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  • - ( music playing ) - Dan: We're here for the fun silly wave.

  • That's correct, yes.

  • Okay, all right.

  • Gav: It looks like someone's just

  • pulling on space time.

  • - ( grunts ) - Not really sure what I'm looking at.

  • Dan: Bath time.

  • Gav: Those ducks just went--

  • Dan: Whoosh!

  • Gav: How do you feel about taking it

  • right in the face?

  • Gav: Dan, are you nervous?

  • - Oh. - ( water splashing )

  • - Gav: ( chuckles ) Oh! - ( laughter )

  • Well, that was a very unique

  • building we had access to there.

  • I love the fact that they just let us

  • mess around with it.

  • It's this incredibly scientific and precise

  • equipment and they were like, "Go wild."

  • Your life jacket going off,

  • unexpectedly, almost wet myself.

  • I think I even said, I was like,

  • - ( chuckles ) - "Huh, I'm surprised

  • this hasn't gone off."

  • and then about two seconds later it--

  • - ( air whooshing ) - Both: Whoa!

  • Both: ( laughing )

  • I think they're activated by salt

  • aren't they? Like it dissolves and

  • - then it activates-- - Yes, the salt in there

  • to make salt crystal, yeah.

  • Did it hurt taking the spike wave in the mouth?

  • - ( water splashing ) - Ooh!

  • Dan: I thought it was going to,

  • but it actually didn't.

  • I really liked that shot where

  • - ( music playing ) - it sort of tunnels

  • around your face, you look like you're

  • in a weird room that's moving.

  • Dan: Totally surreal. No one had done

  • that before, it was quite an honor really

  • to be the first smashed in the face with it.

  • Gav: Yeah.

  • So I think it'd be a good idea

  • if we learned more about waves in general,

  • but also learn a little bit more about the facility.

  • So we had a little chat with Tom.

  • Dr. Thomas Davey, you're the Senior Experimental Officer here.

  • Yeah, that's correct, yeah.

  • Okay, so, you can tell us all about

  • what you do here essentially.

  • Yes, so this is a facility which essentially is

  • just a model sea, about 20th scale.

  • And we we use that for lots of applications,

  • testing things like wave energy devices,

  • tidal energy devices.

  • Basically anything which we put in the sea.

  • Okay, so if you make a small wave about this big in here,

  • you imagine it's 20 times the size.

  • That's what you're imitating essentially in the ocean.

  • - Dr. Davey: Exactly. - Dan: So how long did it take to fill that thing?

  • Uh, it did take us three weeks, so--

  • - Three weeks? - ...we don't like taking the water out of it.

  • It's two and a half thousand tons of water in this tank.

  • And what was the choice behind making the tank

  • this specific size?

  • If you go much bigger,

  • things start to get very expensive.

  • If you go much smaller the scaling

  • will start to work against you, uh...

  • - I imagine this was cheap, then. - ( laughs )

  • Yeah, so you're looking at

  • about 6 millions pounds of investment

  • just to build the tank.

  • And actually the whole project's probably around

  • 12 to 15 million.

  • Might be one of the more expensive things

  • - we've messed around with... - ( laughs ) Yeah.

  • ...if I'm honest. Cool.

  • So how do you get the waves to do

  • the exact thing you want them to?

  • Well, this is the only large circular wave

  • and tidal tank in the world.

  • So what we have is 168 wave makers around the edge.

  • These are basically paddles.

  • So each individual paddle on its own can generate a wave.

  • But because we're in a circle,

  • you can imagine, you can actually then generate from any direction,

  • so you can have this one wave going in one direction,

  • you can have thousands of waves going from all directions.

  • It's a bit like playing a musical instrument.

  • You just combine all these notes together

  • to create a very complex sea in the tank.

  • - Whoa-ho-ho-ho! - Whoa!

  • ( water splashing )

  • And then on top of that you then put tidal currents.

  • So you make currents as well underneath...

  • Dr. Davey: Yes, yes. It works a bit like a conveyer belt.

  • The current comes from underneath the tank,

  • over the top, and back around again.

  • - Oh, okay. - So...

  • You said you can replicate any part of the sea.

  • If I said to you, I want to replicate Brighton.

  • I want Brighton, could you do that for me?

  • As long as you got the data.

  • If we could get good data for a site

  • and we can understand the energy of that site

  • and the directions of the waves and so on, then yes.

  • That way, if you just brought in a load of sand,

  • and people didn't fancy the, like, eight hour drive,

  • you could have people just come in here

  • - and enjoy the-- - Yeah, we'd be in the surfing business.

  • ( laughter )

  • Thanks, Tom, that was really interesting

  • and thanks for letting us use your very expensive pool.

  • Dr. Davey: No problem.

  • Back to you, Gav and Dan.

  • Thanks, us.

  • Why don't we learn some more about waves.

  • Yeah, we've invited someone along

  • who's travelled the world,

  • and written a book about all the world's

  • scariest, largest, fastest waves.

  • It's called "Tides."

  • Hi, Jonathan. How's it going?

  • - Hi, Dan. - Hey.

  • Could you explain to us, the difference between waves and tides?

  • Sure, waves, as we talked about

  • are generally created in the storm, right?

  • There's a one pulse that makes the wave

  • and then the waves travel away from that.

  • But a tide is actually also a wave,

  • but it's the largest wave on the planet.

  • And it's a long low wave

  • that travels about 450 miles per hour around the globe.

  • We don't experience it as a fast moving phenomenon

  • because if we're on the coast, we have to stay there all day

  • to watch it pass, right?

  • Six hours of trough, which is low tide,

  • and then about six hours later, the crest, high tide.

  • So you could potentially be on a plane,

  • unknowingly flying at the same speed

  • - as a tide rolling through. - That's right.

  • The oceans actually aren't deep enough

  • for this free wave, this wave of tide, to travel

  • as fast as it wants to travel.

  • So essentially it drags its legs

  • on the bottom of the ocean,

  • and slows down and creates friction.

  • Friction against the entire Earth?

  • - That's right. - Wow, yeah.

  • 'Cause I've heard that they occasionally

  • will add like a leap second to the clocks

  • to compensate for the Earth slowing down.

  • Tides have literally slowed down the rotation of the Earth.

  • Acted as a break.

  • 'Cause the tides are slowing down the world

  • by friction on the bottom of the sea.

  • That means every millions of years,

  • there's changes to the amount of hours in a day?

  • Yeah, about 400 million years ago,

  • our day 21 hours long, not 24.

  • Because of the tide.

  • I'm okay with it, because I feel like

  • I'd struggle to fit everything into a 21 hour day.

  • Yeah, so you're thinking that millions of years

  • when it's a 30 hour day,

  • - people are gonna be like... - ( laughs )

  • ( sputters ) ...a long day.

  • Yeah, the days got longer and then people started having longer meetings.

  • - ( laughs ) - That's what happened.

  • Yeah.

  • So when we filmed the footage in the wave pool,

  • it looked a bit like a sound wave in 3D space.

  • And you've done experiments before with vibrations and frequency

  • to try and show what's happening with the tides

  • and you've asked us to get this stuff here.

  • Yes, this is the Chladni experiment

  • and uh, that little device over there

  • is a sign wave signal generator.

  • And it's gonna function like the sun and the moon.

  • The vibrations from the sun and the moon.

  • And this area here, this is the ocean.

  • and we're gonna put some salt on that

  • and it's gonna demonstrate how the salt

  • will dance around or resonate with

  • the various signals from the sun and the moon.

  • When scientist look at tides,

  • it's really all about the oceans responding

  • to the vibrations, or pulses, or beats

  • from the sun and the moon.

  • So what I've got here is a way to look at that.

  • So go ahead and pour the salt on there...

  • - Okay. - ...and as you turn the signal generator on,

  • You wanna do it?

  • Well, you're the sun and the moon.

  • - That's fair. - Yeah.

  • Jonathan: So as you turn the signal generator on

  • you'll start to see patterns form here.

  • Gav: Why don't we start with 60?

  • Oh, I see a bit moving around the edges.

  • Dan: Gibberin'.

  • - It's gibbering - I like that.

  • Whoa.

  • - Jonathan: Oh, wow, it's bouncing. - Dan: Oh, wow. That's cool.

  • Gav: An "X." Get more salt on there.

  • Sure, let's get that on there.

  • None of that salt wants to be in the middle,

  • that's interesting.

  • - Dan: Oh, that's really weird. - ( Gav laughs )

  • Dan: It looks like static from a TV.

  • Oh, it's spreading. Circle's getting bigger.

  • Do it again.

  • - Oh. - Gav: Yeah.

  • This made two lines perfectly.

  • And that's not a huge jump,

  • and now that's two completely parallel lines.

  • As the frequency alters, so does the pattern.

  • Which is an indication of how the patterns

  • and the tide change with frequencies

  • from the sun and the moon.

  • 78, here we go.

  • - ( grunts ) - Steady on.

  • Oh.

  • I need to put more on, eh?

  • - Oh, it's making like a-- - Gav: Like a plus sign.

  • All right, go then.

  • I'm gonna run out of salt here.

  • Oh, quick.

  • - Oh, it's making a circle. - It's a circle.

  • Dan: A bit of acorn that one.

  • Do you like the little tappy technique?

  • - Gav: Yeah. - Dan: That is so weird looking,

  • the middle part.

  • So this shows how the ocean tide is basically

  • a response to the vibrations of the sun and the moon.

  • A patterned response.

  • You know, it might be worth whipping out the Phantom

  • for some of this.

  • - It's what we do after all. - Yeah.

  • Okay, the Phantom's set up 1,000 frames a second in 4K.

  • Dan, what would be your preference for frequency?

  • Well, I-- I think we started at 60 and went to 67

  • and there was a lot of activity and jumping around.

  • Yeah, there was a lot in the middle,

  • so I think we can contain it.

  • And also the sides were pretty cool as well

  • 'cause it just went crazy on the sides and everything that--

  • Yeah. Well, as you can see we've got the whole thing in the shot,

  • so whenever you're ready.

  • Okay, I'm gonna whip it on

  • and crank it up.

  • - Are we ready? - Yeah.

  • - So this is sixty. - Yeah.

  • And then it goes 67.

  • There you go.

  • Whoa.

  • Why don't we walk