.

For example, the temperature, that's the most important factor. It's much cooler,

and the access by insects is reduced dramatically.

And how long would my bones be there for?

That depends on the soil conditions, but hundreds of years.

So it looks like there's no definitive answer

for how long it takes a human body to decompose,

but it is all great gruesome stuff and if one thing's for certain,

your bones are going to be around for a very long time.

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.

Professor Logic is going on a journey.

What are you hoping to discover today, Professor?

You're going to measure the world to find the shortest route around it.

Professor Logic, is this strictly necessary?

I mean, can't you just use a formula like 2 x Pi x r or something? No?

Well, no, I suppose that would mean

that you knew what the radius of the world was already.

I can't see much measuring going on.

Oh, I see. You're measuring angles.

Because you know how high the mountain is

and you've measured the angle between the horizontal and the horizon,

you can work out the ratio of the world...using that formula.

And now you can use 2 x Pi x r.

But there's a problem because the earth is not a perfect sphere.

It's 40 kilometres wider than it is tall.

So if it bulges in the middle, the quickest way around the world

would be top to bottom and back up the other side.

That's mainly sea, Professor Logic.

Wouldn't it be a rather lonely voyage?

So what is the shortest distance around the world?

Professor Logic, how far?

Thank you very much.

No, no, pleasure's all mine.

# It's the end of the world As we know it... #

Space is dangerous. Cold, dark

and rammed full of asteroids ready to plough into the earth.

If one did, could you survive?

What would I do to survive if an asteroid hit the earth?

-Where's it going to hit?

-London.

-Leave.

I think I'd take everything from Primark that I could.

-I'd probably become a lot more religious.

-Start running?

-Yeah.

I don't think there'd be a lot I could do to survive

but there'd be a big cloud of dust

and it would get very cold very quickly.

The earth and the moon are sitting ducks in the cosmic shooting gallery.

The moon bears the bulk of the battle scars but, according to NASA,

over one million objects still hurtle towards our planet every day.

These objects can be anything

from planet-sized asteroids a few hundred kilometres across,

to tiny specks of dust, or even smaller fragments this sort of size called meteoroids.

A golf ball is never going to destroy the planet

but the thing about asteroids and meteoroids

is that they travel unbelievably fast,

which gives them massive amounts of potentially destructive energy.

I can work out how hard or with how much energy

a golf-ball-sized asteroid will hit the ground using this formula.

Now, E is for energy, so energy is a half times the mass.

Now, the mass of that size lump of rock is about 50 grams,

which is 0.05 kilograms

and the speed, well, the speed of an average asteroid

is 30,000 metres per second.

30,000.

Now that is 67,000 miles per hour, which is just mind boggling

when you think that the fastest bullet goes about 2,000 miles per hour,

which is pretty rubbish in comparison.

Now you square that, which means times it by itself,

treble the number through

and that comes out at 22.5 million joules of energy.

That is a massive number.

To get some idea if we could survive even a golf-ball-sized asteroid impact,

I've asked a pyrotechnics expert

to turn my maths into an instant meteor strike.

Mike's worked out that we need five kilograms of high explosives,

so that's what we're burying.

So just about there.

-I think this is deep enough.

-Great. Perfect, perfect.

-Cool. What's next?

-Right. Now we have to bury this.

-OK.

-And connect it up to the igniter.

-All right. How far do we have to go?

-Around 400 metres.

-Wow, 400 metres?

-Yeah.

It'd better be a big blast to see it from there.

-All ready and set to go.

-Over to you.

-OK. Three, two, one.

Wow, that is an explosion.

That is cool. Wow. Can I...

-Is it safe?

-Go for it, yeah.

-Can I go down?

-Yeah.

Wow!

That is a cracking crater.

That's like three metres across.

And this would be caused from just a small piece of space rock.

If you had something even about five metres across,

that would give the equivalent amount of energy

to 15,000 tonnes of TNT,

which is like the atomic bomb

that was dropped on Hiroshima in World War II.

So why doesn't the earth look like someone's taken a shotgun to a watermelon, like the moon does?

It's because of something that we have that the moon doesn't,

an atmosphere.

Check this out, all I've got is a cylinder full of air

with a little bit of cotton wool at the bottom, that's it.

How cool is that?

When the plunger goes down, the air molecules are squashed together.

With all of them rammed into a tiny space, there are more collisions

and the temperature shoots up enough to ignite the cotton wool.

Just air and cotton wool, no flame, and you get fire.

The same thing happens to asteroids as they hit the earth's atmosphere.

They are travelling so fast that the air in front of them is compressed

and heats up to over 1,600 degrees Celsius,

hotter than molten lava, and the asteroid simply burns up.

In fact, the atmosphere is so good at protecting us,

only asteroids larger than 35 metres across

stand any chance of getting to the ground at all,

which is why there are plenty of shooting stars in the sky

but hardly any asteroid craters on earth.

So for asteroid Armageddon to play out you need a very big rock indeed.

But an asteroid is not likely to kill you

because NASA know where all the largest near-earth asteroids are

and there isn't one on target to hit the earth in your lifetime.

Or your children's lifetime.

Or your children's children's lifetime.

Or your children's children's children's...

AIR RAID SIREN

It's one of mankind's oldest discoveries - how to make fire.

And even today, it's got a sort of ethereal quality to it,

an allure.

But what is a flame? And why does it burn?

# We are fires in the night. #

What I need to help me is a fire-starter.

A man who is a chemist, practical engineer, meteorologist

and...Polish musician?!

He is Dr Zbigniew Szydlo.

I just call him Doc.

-Today.

-Yep.

-I want to explore fire and flames.

-Right.

What do you want to show with these flames - smoke, heat, rapid combustion...?

-I want some big flames.

-Some big flames?

-Some momma flames.

To get a really good fire going, you need three things.

You need a fuel to burn and that's what the woodchips are,

you need heat to get the whole thing going and you need oxygen,

which is what we're blowing in here, so we've got a nice supply of it.

And the more oxygen there is, the quicker the reaction happens.

-Is your hand heat-proof or something?

-No, my gloves are.

You need training and experience to pull this off, and Doc's got plenty.

But don't try this at home.

Liquid oxygen is a thousand times as concentrated as gaseous oxygen.

This is exactly what makes fires burn so well. Allow me.

So that's that lethal combination of fuel, heat and oxygen.

What's happening between oxygen and wood

is a plain and simple chemical reaction,

which releases heat and light energy at the same time.

It's the heat of the reaction that causes the gas to be so hot that it glows.

But if fire is so hot, then how can I do this?

We all know that fire can kill, so how come it's possible

to touch flames without getting burnt? To find out,

I'm going to set my soles on fire.

This is now off my scale,

which means parts of this fire are over 700 degrees. Yeah, that's kind of hot.

Walking barefoot across hot coals is a risky business,

but I'm hoping

that knowing the science of how flames burn might work in my favour.

If you take a balloon, pop it over a flame...

Yeah, it bursts.

But if you take one full of water and you hold that over the flame...

..this time, it doesn't burst.

The water has absorbed the heat

and protected the balloon from bursting, up to a point.

It's a really simple bit of science, but I've got to use that

if I want to get across the coals without burning myself.

My body is made up of about 73% water

and, like we saw with the balloon,

as I walk across this,

the water should absorb the heat rather than my skin.

Theoretically, each foot should be able to touch the coals for about a second

before the damage kicks in.

So despite being protected by my water content,

if I don't get across quick enough, I could get badly burnt.

Oh, that's warm!

Yes!

Yeah!

That was amazing.

It just goes to show, it is possible to play with fire

and not get burnt if you understand the science.

There are still loads of secrets out there. Next time...

can sound kill?

I want to see the effect of sound on these massive pig lungs.

Will this girl kill me?

She's hard as nails.

And will drinking your own body fluids kill you?

Bottoms up.

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