0:00:02 > 0:00:04'Animals are amazing.'
0:00:04 > 0:00:05That's astonishing!
0:00:05 > 0:00:07'And the more we find out about them,
0:00:07 > 0:00:10'the more amazing they seem.'
0:00:10 > 0:00:11That feels pretty harsh.
0:00:11 > 0:00:13'That's why scientists all over the world
0:00:13 > 0:00:17'are trying their best to copy them...'
0:00:17 > 0:00:18This is the future.
0:00:18 > 0:00:19'..making brand-new inventions...'
0:00:19 > 0:00:21Tomato juice.
0:00:21 > 0:00:23'..based on what animals can do.
0:00:23 > 0:00:25'Some are astounding...'
0:00:25 > 0:00:27We've just dived under the sea!
0:00:27 > 0:00:28'..some bizarre...'
0:00:28 > 0:00:30This is not at all pleasant!
0:00:32 > 0:00:34Yes, it's gone!
0:00:34 > 0:00:39'..but they're all inspired by the miracles of nature.'
0:00:41 > 0:00:43Episode seven.
0:00:43 > 0:00:46How your computer could be quieter
0:00:46 > 0:00:50by taking a lesson from birds.
0:00:50 > 0:00:52WAVES CRASH
0:00:53 > 0:00:56This place is very special.
0:00:58 > 0:01:01At about this time of year once, maybe twice, a week,
0:01:01 > 0:01:05a unique phenomenon occurs, almost within touching distance.
0:01:05 > 0:01:09And that's why, although this beach is far from easy to get to,
0:01:09 > 0:01:12it draws fascinated onlookers from all over the world,
0:01:12 > 0:01:16each hoping to see and hear something they'd be very unlikely
0:01:16 > 0:01:19to encounter at such close quarters anywhere else.
0:01:23 > 0:01:26And it's something that's going to happen any moment now.
0:01:27 > 0:01:30All we can do is watch and wait.
0:01:39 > 0:01:40This is it. Here it comes.
0:01:40 > 0:01:43'Not a natural phenomenon at all,
0:01:43 > 0:01:48'but the weekly arrival of flight 785 from Amsterdam.'
0:01:48 > 0:01:50All here to see this. I know!
0:01:52 > 0:01:56'Because here, on this very beach, you can get closer
0:01:56 > 0:02:01'to a landing jumbo than practically anywhere else on the planet.
0:02:01 > 0:02:04'And it's an ear-splitting experience.'
0:02:04 > 0:02:06PLANE ENGINE GROWS LOUDER
0:02:06 > 0:02:09Now, believe it or not, most of that noise comes not from
0:02:09 > 0:02:14the plane's engines, just from the wind rushing around the aeroplane.
0:02:14 > 0:02:16In other words, turbulence!
0:02:18 > 0:02:20ENGINE ROARS
0:02:23 > 0:02:25A lot of it!
0:02:28 > 0:02:30I mean, a lot!
0:02:30 > 0:02:36That turbulence is generated every time a plane pushes through the air.
0:02:37 > 0:02:41But surely there has to be a quieter way to fly?
0:02:45 > 0:02:49There is one creature which, despite having a top speed
0:02:49 > 0:02:54well in excess of 30 mile an hour, is virtually silent.
0:02:54 > 0:02:59Somewhere around here is one of those creatures
0:02:59 > 0:03:02that's been specially trained to go into a hunting mode
0:03:02 > 0:03:04when they hear this noise...
0:03:04 > 0:03:06- MACHINE BEEPS - ..that's coming from that
0:03:06 > 0:03:09beeper down there, being operated by this button in my hand.
0:03:09 > 0:03:11So, here's the set-up. I'm going to lie down here,
0:03:11 > 0:03:14with the beeper hidden next to my head,
0:03:14 > 0:03:16and sound it.
0:03:16 > 0:03:19My job is to try and take a photograph of the creature
0:03:19 > 0:03:21as it attacks.
0:03:21 > 0:03:24But to make that just an extra little bit tricky,
0:03:24 > 0:03:27give me more of a challenge, I shall be blindfolded.
0:03:28 > 0:03:33So, really all I can do is listen for my attacker.
0:03:34 > 0:03:35Right.
0:03:35 > 0:03:39Well, let's get started. I am now the prey.
0:03:39 > 0:03:42MACHINE BEEPS
0:03:42 > 0:03:45'Time to summon my trained attacker.'
0:03:48 > 0:03:50It's surprisingly tense.
0:03:50 > 0:03:52MACHINE BEEPS
0:03:52 > 0:03:56If the creature appears, I've got nothing but my ears
0:03:56 > 0:03:59to warn me of its approach.
0:04:02 > 0:04:05MACHINE BEEPS
0:04:15 > 0:04:17MACHINE BEEPS
0:04:19 > 0:04:22And this is that creature -
0:04:22 > 0:04:24a barn owl.
0:04:33 > 0:04:34GRASS RUSTLES
0:04:34 > 0:04:36CAMERA CLICKS
0:04:38 > 0:04:42Wow, that was genuinely amazing.
0:04:42 > 0:04:44When somebody tells you something like,
0:04:44 > 0:04:46"A barn owl can fly silently,"
0:04:46 > 0:04:51I generally take it with a pinch of salt, but trust me, they can.
0:04:51 > 0:04:55I had no idea she was there until she hit the ground.
0:04:58 > 0:04:59Totally silent.
0:05:03 > 0:05:07It's a massive advantage for owls to be able to fly so quietly.
0:05:10 > 0:05:13Firstly, so their wings operate silently enough
0:05:13 > 0:05:17that they can still hear the sound of any possible prey.
0:05:19 > 0:05:24And secondly, so that their prey can't hear them.
0:05:25 > 0:05:28But to see what makes owl flight so special,
0:05:28 > 0:05:30we need a little experiment.
0:05:33 > 0:05:36Starting with this pigeon.
0:05:41 > 0:05:45Just watch what happens when it flies across a bed of feathers.
0:05:51 > 0:05:53That is turbulence in action.
0:05:57 > 0:06:01Now here's an owl attempting the same thing.
0:06:08 > 0:06:11There's almost no disturbance at all.
0:06:14 > 0:06:16But how on earth is it doing it?
0:06:18 > 0:06:23Well, it turns out that owl wings have three very special features.
0:06:23 > 0:06:27These tiny knobbly teeth stop the front edge creating
0:06:27 > 0:06:29one big whirlpool of air.
0:06:31 > 0:06:35Then a layer of soft, velvety feathers keeps
0:06:35 > 0:06:37that airflow close to the wing.
0:06:37 > 0:06:42And finally, that tattered back edge reduces turbulence
0:06:42 > 0:06:45as the air leaves the wing.
0:06:47 > 0:06:54So I thought, what if I could make an airplane wing like an owl's wing?
0:06:55 > 0:06:58I've had to improvise a bit, with materials and such,
0:06:58 > 0:07:00but that's how it is with science.
0:07:00 > 0:07:02And here it is. It's got everything.
0:07:02 > 0:07:06The egg boxes give the leading edge that knobbly profile,
0:07:06 > 0:07:08to break up the airflow into smaller vortices.
0:07:08 > 0:07:10The carpet, the texture,
0:07:10 > 0:07:14breaks up the huge bubble of disturbed air and reduces noise,
0:07:14 > 0:07:16and the trailing edge is serrated,
0:07:16 > 0:07:18and that cuts down on noise, as well.
0:07:18 > 0:07:21So, why don't all aeroplane wings look like this?
0:07:23 > 0:07:26Well, it turns out it's not that simple.
0:07:28 > 0:07:31The problem is one of scale.
0:07:32 > 0:07:35That amount of egg boxes and carpet
0:07:35 > 0:07:39would just slow the plane down too much.
0:07:39 > 0:07:42And the serrated lino would apparently
0:07:42 > 0:07:45get in the way of the flaps they use for braking.
0:07:48 > 0:07:49But all is not lost.
0:07:53 > 0:07:57It turns out there are smaller wings that would benefit
0:07:57 > 0:07:59from owl technology.
0:08:00 > 0:08:04It's just that they're attached to fans.
0:08:07 > 0:08:11And that might turn out to be even more important.
0:08:22 > 0:08:26OK, so a silent fan might not sound as exciting as
0:08:26 > 0:08:30a huge, furry aircraft wing, but bear with me,
0:08:30 > 0:08:33because silent fans would make a bigger difference
0:08:33 > 0:08:34than you might think.
0:08:34 > 0:08:36FAN GOES SILENT
0:08:36 > 0:08:38Imagine silent computers, silent hairdryers,
0:08:38 > 0:08:43silent vacuum cleaners, silent wind farms, silent air conditioning.
0:08:43 > 0:08:48Because all those fans suffer the same sort of problems
0:08:48 > 0:08:50with turbulence that planes do.
0:08:53 > 0:08:57So, the inventors of this fan have used owl tech to break up
0:08:57 > 0:09:01that turbulence, by adding serrations to the back edge.
0:09:03 > 0:09:10And the result is a fan that is very, very quiet indeed.
0:09:12 > 0:09:15No matter how hard you listen.
0:09:20 > 0:09:24So, this owl technology, copied directly from the way
0:09:24 > 0:09:27a barn owl protects its super-sensitive hearing
0:09:27 > 0:09:28from wind noise,
0:09:28 > 0:09:33could end up making our noisy world just a little bit quieter.
0:09:33 > 0:09:37At least until the next plane comes along.
0:09:37 > 0:09:38PLANE ENGINE ROARS
0:09:38 > 0:09:43A silent fan based on the way an owl flies.
0:09:43 > 0:09:47One of the quietest miracles of nature!