...about Engineering James May's Things You Need to Know

Engineering is all about problem solving.

It's what chaps in hard hats do to improve our world,

using science and spanners and really sharp pencils.

So if you've ever wondered, "What did steam ever do for us?",

"How high can we build?" and "When can I move to Mars?"

then prepare to have your nuts tightened

as we find out the things you need to know about engineering.

Now logic dictates that we should start at the beginning. So...

Who were the first engineers?

We humans think we're pretty clever.

We've built megacities housing more than 30 million people,

skyscrapers stretching half a mile high,

and space-age materials strong enough to stop a bullet.

We are the planet's first and only engineers.

Or are we?

In fact, long before the Greeks or the Romans

even thought of putting one brick on top of another,

engineers were already hard at work all over the world.

Take a massive structure like the Hoover Dam.

Made from six and a half million tons of concrete,

it's over 1,200 feet wide, and holds back nine trillion gallons of water,

enough to flood the entire state of New York to a height of one foot.

But Canada has a dam twice as long, big enough to see from space.

And this one was built by...

..beavers.

Nature's been at it for a long time.

Civilisation is what, 10,000 years old.

Biology's been at it for 3.5, maybe 3.8 billion years.

So it's had the head start on us, and it will do for some time.

As for skyscrapers, African termites regularly build towers 30 feet high.

That's more than half a mile at human scale.

And they come with individual rooms and air conditioning.

With human engineering and Mother Nature,

there's like a completely different approach to the subject.

We try and come up with a concept.

We find a problem and we try and engineer a solution.

Whereas nature, her designs were much more random.

She took various paths, they failed,

and only the successful paths go forward.

And the wonderful thing about nature is you see all these amazing things

that have been produced by natural things going on

that have created amazing engineering.

OK, what about those bullet-proof jackets then?

It takes vats of acid, 700 degrees Celsius,

and a load of toxic by-products to produce Kevlar,

one of the toughest man-made materials.

An incy wincy spider's bottom, at room temperature,

produces silk that's five times stronger.

The point is, no matter how ingenious we become,

Mother Nature, the original engineer, almost always got there first.

SNEEZING

There is one engineering concept that we came up with all by ourselves.

With the exception of certain bacterial flagella -

that's microscopic bug-hairs to you and me -

the natural world is completely devoid

of something that we take for granted.

The rotary bearing, otherwise known as the wheel.

So, what first got us moving?

In engineering terms, the wheel is child's play.

Any toddler knows that the ones on the bus go round and round.

But how does the wheel actually work?

Looking at the engineering behind the wheel

is more complicated than you might think.

How the wheel works, good question. The more you think about it, the trickier it becomes.

For a reasonably simple device and concept,

the wheel's actually reasonably complicated to think about.

You try and think about the maths of it, you've got to be aware that,

you know, if you're drawing your... I'll need a piece of paper for this.

A wheel itself isn't a machine itself without the axle,

and all sorts of weirdness and then suddenly,

something Fred Flintstone should have been able to cobble together looks kind of complicated.

Without the wheel, moving heavy objects is a pain.

Literally, because the resulting friction means lots of effort,

but not a lot of result.

You could try using a lever, such as a crowbar.

This magnifies the force you apply, helping to overcome the friction.

But it won't win you any favours with the hippo!

Plonk him on a board, and add a few logs as rollers,

and you get rid of the friction completely.

Which is great, except for all that running back and forth

to replace the rollers. To get round this,

you attach them to the board.

And before you know it, you have an axle and wheels.

But instead of rolling, the axle rubs against its housing,

so now you've brought back the friction.

Luckily, though, the wheel's radius is much larger than the axle's.

It's basically a kind of circular crowbar,

continuously overcoming the friction.

Now, remember those logs? They got rid of friction altogether.

So let's put them back, only this time much smaller, around the axle.

Now you've got rid of the friction again,

and invented the modern bearing.

Which is great news for hippopotamus delivery guys everywhere!

Once we had the wheel, there was no stopping us, literally.

Not until somebody came up with the brake.

And, of course, somebody had to invent the road.

And even that was no good once you got to something like a river valley.

That gave the engineers another job to do.

They had to come up with the bridge.

So how do bridges work?

To understand bridges, we need to think about bats.

That's Beam, Arch, Truss and Suspension -

the four basic types of bridge.

A simple beam bridge is like a log across a river valley.

As it tries to support both your weight and its own,

the beam has to deal with two forces.

Tension, which stretches the lower surface,

and compression, which squashes the top.

But bring along too many of your gang, and,

suddenly, you need a truss.

A truss provides reinforcement by adding a bit more bridge

and harnessing the structural strength of the triangle.

The Romans preferred a more elegant and much curvier solution. The arch.

Actually, they probably nicked this idea from the Etruscans,

who never bothered to patent it, so that's their tough luck.

You can think of an arch as a beam bent into a semicircle.

Now the weight produces only compression. There is no tension.

Unless you happened to be an ancient Roman bridge builder.

They had to stand under their creations while the scaffolding was removed,

which might explain why so many of their arches are still with us.

A well-built masonry arch has simply no desire to fall down.

It's just not what it's going to do.

It has to break in at least three places before it'll collapse.

Which makes them very good for earthquake resistance

and kind of just general longevity,

which is why you see Roman and Saxon arches around now.

They just don't break.

Now, here's another way to build a bridge.

Flip an arch on its head and you get the suspension bridge.

This time it's all tension.

The overhead cables are in a constant tug-of-war

with the weight on the bridge.

It's exactly the same principle as your granny's washing line!

Speaking of washing, tackling this little lot would take forever

if it weren't for the miracle of steam.

But apart from allowing me to remove all the unsightly wrinkles

from these unmentionables,

have you ever asked yourself, what did steam ever do for us?

Steam is great for making frothy coffees, stripping wallpaper

and ironing socks. Preferably not all at the same time! SCREAMING

But engineers love steam because it's good at transporting energy.

When water is boiled, it absorbs heat, turning it into steam,

which can be piped under pressure to where it's needed.

Steam is a wonderful material because it can take heat energy

and transfer it from one place to another.

You start with heat and you can turn it into movement.

And ultimately, from movement, you can then turn it into electricity.

A further advantage of steam is that it's based around water,

which is largely everywhere. It's non-corrosive.

It's great, get some water, boil it up, create this vapour.

And then you can drive stuff.

2,000 years ago, a Greek chap called Hero invented the aeolipile,

a kind of steam-driven spinning ball.

Unfortunately, he only ever used it as a party trick,

and the idea sort of ran out of steam.

The ancient Greeks also had rudimentary railways called rut-ways.

So if our hero had thought to combine the two,

we might have had space travel by the Middle Ages,

and I'd have my hover-boots by now.

It was 1,700 years before steam powered its next revolution.

The industrial one.

The first practical design was the Newcomen Engine,

used to pump water out of mines.

But Scottish engineer James Watt wasn't impressed.

He realised that most of the steam's energy

was used up reheating the cylinder

after it was cooled during each cycle.

His external condenser worked outside the engine,

so the cylinder stayed hot, and more of the steam could be put to work.

The early beam engines, they used to inject the steam into the piston,

then cool it as quickly as they could

and it would suck the piston down and turn things that way.

The trouble was, the whole cylinder was cooled during the cycle.

James Watt, the Scottish inventor, then took the idea forward

and put an external condensing cylinder so that the cooling work

was done externally, leaving all the main heat in the cylinder.

And this dramatically increased the efficiency of the steam engine.

He marketed this by boasting how many horses it would replace,

which gave us the term "horsepower",

and kick-started the Industrial Revolution.

Today, power stations and nuclear submarines use steam turbines,

which are much more efficient than pistons and valves

and work on exactly the same principle

as our Hero's 2,000-year-old toy.

Impressive though the ships and locomotives of the steam age were,

there was one form of transport that would have to wait

for the internal combustion engine.

No, not the car, because they had steam-powered versions of those too.

I'm talking about the aeroplane.

So my next question is:

Fully loaded, the world's largest commercial aeroplane weighs 560 tons.

That's almost 50 London double-decker buses,

complete with passengers. And yet all that's keeps it aloft is thin air.

So thin, in fact, that it's unbreathable.

And the only thing between that and you

is less than half an inch of plexiglass!

Frankly, being at 30,000 feet is just plain terrifying!

Outside of the aircraft fuselage at 30,000 feet

is a pretty hostile place for a human body.

You're hurtling through the air at 500 miles an hour,

you're at temperatures of probably -60 degrees C.

There's very little oxygen at that sort of altitude,

so it's hard to breathe.

In World War II, some of the bombers flew at that sort of altitude.

So the crews would often get injured and/or die

just because of the hostility of the environment of high altitude.

It's not a place a person is supposed to be.

Even inside the plane,

the air pressure is kept much lower than at sea level,

which is a real pain in the ear.

It also means that water boils at just 90 degrees,

which is why airline tea tastes so horrible!

-Eurgh!

-To pressurise the air,

you have to pump air in using the jets on the plane.

And that uses fuel and it costs money.

So you don't take the full pressure of sea level pressure with you.

But you do pressurise them a bit

and they're pressurised to about an altitude of 9,000 feet.

And so every time a plane goes up to altitude and comes back down,

it gets stretched slightly and it shrinks slightly.

And it's a little bit like bending a paper clip.

You can only do this so many times before the thing starts to crack.

Meanwhile, at 500mph, a plane's windscreen has to be especially tough

to withstand the threat of bird strike,

which every year causes roughly 1.2 billion worth of damage.

To test their designs against the effects of bird strike,

the aeroplane manufacturers fire poultry at them

at speeds at up to 180mph from a giant chicken gun.

And all the time,

you are sitting beside up to 60,000 gallons of aviation fuel,

which, weight for weight, has 15 times the energy of TNT.

Given that commercial planes are struck by lightning

roughly once a year,

just be grateful that they're designed like huge Faraday cages

to keep you safe.

In fact, thanks to engineering,

air travel is reckoned to be 20 times safer than driving.

Aargh!

Oops!

I'm not afraid of flying, or at least, I wasn't,

but I am really terrified of those glass elevator things.

You know the ones that go up and down the side of a skyscraper?

Which is why my next question is,

how high can we build?

When it comes to tall buildings,

engineers have always played "who's got the biggest?"

This "edifice complex" led the ancient Egyptians

to build the Great Pyramid of Giza,

which, at 481 feet,

held the record for nearly 4,000 years.

Although today, it's 30 feet shorter thanks to erosion, and theft.

I'm pleased to report that it was an English building,

Lincoln Cathedral, that stole the title

of World's Tallest from the Egyptians,

a record it held onto for another 250 years.

Still not exactly what you'd call a skyscraper, though, is it?

It wasn't until the invention of the steel frame

that buildings really took off.

This carries all the weight of the structure,

but doesn't add much weight of its own.

So the glass walls of a modern skyscraper are really

just decorative curtains.

One problem skyscrapers regularly face is wind.

This can set up resonant oscillations,

causing a building to sway violently.

A single straight blow won't be enough to push the building down.

But if by freak chance, the wind happens to be

flicking to one side of the building and another,

at just the right rate to wobble it,

putting those pushes and pulls at the right times,

eventually the wobble on the building will build up

to such an extent that the whole thing will crash right down.

But change the shape of the building every few storeys,

and the wind gets confused.

So the diners in that top-floor restaurant

are less likely to lose their lunches.

At just over half a mile high,

the undisputed high-rise champion is Dubai's Burj Khalifa.

But Saudi Arabia is already planning the Kingdom tower,

the first to reach the one-kilometre mark.

That's almost seven Pyramids of Giza stacked on top of each other!

The very tallest towers require elevators that travel

at 40 miles an hour.

Keep going up at that speed and in 90 minutes you'd reach outer space!

Not everything in the engineering world is part of

this "mine's bigger than yours" game.

Far from it. In fact, the next big thing on the horizon

is positively, almost infinitesimally tiny.

So, what's so big about being small?

Please do not adjust your screen.

Things are about to get very tiny indeed.

Because nano-engineers measure things in nanometres,

or millionths of a millimetre.

If you were to scale a metre up to the size of the whole planet,

then a nanometre would be the size of this marble.

A nanometre is roughly what your beard would grow,

the length your beard would change, in the time it takes

to take a razor off the sink and towards your face.

A human hair is about 100,000 nanometres across.

Incredibly, that's 30 times bigger

than the working steam engine built recently by German scientists.

But 3,000 times smaller than that

is the world's first nanocar!

Made from a single molecule, its wheels would have to rotate

three million times to cross the head of a pin.

So it isn't going to break any speed limits.

The spherical wheels are made from one of the building blocks

of nanotechnology - the Bucky ball.

This new form of carbon was only discovered in 1985,

when it was created in the lab by accident.

Buckminsterfullerene, to give it its proper name,

can be stretched into a hollow fibre 100 times stronger than steel

and six times lighter.

Scientists predict that these materials may soon

lead to all sorts of minor miracles,

like self-replicating nano-machines that heal us from inside.

But altering things at a molecular level is risky.

If these man-made microbes were to multiply out of control,

they could devour all life on earth,

leaving behind nothing but a mass of grey goo.

Whatever you think of nanobots,

we all know that real robots are huge, awkward things

that speak in a dreary monotone.

A bit like politicians, really.

Except that robots are supposed to be clever.

So that leads me rather naturally to my next question.

Today we've got smart phones, smart cars, and even smart bombs.

But beside the world's top supercomputers,

these are distinctly dumb.

Here's a thought for you.

If my computer was as smart as me, would I be allowed to turn it off?

Or would that be murder?

In 2009, IBM built an artificial brain

with about nine trillion synaptic connections.

It needed a million watts of electricity,

and 6,500 tons of air conditioning gear,

and compared to the computing power of a human brain,

it measured an impressive 1% - about the same as a cat.

Intelligence isn't just about calculation.

It's about intuition, it's about knowing things.

It's about being able to understand things.

And I don't think computers are there yet.

They used to have a test question for artificial intelligence

that went along the lines of, "Time flies like an arrow,

"and fruit flies like a banana."

And no machine had any idea what you meant.

Supercomputing speed is measured in

quadrillions of calculations per second, called petaflops.

And the undisputed top of the flops is a Japanese machine called K,

which recently clocked up a cool 10.5 on the petaflop-ometer.

That's about 100,000 times faster than the average PC.

K runs the world's most advanced computer simulations,

virtual versions of everything from tomorrow's weather

to the entire universe.

But to be classed as truly intelligent,

a computer has to pass the Turing Test.

Basically, this is just a cosy little chat

using something like text messaging.

If after five minutes you didn't realise

you were talking to a machine, then it would pass

and win itself the Loebner Prize - 100,000,

plus a solid gold medal.

But, after 32 years, it is yet to be won.

Still, a little computing power goes a very long way.

Quite literally, as it turns out.

This small memory stick holds 100,000 times as much information

as the computer that powered NASA's Apollo moon missions.

Now that's what I call an engineering challenge.

So, how on earth did we get to the moon?

The total number of people to have set foot on the moon is 12.

Unless, of course, you believe it all took place in an aircraft hangar.

The half-million-mile round trip required a Saturn V rocket,

which stood 60 feet taller than the Statue of Liberty,

and had roughly six million components.

So even NASA's 99.9% reliability target

meant they could still expect 6,000 parts to fail.

The Saturn V is still the largest, most powerful rocket ever built,

and yet most of it had only one job -

to overcome earth's gravity by accelerating the small spacecraft

to 25,000 miles an hour -

faster than any human has travelled before or since.

What you're trying to do when you climb into a rocket

to try and travel to the moon

is escape from the gravitational bonds of the earth,

and that needs you to travel at 25,000 miles an hour.

That's seven miles a second.

Once you've got into space, the challenges continue to happen.

Because now you have to get from the earth orbit to a lunar orbit.

So you're orbiting the moon,

but then you need to land on the moon.

Apollo 11's Eagle touched down on the moon,

with just 20 seconds of descent fuel left.

But Neil Armstrong landed so gently

that the shock absorbers didn't even compress.

So his "one small step" down to the surface

was more of a three-and-a-half-foot giant leap.

And Buzz Aldrin had to remember not to lock the door,

because there was no handle on the outside.

When it was time to go home, just two-and-a-half hours later,

Aldrin accidentally broke the switch that started the ascent rocket.

With no tools on board,

they only managed to fix it by shoving in a ballpoint pen.

The Apollo missions were so incredibly far ahead of their time,

that the first man to walk on the moon

could have met the first man to fly.

When Orville Wright died in 1948,

Neil Armstrong was already nearly 18 years old.

But it's been 40 years

since a man last dirtied his boots with moon dust.

What I want to know is -

Looking for a new place to live?

Our solar system has dozens of vacant properties.

But by far the most desirable is Mars.

Right now, you can buy an acre of Martian real estate

for less than the price of a decent haircut, whatever that is.

But just how suitable a home is the Red Planet?

For starters, it's not too far away.

Sometimes as little as 36 million miles.

So you'll be there in just six months.

Going to the moon is like popping to the shops,

compared with Mars which is more like a trip

across the entire Atlantic.

And for those two journeys, you would prepare quite differently.

One you could do in your slippers, almost.

Mars has days, seasons and weather, all similar to earth's.

Admittedly, the atmosphere is a little thin and lacking in oxygen.

And it can get a bit chilly,

around minus 130 degrees Celsius at the poles.

There's no oxygen, there's terrible sandstorms,

it's very corrosive and it's very cold.

So it's not a great holiday destination at the moment.

But with some TLC and a little hard work,

Mars could make an ideal second home.

It's called terraforming, and the goal is

to thicken the atmosphere and raise the temperature.

It might sound like science fiction,

but real-life engineers are working on it right now.

One idea involves giant space mirrors,

reflecting enough sunlight to melt the ice caps.

This would release water and carbon dioxide

to kick-start global warming.

Another suggests building solar-powered factories

to produce those greenhouse gasses.

Or, how about redirecting a few passing asteroids

and crashing them into the Martian surface?

Each impact would release enough energy

to raise the planet's temperature by three degrees.

But according to some estimates,

all this could take as much as 100,000 years.

So instead of changing Mars,

it might be quicker to change ourselves.

Maybe things aren't so bad here on earth after all.

I mean, I know we've got our problems,

but at least we stand a fighting chance of sorting them out,

thanks to the brilliance and ingenuity of our engineering.

Has anybody got a screwdriver?

Screwdriver?

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