news or visit our website dot com. well come see tomorrow today the science show on t w. this time we go to the beach where surfing physics teacher explains what waves are all about. we'll hear from an acoustic sexperts why the sound of waves is so relaxing. the waves can also have huge destructive power and scientists are trying to predict rope waves. the oceans are in constant motion waves packing at the surface of the water but ways are not equally high all over at the equator they tend to be more shallow at higher latitudes they're stronger. a wave can traverse entire oceans but it's not actually

the water itself that is moving with the wave confusing let's head to the shore and find out about waves and where they come from. the atlantic coast of portugal and spain for its waves large and small purser 1st of all novels of ability and as an enthusiastic wave rider he's also a physics teacher so he knows something about how waves form and what surfers find really epic a perfectly shaped long way surfing requires practice and patience to document it's often just luck you have to be in the right place at the right time there are so many factors the height of the tide the when the wave period that play a role and sometimes there's just a tiny window maybe half an hour a day when you get good way and the rest is rubbish you know if. this works. like

a good moment. the surfing science teacher seizes the opportunity. but what bar and waits exactly. waves are the transfer of energy. transfer and energy. so far today's waves have been pretty tame let's do an experiment on the beach and yes take a shake says tom we can see how the wave is being propagated through the length of the cloth because shaking is providing the energy that's being transferred. but what does a wave in a towel have in common with a wave in the ocean. more than you might think. whether it's a towel wave or a water wave bit of the waves transport energy not matter. even though that might not be obvious that seen from the beach the water is just the transport medium.

just like the surfers waiting on their boards the molecules in the water don't move over great distances the waves propagates much faster where all that is the energy in waves come from it. it depends on what kind of believes we're talking about. the moon this gravitational force keeps the ocean in motion. its attraction produces the rising and falling sea levels known as and flow. but the waves that interest surface are generated by the wind what matters is how strongly and how long it loads it gets the water particles moving. here's a simulation the hairdryer makes a wind which makes waves. planes

can travel for days and hundreds of kilometers from their place of origin in the middle of the ocean to the coast. long and shallow waves tend to travel faster than the short hyla ones which slow themselves down. within the waves the water particles follow circular or orbital paths. that this orbital movement extends deep down in the water the deeper the water the smaller the radius of the circular motion but when to circle in the water particles hit the seabed they're stopped and then. that makes shallower water waves. breakers are typical shallow water waves. they occur when the water particles below the surface are slowed at the bottom of the

particles above continue to move on their circular patterns unhindered. be unchecked water particles move upward making the wave tower up at the shore and then break. to the delight of the surfers. ya block up to it makes you happy it's very exhausting by night time you're totally knocked out but happy you forget all the everyday stress it's just great. but the best brains don't come on demand which is why this evening until yes he got is still in the water waiting for that perfect wave. but waves can also be scary in the person sail is reported towering way. that suddenly

a rose out of nowhere on the open ocean but scientists dismiss these accounts until the mid 990 s. that is when a so-called rope plate was documented on an oil rig in the north sea. this freak plate measure 25 metres in height. now researchers are trying to understand and recreate these monsters. in the ocean waves that are between 8 and 10 meters high are commonplace but at any given time anywhere in the wild there are likely to be 10 also rogue waves up to 30 metres in height. they appear suddenly and without warning. scientists recreate rogue waves here in the wave basin of the new push concious institute in hanover here the water isn't whipped up by storms or currents the

waves of generated by these panels which are controlled by a computer. they enable the scientists to simulate nearly every kind of wave at a scale of $1.00 to $75.00 everything from small harmless ocean swells to gigantic monster waves all the way for me to shows the current height of a wave. music outcome is going to simulate the drop no way the 1st rogue wave ever documented it was measured on always drop an oil rig in 1905 and i didn't know what we can see it clearly in this north sea story it shows 8 to 10 meter high waves on average during the storm then here we see an extreme of that a wave that's 25 meters high a rogue wave months of. what's unique about rogue waves is that that $2.00 to $3.00 times higher than the highest waves around them. that also makes them $2.00 to $3.00 times a steep. hill. roque wave has almost 10 times as much force

as a normal way of. usa for a long time it was a mystery how a wave more than 20 meters high could suddenly arise in a storm of 8 metre high waves but only to fan ishaqi thereafter. the explanation waves don't spread out equally in the water waves with shorter wavelengths in which the troughs and crests quickly follow each other only move relatively slowly. waves with long wave lengths are faster. they can catch up with shorter ones. when that happens they can combine to create a highway. of several waves joined together in this way they can become a rogue wave. rogue waves are extremely steep the ship has no chance of sailing over the crest of

a rogue wave as it can with an ordinary one instead the water crashes over it. as. the water masses collide with the structures on deck with tremendous force in a real scenario at sea this would break the ship's windows and bend heavy steel elements. that scientists can simulate monster waves in on the bar tree but what they really want to know is under what conditions and how often such waves will occur in nature. what is the likelihood of a freak wave forming. previous estimates had suggested that the probability of finding a way of higher than 10 meters in a heavy storm would only be 0.03 percent. but measurements show that giant waves of come. much more frequently the actual chance

of wade's forming that are at least 10 meters high is closer to one percent it's last a shut in that's the classical approach it hears to the theories that every wave has a certain energy so that the energy of one wave can sometimes overly that of another to form a particularly high wave and that the component waves each with their own energy can there after continue on their way for form all new or approaches theorize that energy can also be transferred from one wave to another and that there's 2nd wave moves are on would somewhat more energy and the 1st one with a somewhat less it was the in you can if you out so the waves would take on energy from their neighbors and grow at their expense into a rogue waves but can him danger even big ships at sea

this is not a rogue wave but it's a nami tsunamis are not generated by wind at the surface but on the seabed usually by earthquakes when tectonic plates colline releasing massive amounts of energy and displacing huge volumes of wasser bar at it seat synonymy says still relatively small waves traveling fast but point may reach the shore they slow and the water piles up into towering waves dozens of meet his highly which can destroy everything in their path weights ont only powerful they're also pretty low out they can get up to 100 decibels that's as noisy as a jack can it 10 meters away sound is generated when the

waves break but despite the volume the sound of waves is generally perceived as relaxing. that. waves break on the shore it day and night and have been doing so for millions of years. nobody seems to mind the noise in fact most really enjoy the sound why is that. if anyone knows the answer then scientists at the frown hole for institute for building physics based in stuttgart germany. this is our echo chamber will use it to test absorbers. peter punched ed and his colleagues research how people experience the sounds that surround them the field is called psychoacoustics they also develop products. here they're working on

a booth with sound absorbing properties where one can conduct private conversations without being overheard. this chamber is anechoic that is totally soundproof it's used to test things but it's not actually pleasant to spend time man. this is to lecture it's perhaps rather too quiet we're not built to hear nothing at all it's we can't close our ears in contrast to our eyes all our ears are our original vigilance systems warning us of danger as seen our hearing is always switched on is designed to receive signals and issue warnings to protect us from harm. for good falzon to violently supervolcano. this kind of sound is better than silence if we want to relax. i just like. that it has to do with the structure of waves. it's not

a uniform constant noise with the same volume but rather it rises and recedes regularly it's. like the surging is a very relaxing kind of sound for us very familiar and with positive associations. for. prostitution us it's. white pink and brown noise are characterized by equal intensity at different frequencies the sound of waves exemplifies that when you give voice to. the sounds of produced as water slaps on the water and displaces ad when without movement there would be no noise and or kind toward. people like certain kinds of sound with or without ocean waves technically generated white noise is sometimes even deployed in workplaces it can disguise other sounds.

and it can be soothing. alshon and seek take on you this kind of noise doesn't carry information so after a while our brains infer that they don't need to do anything until in the noise out all register it subliminally. when feud even so that's why it feels relaxing. by listening it's not real silence there is something there but it's not threatening is take it's not telling us anything so we can just relax your attitude as you in synch but to. weights might still primal anxiety and let us sleep easy but one of the ocean is far away. is highway noise and effective substitute. is one for when traffic noise isn't all that different when the vehicles are just passing by at

a constant speed and not starting and stopping on the stuff once again the sound is continuous over time and have a constant volume because the cars are driving at around the same speed in the fog so i get on with a farm the think is when the cards here are. so in a sense listening to a highway should be a good lot of ice except our brains link the sounds to the cause of them and the associations are anything but mellow traffic speed concentration stress i. designed of waves by contrast feels friendly reminds us of the cation or allows our minds to simply go blank. we asked on facebook what do you think of when you hear the sound of waves. myra from venezuela loves the sound of waves and says nothing is more relaxing them

the sea and its waves. every writes from indonesia that the sea is amazing almost along. life it's always rippling sometimes slowly sometimes strongly and sometimes it's terrifying. for pius the sound of waves is very familiar he wrote to us in q so i believe that he's a skilled swimmer and that's what he knows. as the water from indonesia is more interested in the ocean waves as a source of energy and says we might be able to use them to replace fossil fuels and that's true. there have been many attempts to use the forces in the ocean waves to generate electricity we've been successful with other forces of nature solar power for example is most advanced in china india and japan according to the international renewable energy agency. other countries are focusing on

wind energy here to china is in 1st place but it's proven very difficult to harness the energy of waves. immensely powerful forces. huge wind generated waves. of the tides controlled by the moon's gravity. with an area of 360000000 square kilometers about 70 percent of the earth's surface is covered by water. most of it is in the ocean which could be a matter of force of climate friendly energy but how can we harness that power tidal amplitudes very dramatically around the globe in parts of western europe they're particularly pronounced. the 1st tide mills were built in the middle ages or even earlier they were driven by the daily changes in water levels. in

the 1960 s. this idea was picked up again and engineers built the 1st big title power. station in britain the in france. turbines inside the tidal barrage are driven by the admin flow of the ocean. but the engineers encountered a problem only few days are suitable for this type of power plant and the garage has also disrupt the coastal ecosystem. but that didn't stop them they saw other ways of using marine energy this time focusing on the strength of waves. wind generation surface waves tend to be large and strong as high latitudes of the northern and southern hemispheres. in scotland in the 1970 s. scientists developed a series of new mechanisms intended to convert the energy of surface waves into electricity many believe that way the energy conversion is we're on the verge of

a breakthrough. one such device that's called the salters dark named after its inventor stephen salter from edinburgh the duck was tested wave time but never on the open sea. eventually these ideas fell by the way start. in the early 2000 came a new attempt with this snake like old shore device it's linked cylindrical sections flex and bend in the waves and convert the motion into electricity but it never got past the prototype stage. german engineers are currently testing another system the knee most project involves flotation modules connected to pulleys on the seabed by flexible cables as they're pulled by the motion of the waves a generator transforms the mechanical energy into electricity it's being tested as an addition to offshore wind farms. so far most of the approaches to

topping marine power have got nowhere one reason the formidable technical her. wave heights change continually counters the force of the waves to stand up to the biggest waves the machinery has to be very robust but this equipment produces too little energy when waves are gentler there are many different ways of harnessing wave power but they're all still too expensive to be viable. tidal energy developers shifted to anchoring the turbines on the sea floor by other than in barrages but underwater repairs are expensive. plus i plot forms have turbines mounted underneath that are more accessible and thus easier to fix when the corrosive salt water damages the machines. although the energy of the wild and salty seas has repeatedly proved difficult to

harness many engineers remain optimistic that a breakthrough is just around the corner. if help what is right why upgrade even if you. know it's time for all of you a question this week it comes from morocco i know you took a look at the ways in the ocean and asked where the water is really transparent. the water in this class looks transparent. the ocean looks blue book at both water so why the difference. to understand that we need to delve into physics carbon is an effect of light and without light everything turns black. the light from the sun made the white but it's actually a mixture of a range of wavelengths some of them are invisible to the human eye like ultraviolet

rays parts of the spectrum all visible to us that we see them as red. yellow green blue violet. and when they're mixed together we perceive the light as white. so why do different things have different colors. because they absorb different parts of the light spectrum the rest is reflected and picked up by the receptors in the eye. the material the jacket is made of absorbs blue green and yellow light red like to be reflected so the jacket looks red. so what's going on with water. close to the shore where the water is shallow the light mostly passes through without being absorbed or reflected.

but when light rays form on a larger body of water the red orange yellow components of the light are absorbed more strongly and the new light is preferentially reflected. so that's why the ocean looks blue it's not because it reflects the sky. divers can observe the effect of absorption as they descend into the depths 1st the red light disappears then the green and then the yellow what remains is blue light that hasn't been absorbed by the water further down that too is absorbed and you get to a point where no visible light at all has penetrated. so the color of it was a seems to have depends on the quantity of it large volumes of water no clue. but a small amount of water appears transparent. you know the

science question then just ask you'll find us at v.w. does. com slash science and on twitter and facebook. here's a fun fact waves have a strong effect on animals and plants take the ball on a cold you know there is little alfred pods that appear to stones or shells and the boys said they rely on the waves to bring them a new trance and the waves determine how long their penises are where the waves are strong bond holders have a shorter penis when the flow is gentler it grows longer and in any case male body cools have the longest penis in proportion to their body length of any animal. next week will be heading for bangkok a city that is critically affected by climate change how can residents adapt to the constant flooding more of that on the next edition of tomorrow today see you soon

popeye. enchanting forests that invite visitors to dream. huge mountains to bear witness to try to. read online story line true returns from a. bohemian switzerland by reno. next

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