i have a. song to sing along to you she has to come from soup. for . interactive exercises. everything is online mel file an interactive benjamin $5050.00 w. . welcome tomorrow today the science show on d w coming up are micro plastics harmful to our health scientists are studying fish to find out more. clicks shares and likes what makes social media so addictive. doctors with headsets how augmented reality is changing medicine.

we play with it. even certain honest it's hard to imagine modern life without plastic almost 350000000 tons were produced worldwide in 20. but plastic pollution is a serious environmental problem as the life cycle of an ordinary water bottle shows . plastic bottles are made from petroleum the light particle can be found pretty much everywhere. globally every single minute of the day a 1000000 are sold. placed end to end the plastic bottle sold in 2016 would form a chain stretching all the way to the planet mercury. so you've bought a drink in a plastic bottle and finished it what happens next. in an ideal scenario it will be

reuse some can be refilled up to 15 times if they're washed properly most are not sturdy go. many end up in a shredder where they're ground up into flakes of plastic. these can be used to make products like fleece clothing very nice except for the fact that every time the fleece is washed it releases plastic particles into the water. asked for the rest of the plastic bottles they get thrown away dropped right in the street or somewhere out in nature a large number of them land in dumps or are eventually carried out to sea. between 5 and 13000000 tons of plastic garbage end up in the ocean every year a huge problem because plastics can take up to 450 years to decompose. if plastic trash doesn't get caught in propellers on ships or isn't washed up on a beach then the floating pieces grow smaller and smaller as they drift with the

currents. algae grows on their services and that smile draws fish and sea birds they think the particles off food and swallow them when too much of it collects in their stomachs real food no longer passes through and they starve. and if those fish end up in our nets they enter our food supply directly to the rest canned or fresh seafood. is that really something we want to eat. it doesn't sound tasty from sea salt to beer tiny bits of plastic have been detected in. so far though surprisingly little is known about the impact of micro plastics on our health researchers are taking a closer look. how dangerous are micro plastics to human health. professor thomas brownback is researching the. acts of micro plastics on different fish can the particles permeate the

intestinal wall of the zebra fish and reach our organs their digestive system is very similar to ours. we're just as interested in how fish are affected by micro plastic particles in the outside world in rivers lakes and other bodies of water. in the back of our minds there's always the hope of learning something about the potential effects on humans. but on back adds a fluorescent substance to the micro plastic then he feeds it to small cross stations that fish feed on micro plastics research is still in its infancy and the vast array of variables is a headache the variables such as the multitude of different types of plastic with plastic. like this has different properties to a micro al plate like this. which is very firm but also totally clear totally transparent. so we can expect their plastic particles to cause different effects.

if they. would have been that means generalisations about micro plastics are commonplace when the issue 1st arose are not really legitimate. tough. there's a range of factors to take into account when analyzing particles their size alone varies enormously any plastic particle up to 5 millimeters in diameter is defined as a micro plastic in this case there are around 10 micro meters the surfaces of particles also very elaborate particles have smooth surfaces whereas those exposed to the elements outside are rougher but collecting particles in nature would be too time consuming and expensive. it's possible but only in really small amounts which was barely big enough for experimental purposes it might be enough for an in vitro experiment with a cell culture where you only need small amounts. standard exposure of fish lobby

you need a lot more material. over a to begin university professor peter is similarly wary of sweeping generalisations about micro plastics she is trying to find out how polystyrene particles affect trout grow on the larvae of non biting mages she works with 1000000 particles police are of water as a standard what's new is reducing the concentration to levels found in nature to only 10 particles politer that's why previous research results shouldn't be extrapolated into general conclusions says professor. the problem is that when we get an effect with a 1000000 particles a liter we shouldn't start screaming that it's bad for the environment or for trout it's not environmentally relevant. because water air and soil are already full of natural particles does comparative experiments using clay problems may be caused

more by the number of particles than the substance itself a possibility that was previously neglected this is vents if you get caught in a sandstorm also affected by tiny particles. and then they get into your lungs it doesn't have to be micro plastic it could be send. us i think that will be a key issue and one where results can be relative especially with regard to high concentrations. back in pound black cloud the fluorescent agent makes the micro plastics visible in the cross stations which are now fed to the fish despite many trials with a number of variables no micro plastic particles passed through the intestinal walls of a fish experiment fails to provide evidence that micro plastics are absorbed by fish or humans. popular really bright spots on the micro particles straight out the back end of life the fish inside 5 hours. so was it all

a false alarm well partly so far tests of only covered relatively large particles. still can't say it's safe in particular because it's also possible that nano particles form not and they would probably be absorbed by tissues and we don't know what would happen after that. so one widespread suspicion is that micro plastics help to spread pollutants this experiment shows fish larvae in water that also contains a nerve toxin and micro plastics will the micro plastics transport the toxin into the larvae the larvae begin to twitch a typical reaction to a nerve talks in. the entire body contracts because of the toxin absorbed by the micro particles. the toxins also get into the fish without the micro particles except it takes a bit longer. so outside in nature it's rather unlikely that

micro plastics are significant additional factor in pollution. is that so the last one i thought i see no grounds for general alarm. professor tweets going also says people shouldn't panic she found no evidence of micro plastic damage in either her trout eggs or the non biting midge larvae there are however initial indications of a health related impact with her german brown trout the freshly hatched fish whose eggs were exposed to micro plastic are quicker to stretch out into a swimming position although only in particle concentrations $100000.00 times higher than they occur in nature. there's still no evidence that micro plastics in the environment have any harmful effect on humans. based on current knowledge i think we can relax a little but not get too comfortable. we need to focus on issues that are

environmentally relevant as. the sheer diversity of micro plastics means we're currently in no position to make generalisations but researchers do say they know one thing that whatever the case the vast amounts of plastic waste circulating in the environment have to be reduced. classes are more environmentally friendly alternative to plastic packaging but it also has drawbacks it's heavier and it's more fragile. i'm a programmer from morocco has a question about the. why does glass shatter. let's 1st take a look at how this transparent material is made. the usual ingredients for

commercial glass or sounds of soda ashley lime and often recycled glass it's all crushed together and melted but well over a 1000 degrees celcius. when the molten most cools it undergoes a transformation into a tough but amorphous solid meaning it can be shaped into everything from bottles and drinking glasses to window panes. while other solids like metals may be pliable and flexible glass is hardened brittle. when it's put under too much pressure it doesn't deform it breaks. and for that reason it really survives a fall. it's. a big temperature difference. between say ice cold water and a hot glass bottle while filling a cold glass with boiling water is likewise not a great idea. unlike

metals glass is a poor conductor of heat. so if you pour cold water into a hot glass the inside surface of the glass contracts. but the outside remains warmer creating a strain inside the material small fractures for months spread causing the glass to break. glass can also be shattered by sound when of the right frequency the sound has to be very loud and sustained over these to work. when it is the glass begins to oscillate rather like this bridge and that can result in what's called a resonance disaster amplifying the oscillation and causing the glass to break.

the glass will also break more easily if it has a flaw such as a tiny fracture or material weakness. and if that doesn't work. there's always this option. if outlet is red white i mean what are you. going to. do you have a science question send it to us there's a beauty o. text or voice mail if we answer it on the show we'll send you a little surprise as a thank you just as. you'll find us online and on twitter and facebook and we had a question for you too on facebook we asked. how much. time do you spend on your smartphone and what do you do. i don't even know what it feels like without a smartphone mr google always answers all my questions. so i think i want to

run also brings plenty of time online about 6 hours a day she reads messages and posts on what's been facebook looks things up on google or watches videos on you to. you so food is also a fact he's on facebook a lot usually until midnight. but what's behind our craving for social media. catalina and philip a typical of the social media generation she has an instagram account devoted to lifestyle topics here and he posts now and then and shows how much time they spend a day unless mark phones i mean 3 hours. for me you know with me it's between 4 and 6 hours missions and i'm trying to cut down a bit even if i just want to check something quickly i end up spending half an hour

on instagram or wherever i am. montauk is one of a handful of researches in germany systematically researching the impact of online media he believes we need to improve our grasp of social media and use it constructively rather than being enslaved by it social media companies use sophisticated methods till you are in users and keep them. here are 3 examples 1st the like button facebook invented the thumbs up idea 10 years ago now all social media platforms have that inversion. such as the instagram haunt. as far as an ashtray. every single like my posts get because i put a lot of work into them like so basically instagram is currency on instagram. gusts the next it's essential a social reward that's relatively clear that this simple thumbs up leads to

increased activity in the brain's reward system. the students. something researches can see and scans a high number of likes activates the same parts of the brain is eating cake or taking drugs as it happens facebook and co have plenty of insights of their own into our brains as evidenced by a leaked internal document facebook's algorithms can analyze our online activity to determine when we feel worthless insecure and anxious and that allows advertisers to pinpoint when we need a confidence boost and then gordon think hey i'll treat myself woman commitments are hard what that means is that emotional stimulation can often lead to irrational behavior and i might be more inclined to do some impulse buying. and social media companies they keen to spark an emotional response in music and

they can test how to do so for free for example number 2 by experimenting with fuses. and 2012 facebook conducted an experiment with 600000 users without their knowledge group they found primarily positive emotional content in the news feeds and group being primarily negative emotional content users in group a went on to themselves post more positive content while group b. wrote negative posts if there was no emotional content in their feed at all uses simply locked on less. field on top of a companies have a vested interest in finessing their platforms so they conduct similar tests with thousands of users. you have no idea that part of an experiment this isn't the ultimate goal is to keep users logged on for as long as possible to not move. evidently working in the case of philip. when i've been staring at my screen for

ages i'm always really hurt i know i've been on the phone too long but i see the time and say it's one of the morning time to call it a day with a view for. that example number 3 to refresh a function that keeps. us crean's. in our day to day lives the activities we engage in normally have a beginning and an end for when we finish them we can cross them off our list and move on to the next thing. just a start that doesn't happen with these tech platforms and if they're on you tube prigs sample once one video ends another one starts like this next so when we're using these platforms we can feel reticular just keep scrolling endlessly. and the more we do so the more data the companies collect on us which they can then parlay into advertising revenue if it does miss posts here to prevent that from happening

and it can happen very easily i set myself a deadline that after 10 o'clock at night i put my cell phone away and either read a book or got a bad name when i'm 5 and you know. if we go out for dinner then we both try not to get our phones out but then you also. so there's at least one hour of the day when we can have an actual conversation to come and also take the opportunity to just switch health. but don't switch off just yet another kind of digital technology is taking off augmented reality is making inroads in all sorts of places. in museums architecture and many different industries. technology overlays digital information onto the real world it's already expanding that arises of medical education and

surgery. deep in the basement of the munich university hospital the team here is working on the future of surgery but they aren't doctors this simulated surgery is being carried out by computer science students the technology they're developing could revolutionize surgery. that they're using augmented reality glasses its software recognizes the surgical instruments and provides instructions. play video. voice command. scalloped information displayed in their headset such as step by step instructions on how to set up an use the various surgical instruments. and live in. fact free and. play video. users can ask for more explanatory videos graphics and photos. the system means everyone knows

precisely what they have to do where and when. surgical assistance to not only to. assist during other kinds of operations can now also help special operations into systems. and high tech operating theatres it's not uncommon for the surgical instruments they are all that familiar with using augmented reality glasses that means they don't have to spend hours reading instruction manuals. you know. we request that the instruction manuals for surgical instruments be available in the operating theatre instrument then we check there and then how the instruments are put together. that is not an unrealistic scenario it happens very often so i can imagine that this new system would make the job significantly easier business and. the team

of computer scientists at munich's technical university are world leaders in the field of augmented reality applications in medicine and surgical instructions are just the beginning one day doctors might be shown a are images overlaying their patients would allow them to see inside the body the organs vessels nerves and tumors. the doctor can directly feel in a patient. there is a narrowing of artery there is more it can be that if location is the body so we look realising intelligently correctly in visualizing it correctly in our demented reality we're hoping that we would improve the health care. to make that possible the software we need to integrate. data from regular x. rays cat scans or m.r.i. scans to generate a precise 3 d.

image super imposed inside the patient's body. the doctor would see a 3 d. image of the bones inside the leg and use that information to for example attach an artificial knee with much greater precision. and with the previews of investment that they're making in this direction i think very soon we have to be used on an everyday basis. such complex technical developments in the field of medicine have to be thoroughly tested before they can be used on patients so it will likely be a few more years before augmented reality is deployed any replacement surgery but it's already being used to train medical students. at munich university hospital they're already using software developed by the team led by nasir knob. it's called the magic mirror and is used in the teaching of anatomy it can generate 3 d. images they can also generate 2 d.

cross sections of the body instead of learning anatomy by dissecting it could have or they can study it using augmented reality. we can't do this with a human body we can't cut one into slices with this technology we can examine the topography of each organ and where exactly it is. and the advantage of integrating magic mirror into this course is that the students can investigate their own bodies and find out exactly what each blood vessel is. this kind of work with augmented reality also helps prepare medical students in munich for the clinical practice of the future. to realise. to work with patients when we come up. real solutions using code mounted display program to do your duty for the approaching room they

would be ready to to use it because they are complicated from the for. the medical students also get to work with the augmented reality surgical glasses it's display replaces the magic mirror each student can study the inner structures of the body even when they're working in large groups. in the new. couple there are often 10 or 12 of us gathered around a real corpse in anatomy class. but with small glasses we can all see each muscle full scale courses on it all. augmented reality is set to transform medicine. anatomical models that get up and walk away are just the beginning. that said for today's show next time we go to the seaside to the never ending sound of waves lapping the shore so why doesn't the sound feel like knowing. many of us

find it relaxing in fact but how do weights make sound join us for that on the next edition of tomorrow today see that.

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this is g.w. news coming to you live from berlin u.s. president trump threatens iran's cultural sites and warns of sanctions on iraq as blowback over the killing of tehran's top commander grows iran's leaders have presided over a funeral service for general customs holding money hundreds of thousands of iranians have taken to the streets to mourn his death bed room.