 I'm going to start with this. I hope you can all hear me. I'll shout a bit and hope that you came. First of all, thank you all for coming this evening. I appreciate it. Otherwise I'd be standing here in an empty room talking to myself, which I suppose is an occupational habit of physicists as well, and that wouldn't be if I didn't think quite as much fun. So, what I want to do today is to share with you some things which I've been given the title of the wonders of physics. Physics, of course, is everywhere, as Elizabeth was just saying. Everything we do, everything we touch in the modern world, has something connected with physics, and physics is in the news. I'm not sure if we necessarily all understood it, but physics was in the news as of yesterday when it was announced that the primordial gravity waves of the moon have detected, and that seems to put us all the way back in contact with the big bang, the first factions for the second of the existence of the universe. So that's the kind of subject that physicists can be involved in, as well as perhaps more everyday things. I thought to start, I hope you all know what wonders are. I hope by the end of the evening that I'll have some ideas from other wonders of physics, but I thought we might think about, first of all, what is physics? It's a subject which tends to get kind of gas or, I don't know what it is, the agorational fear if people say that you're involved in any way with physics. I don't quite know why it is. It doesn't help, I suppose, that the dictionary definition is this kind of dry one, which is the study of the matter, energy and the interaction between them. All right, but what it really means is asking questions about anything in the universe and trying to answer them. Trying to answer them by carrying out sensible and well constructed experiments and thinking about what the answers you get from those experiments are. Then asking some more questions. It ends up that you are simply a curious person. You just want to know how things work, why things happen, how things are. And as far as physics is concerned, we go from everywhere. From the origin of the universe to far into outer space to nanotechnology and the really sub-visible microscopic zone. Everywhere is the enrich of physics. Physicists are there asking questions about any of those topics and trying to answer them. I'll start with a quote from Albert Einstein. There are plenty of quotes by Albert Einstein about the variety of topics he clearly thought long and hard about what he was doing. One of his pieces of advice, which is a brilliant one to all of us interested in the way the world is, is to look deep into nature and then you'll understand everything better. So tonight I want to look deep into nature and hope you can have a little bit of better understanding. Now I can't take the whole lot. I suppose as a professor I should be able to talk as long as it took from the origin of the universe until now. I'm supposed to like the sound of my own voice but I'm not intending to do that. And I'm not going to cover every conceivable topic and every conceivable scale. What I thought I might do is think a bit about what some of the things that physicists do are and then have a quick selection and look at three topics, three areas in reasonable detail. I've found a few things and this is by no means an exhaustive list. They produce energy. They treat cancer. In fact they partly diagnose cancer as well as treat it. They develop new electronic devices in all due to the mobile phone, which is a phenomenal piece of technology and we take it for granted. We look at mobile phones. We make new materials. We understand the climate. We don't understand the weather because it's something different. We certainly don't understand something about the climate. We study space, the solar system and beyond, and we investigate fundamental particles. Probably the most recent news story before the one on primordial gravity waves was the discovery of the exposure. Again most people kind of explain it on the news. It didn't get anywhere but there is a particle there to the planet to be discovered experimentally. So physicists are interested in the fundamental particles, the building blocks of all the matter that we encounter all around us. So I'm going to choose, for my wonders of physics, something from everyday life. I thought I'm going to have a great time when I put this together. What sort of things can I think about, about the physics of everyday life? Of course the first thing I start to think about is anything that's got high technology. We immediately think that physics goes there. I'm going to talk about, first of all, climate. Now, climate, we're all aware of that. It's a recent mild night tonight. Most people are right with coaxed but not max and umbrellas. We're all interested in this topic and it is an example of a realm in which physics has an awful lot to tell us. I can't resist mobile phones so I won't. I should put something about mobile phones. Finally, because it's my area of research, I want to say something about materials. We're not going to be talking about materials I personally worked on, but we'll have a look at some aspects of materials and what we know about them and what we can understand about them. So now let's turn to climate. Now climate is another piece of physics that was in the news that most people would recognise as physics. Here's a sort of climate that we saw not very long ago in the recent winter. Here's something driving along in quite a stormy day. Here's an even more spectacular one from the coastal region of Devon. We were struck by a series of really heavy storms this winter and that's the kind of thing that climate scientists are interested in. Not just tracking the weather in some just recalling events way, but understanding trying to predict what might be happening. And so climate physics has emerged as a discrete but important subject and it's the application of physics in the study of the climate. Now I've talked about climate so I ought to say for us what's the difference between climate and weather. I've got a couple of quotes here and really if you like weather you can put your nose out the door. Is it raining tonight? No, that's the weather. Climate is what's the average temperature in the last 12 months or the last five years or something like that. So the weather is if you like the local immediate manifestation of climate and the climate is the average of the weather over the longer time. And physicists are really interested not so much in predicting the weather though the people who work in the meteorological office are largely physicists and meteorology is a branch of physics but the people who are interested in the longer term duration of understanding the weather and predicting it would be more considered climate scientists. So climate. Now how does climate physics go together? Well there are several features of climate that are clearly physical. They all are really, but there are several features that are obvious. One is temperature. And it's worth saying that the temperature of our earth is controlled mainly by the output radiation from the sun. Now you could be forgiven for perhaps overlooking that fact. It's very obvious that you could be forgiven because it's normal to talk about greenhouse gases and greenhouse effect and the effect of carbon dioxide and we forget that in fact what we're doing is influencing how the earth interacts with the sun. So that is the temperature. Now it's not only controlled by the output from the sun it's also controlled by how much energy we on the earth, the earth itself, throws back out into space. So the temperature is controlled by the sun. And measuring temperature is a big topic in physics not just how do you measure temperature but it's easy to measure if you're going to take temperature now in this room but how are we going to take the average temperature of the earth? How are we going to take temperature over the Antarctic and over Central Asia? We've got some interesting problems of physics associated with trying to understand something that seems as straightforward as the measurement of temperature of earth. Then there's precipitation. Well it isn't a night which is great but it often does rain or snow. And this is controlled by the state of water in the atmosphere it's controlled by the state of water in the clouds the whole interaction of the clouds with the radiation hitting the earth is a major research theme in the time of physics we don't know it, we may sit and look at the clouds and think it's all very obvious we know what's going on but there's such a lot still to find out. And we only get precipitation if the clouds move from a warmer region to a cooler region and when they get cold enough they will actually deposit their precipitation so you need some sort of movement which brings us onto the third part of the climate that I want to mention which are the winds. The winds are driven by two things convection currents in the atmosphere bits of the atmosphere warm up I'll show you some diagrams in a moment but bits of the atmosphere warm up as they rise they suck cold air in under me and that's one of the drivers of the winds not the only one because the other thing is the earth is rotating and that starts to swirl the atmosphere around and that makes a difference as we can see so we'll have another of these these two drivers of winds the convection currents and the earth's rotation first of all here's a nice rather pretty picture of what happens with convection and you've got what looks like a nice summer's day here and you've got in the middle of the picture in red some warm air the sun is up in the sky and it's shining on that faction road and the air there is warming up and warm air is less dense and will rise and when it does that doesn't mean a vacuum behind it draws cold air or cooler air in from around it now on that sort of sunny day that sort of scenario we're not going to see much in the way of wind but if we have enough heating we will see quite severe winds following into the cold air beneath so that's one of the major ways in which air movement and winds are driven the other is the earth's rotation and this is a really busy diagram but what I really want to show you is let's see up here first of all the earth is rotating and what we've got as a result of that are some prevailing wind tendencies and we've got nearly quite a lot of the wind tends to be drawn in this direction which is sort of right to left because it's predominantly warmer air is causing the wind if we go further north and the air is getting colder it's coming down towards the earth and it tends to be going in the opposite direction but you have just as a result of the rotation of the earth distinct patterns of wind as you go from the north pole through the tropical regions back to the south pole and although we've got these rather complicated verses this is a sort of diagram of what's happening in an individual convection current effectively so we have these convection currents around in these zones as the air is doing what we say we can do rising where it gets hot and cooling down and coming down again and circulating like that but the net effect is of the zones of well defined wind now why do we have such bad winds in the winter well it's not entirely clear but it's to do with the changes in the atmosphere around about this zone here and where it was relative to Britain what the effect was devastating I think to understand unprecedented high winds around our coast and so winds are an important part of the everyday world of physics and the weather there's some other things that make a difference to our weather one is the extent of the ice mass the ice is interesting stuff because it's very difficult to heat up and to melt it takes a lot of energy and if you have a lot of ice and we can use it without ice in the polar regions then that acts as an energy sink and melting it is really difficult it takes quite a high amount of energy and if you have a high large ice mass it will tend to be reasonably stable do expect this to stay itself in place and that makes a total difference an overall difference in the climate on earth now there's a bit of discussion about what's happening for the ice masses in the poles and it depends on which authority you read at this stage I'm not going to take signs but I certainly am not melting at the rate that it means that all the polar bears are going to float away on little ice flows and die in the sun so that is a bit of an exaggeration but there is the decisive discussion and in the end it's going to come down to something I'll go back to which is measuring how do we know whether there are changes and how reliable are the sort of pictures that we're looking at ok so that's one thing the extent of the ice mass is another factor that makes the difference in the climate the second thing on this slide is the earth falls around the sun and it's tilt the earth does not go around the sun in a circle it goes round in anilics which means that some of the year needs to go further away from the sun it's colder but it's nearer the sun it's warm so that's one of the factors that makes the difference another factor is the tilt the earth isn't tilted that right is tilted at an angle and so we have parts of the earth pointed towards the sun at different times and all of these things may be different to the climate just as what it did otherwise it would be stuck in permanent winter or permanent sun the third thing is the concentration of greenhouse gases in the atmosphere I want to talk about that greenhouse effect and greenhouse gases so we'll have a look then at these effects and how they influence climate but as I've already mentioned a really critical part of climate science is the ability to make a measurement and it's quite difficult to do one question is we say well what about just using historical data we know there have been people from way way back 200 years or so even more recording the temperature we know for example that there was a knack in 1707 when it got to be minus 12 centigrade and up and down but somebody was writing all down keeping a diary problem with that is one of the things that affects the temperature is the what we call the state of urbanisation in other words if you start building houses and roads around somewhere it heats up for a lot but enough to make a difference and everywhere has expanded I mean there was a very interesting case about 100 60 years ago one of the early times Victorian times a society formed in London a whole lot of new scientific ideas a society of this particular one was formed and they invited various people who were active to join and somebody wrote back and said I can't join I lived too far away from London and he lived in Islington now we think that's funny because Islington it's all part of London well actually no it wasn't it was green fields it was rural so if you've been taking your temperatures in Islington 14 you would have got a different temperature you've got an average a lower temperature than what you would do if you took the temperatures in Islington now just because we've not roads to Islington we've built houses in Islington and urbanised it so you can't just look at the story of the data and know that it's changed you have to take a bit of a decision about it look at it and interpret what it tells you it doesn't tell you what the necessary thing it is another big question is how do we determine the average and I said to you what's the average temperature on Earth and if you're going and you're looking up you're looking up on the internet the answer is 14 degrees centigrade but how do you know I don't mean how do you know how do you know the internet to rely on what's an average temperature Antarctica can go down to minus 58 Australia on a friend of mine was there five or six years ago and was up to 51 degrees Christmas plus 51 what's the average how do you know and then we take the average of all the places that we've got easy access to we wander in there with our anthropometers pop down the road to at least have a weather station at Q that was an important weather station for a long time so go down to Q and take the measurement there how is that a better average in the middle of the Russian republics or the middle of Antarctica so how do you know the average you have to have a decision you have to decide how to do it but we have to do it by kind of manipulating the figures of things so we have a real problem about the measurement here the last one is unreliability of measurement devices anyone who's ever done any science at all will know about the unreliability of measurement devices they used to be a phrase but then it doesn't work it's physics and anybody who's ever worked in a school lab will say yeah I know why it's broken thermometer it's already a public emergency drain and of course you don't need to measure temperature or something else has gone wrong but it's not only that people send satellites up into orbit and any detective devices have a sort of limited time they drift they don't work as well like a lot of us and they, it's just a little one for my generation in the audience so they don't get the measurements and if you have a satellite the other thing that can happen is it can drift very slightly off course so you're not necessarily measuring parts of the same part of the Earth's surface so you can have unreliability to have some idea where you're measuring devices and perhaps drifting what's happening so it's actually very difficult to start making the measurements the one that's a live topic a live subject you've not solved interactions from important businesses so that's some of the problems now let's go on a bit more and think about our energy where we get it from and why our climate is driven by the sun here we've got this, the sun where we get our energy from it's transmitted across space by radiation radiation that form of energy transmission across a vacuum and we get our energy in the form of electromagnetic radiation from the sun so it's all that grateful because you can see it does here it reflects about 30% of back out into space so it only keeps about 70% and in fact it keeps slightly more than it might if we didn't have the greenhouse gases as we would see so it's reflecting some of that energy back out so we have retained about 70% of the energy from the sun now here's a picture of the sun you can't just go out and look at the sun because it's dark because it's a bad idea to look at the sun and the sun is a very well-studied celestial object and here's the sort of thing that we know about it it's what is described as a medium yellow star and that tells us quite a lot about where it is in evolution of its life time as a celestial body we know about the colours of stars we know about sizes and so on so this is what our sun is we know when it's made off mainly hydrogen and helium it's about three to one there are a few other elements because they're being produced in the core and we know roughly we're going to be able to know very precisely what's happening with the temperature in the middle of the sun is about this 15 times 10 to the sixth really 70° we got this originally in Kelvin but I wasn't going to explain the difference it's so small to get to the temperature so it's extraordinary unimagining the top in the centre in fact it's unimagining the top even when you get to the surroundings and it's relatively stable which is a mercy although it's not completely stable there is good evidence that the output of energy from the sun varies and there is also evidence that you can verify on the sun's terms quite a lot over history so it's output is formed by up to 0.5% we might think it is nothing but it has made a difference on the surface of the sun has been known for a long time are sun sports and when there are a lot of sun sports the sun is varying our energy at its maximum level and as the energy goes down so the sun sport activity goes down there are fewer sun sports now we don't know which cause is which or whether they are both caused by a third unidentified phenomenon but there is this reduction in output from the sun and it's actually implotted people have used various devices historical indirect evidence King were not taking temperatures but they've taken a number of measurements over the years and worked out a sort of cycle of solar events now in fact what they've done here is look at carbon 14 analysis and that has given them information about plant growth and it's given them ideas about whether it is warm or cold so for example over here we have this relatively old period called the medieval maxim and so for a long time maybe even times the sun was relatively warm because the sun was relatively active and we've got used to apparently white warm suns and wild winters but they have been a series of minimum now we know about this one the Morda minimum because by the time of the Morda minimum which ran from approximately 1645 to 1715 there were scientists observing the sun they weren't that foolish but certainly taking images and certainly looking at sunspots so we know for certain that the Morda minimum was associated with periods of low output from the sorry low sunspot activity we also know that it was associated with low outputs from the sun at least indirectly because it was extremely cold so here we are to the local I've been saying the Morda minimum and the Morda minimum was associated with very cold weather and here are some diary entries from a man called John Evelyn who was a famous diarist and he was writing about a particular winter but these winters were fairly typical so first entry that is relevant now on the 2nd of January 1684 he tells us that the tent is frozen that means the river was frozen and what happened now by the 19th I went across the tent on the ice and now become so thick as the bare streets of foods in which they roasted meat people were living but they were going out there they were roasting meat they were having parties on the river because it was so thick with ice and by the 26th of January tent is filled with people in tents and all sorts of layers in the city the city they just built temporary on the frozen river and on the 18th of February 1684 the tent is still frozen and we have number of pictures this is actually a frostfair from about 7 years before Evelyn's diary entry so you can see this is a fairly regular annual event these are the kind of how clear it is people were erecting the booths they were trading from here is a stagecoach on the river and people are able to walk across it now this was strong evidence that it was cold here is a slightly more recent one because there was another little period not such detailed here in the early 1800s but I like this one I wanted to show this one this is a frostfair it falls to feet right there they are definitely on the river walking across it and amazing to me they are roasting oxies on the tent so that ice was pretty thick because I think even whenever we are talking about this is about 1815 if you had a fire to frozen ice it was going to get hot the ice must have been really thick for that not to cause it to fall through we had kicking when we had the water now there is still research going on into this it is still a bit of debate about what this was all about was it that we had debate that partly drives the sun's hot activity partly drives the sun's output and how reliable is the sort of evidence that we've got because we haven't got temperature emissions except for the last periods where we've definitely got these pictures and it's just worth recording that the there's a little bit of a local variation we're not anywhere near a water minimum but we are currently at an 11 year minimum in the sun's hot activity 11 years ago there was something like 155 observable spots on the sun the moment there was something like 68 and there have been like that since about 2009 and the question is is that why recent winters have been caught we might say well they have in North America it was an incredibly cold and Chicago airport they were called the lowest temperature there ever minus 27 degree centigrade so North America was hit by a really cold this winter and our previous winters last two or three years have been cold now I don't know if that's just weather or if it's cold but there is some indication some evidence of coolness and I'm only asking the question meaning as an outsider not a climate physicist but here is climate here is the weather and it's important things so as I said, climate research not just historical it's up-to-date here is the pattern that's being used for remote weather sensing it's worth mentioning that they do not take the temperature directly what they do is measure or radiation that's coming off the earth to measure different wavelengths then they have a problem because you have to sort of put this base together and guess the temperature and not guess, calculate the temperature how do you put the calculation together where there are a number of mathematical models so it turns out that people who are responsible for the satellite measurements and taking them and dealing with them actually use slightly different equations to estimate the temperature so in the end what you find is that people don't try and calculate a meaningful average we might guess an average of 14 degrees but they tend to say let's take something and we'll have an average over the last five or ten years and we'll have a look and see whether the temperature of the moment is different significantly from that average so we tend to look at differences from the kind averages and we tend to know if one person's mathematical equation is a different absolute number it doesn't matter because we're both going to see whether we've got a big spike or whether we've got something a low spell and then I want to go on to the greenhouse effect we've all heard a lot about the greenhouse effect and everybody thinks it's going to be the death of the planet well we ought to be fair and say before we start that the greenhouse effect is actually partly responsible for the life of the planet there are three gases that cause the so-called greenhouse effect carbon dioxide methane and water vapor and again we construct carbon dioxide because it looks like that's the one that we can make this difference to but in fact man-made activity is contributing to methane uptake because of our farming practices increased number of cattle I'm not going to biology of how they generate methane because it's cause the greenhouse effect and they contribute to the greenhouse effect water vapor of course is there anyway and we can't do a lot about that and what is the greenhouse effect and what it is is that energy is absorbed by these gases and then it's re-enitted only instead of it just being being backed out into space it's now re-enitted in all directions including downwards so the Earth's surface gets warmed up and the Earth's lower atmosphere gets warmed up so we end up with a whole system being warmed and then it would otherwise have been without that greenhouse effect and here's a little picture of the greenhouse effect so on the left of the screen you can see the sun beaming its radiation and it's reflecting so one lot I told you we weren't really grateful cos we 23% of it is straight out of the space that's going back out there forget that a bit, you don't want that thank you very much but it starts to be absorbed by our greenhouse gases and then we have some of the energy being re-emitting and going out of the atmosphere but some being re-emitting and coming back down to the Earth's surface so we end up with a generalised warming effect and the whole point about the greenhouse the effect is it's not all bad it's not all bad because without any greenhouse gases the Earth's temperature well we think it's all clean and if it was minus 18 it would be too cold for us to live on Earth or anything to live on Earth so we need the greenhouse effect we may have turned it up a bit too much but we certainly need it and we have to be very careful about it and I said here that the precise effect is still being studied the atmosphere is extremely complicated and I don't say that just because of the sort of omittedly motivated individuals who deny climate change climate change is clearly happening because climate change is all the time so it's really foolish to say it's not happening but we have to be a bit careful with some of the people who don't know what they're thinking about it the reality of the situation now is that this thing is complicated we had computer-predictive models that were saying that the Earth's temperature was rising in line with the increase in carbon dioxide levels but that increase has leveled out we had people looking at the model and predicting the great authority on the basis of the model and the data they then had in the year 2000 that by 2010 there was no more snow there was no more snow again in Britain well that was unfortunately taken out it does be down by some rather ambitious journalists and published again in 2010 in December when we all snowed in so we do have snow and we probably will have snow again but the model is a bit more complicated so we have to go on refining our data and refining our model but the greenhouse effect is certainly there a build-up of quite power of the greenhouse gas like carbon dioxide is not a good idea and clearly things have to be done about it but don't worry about it in one sense it's not all bad we're not going to eliminate it completely because we don't need it but we've built that in our climate this incredibly complex sophisticated subtle system that we always take for granted and don't know as any physics there I hope I've shown you that there's plenty of physics there and now I want to move to probably the most complicated device we've all got because I want to go on to the mobile phone I'm just taking a real cherry picking approach to physics here so let's now have a look at mobile phones what is it about mobile phones and how is it that they can simply provide physics as well let's remind ourselves of one aspect of physics physics is partly concerned with maths certainly you studied it early on and here's a piece that we've improved enormously the first portable phones you can see there was developed in 1973 and it weighed a kilogram now I'd like to put that to the vote whether that is actually portable or not doesn't seem very portable to me this is what sort of thing it looked like this guy thinks he's incredibly cool in about 1987 I have two things to note about him not only has he got the mobile phone the size of a brick he's still got a watch now I'm old fashioned I wear a watch but what about incorporation of the tiny people in the mobile phone in fact we took a picture of somebody with a cap this is not a selfie so all these things his poor man couldn't do any of me 25 or 27 years ago so there we are there's a mobile phone when they were first launched and it's items that people might have and very few people were very sensitive and they were not very mobile and here then is our evolution in choosing a mobile phone starting at the far end with a very similar device that we've just seen very big, very clunky no tools on it except the ability to make a phone call which includes it too bad that's what you really want to deal with but compared to what happened when you get down this end and we have a whole variety of devices we have a computer screen we have a whole lot of apps on it much lighter, hopefully miniaturised and able to do so much more and the evolution of mobile phone as a piece of technology is just breathtaking and one of those things is just amazing we don't get out our mobile phones we just look at them and it's silence of wonder and they're just amazing devices and the physics that's gone into them is fantastic the physics of new materials we've got on these modern materials we've got a liquid crystal display and we've got inside batteries operating extremely sophisticated technology and in fact the reason that that phone down there was so enormous and this one down here is so slim but the biggest driver for that is the change of battery technology we now have battery technology that wasn't even available to try and make mobile phones in the 1980s here by the way it speaks to the modern mobile phone I actually don't own a modern mobile phone I own something that's fairly anti-villogian it's not quite two of these on the string but it's that sort of thing and so I have to have a picture of mobile phones to prove I'm in the beginning of the 21st century so there we are here's a mobile phone but you can see all the sort of options that you can get from in what's a very very small and very large device now what is a mobile phone well it's essentially a radio transmitter and a radio receiver and that's probably why those earliest phones look like walkie-talkies because that's effectively what we have only a walkie-talkie operates on a particular radio frequency and our mobile phone operates through cells and some people are called cell phones and the cells are really the important rather clever device that goes with the mobile phone sort of clever really but this is also a very clever piece of work that's being done to develop videos and what happens is we have a whole series of cell networks if you wanted to use radio you can see there are only about 800 radio frequencies radio wavelengths are available so you only have 400 people in your mobile phone and the whole system will be plugged up unless you have this because what happens is that each of these is a cell with an area in the middle and they are now rapidly hexagonal and so when you get your mobile phone out you might be here in zone F2 you start dialing your signal your radio transmitter it's a signal to the mask and your messages are passed on at whatever wavelength happens to be available but you can keep reusing the wavelength because all your neighbors produce exactly the same wavelength without interfering with your call and that's the beauty of the mobile phone and the cell network so the network is needed because there isn't any number of radio frequencies available about 800 which means by the time you've got somebody set up to receive it and then talk about radio cellphones is to make out with people unless we have the cells and by using this we can keep reusing the frequencies and we have to have a lot of masks per unit area we have to have a cell about 10 square miles or get smaller in cities I'm not sure what they are around here but if you haven't looked where the mobile phone masks are they are probably smaller than 10 square miles but cells are really small and by having them close together and able to transmit we are able to use the same radio frequency again and again and this is the mask and these are items of for some reason incredible horror I know the Daily Mail says they give you cancer but the Daily Mail says everything you should cancer if you live long enough you probably have to survive every disease cancer scenario with Daily Mail there is actually zero clinical evidence of any effect measurable and they have repeatedly measured and measured and measured again the influence of mobile phone masks the Daily Mail will suddenly tell you that oh well down on this street they put a mask up and five people die of cancer and they don't seem to know that they might have died of cancer having put a mask up and they look at the spread of cancers and the statistic probability of cancers intelligency ways to go on some people and in this case I'm not going further but we've got to have these things we want to use a cell phone we want to use a mobile phone we have to have these kind of devices they're not particularly aesthetic they do take a bit of looking for normally our paint is nice I'm not sure what the colour is but it's sort of grey and we're going to look out and then we're going to see how many there are and how small the cells are and say particularly only if they are very small this is inside a mobile phone I did wonder about doing a trick I was in a lecture where somebody said that does anybody have a mobile phone borrow it and broke it because of what he'd actually done personally in the audience but the horror of the young people was so great I think they're still in counselling today see a mobile phone broken before you're up I do no idea and there are some things that people could never see and I think that's why anyway, here is the inside of a mobile phone I'm going to pick you way through it but you can see what we've got is an awful lot of complexity and these very, very clever miniature eyes with poems the most important as I say is the battery so we'll come onto that in a second mobile phones must be light that's a memo to the guy in 1973 1kg is too much they actually only use a small amount of power and they can be saying their signals are short distance because we assume these in cells we haven't sent them very far so that's okay but there is a reason for the compactness and that's the battery and the batteries that they use are things like this and again we can look at those and not be desperately impressed but the physics that are designing these batteries is to enable them to pack up or some power punch that they do and the size they are has been phenomenal and they are based on lithium ions lithium ion movement will carry the charge and the beauty of the lithium ion system is you can reverse it so left to the right devices when you connect the whole circuit lithium ions will chunks are out around the battery carrying the charge and powering the phone and when you run out of battery you plug it into the system and what happens is that the lithium ions are pushed back by the charger and they go back to where they started and then when you start running over our phone again they are just discharged and as long as you can keep the lithium ions being either going the direction they want to and then pushed back you can keep your mobile phone battery going for a long time this technology is reversible technology is what's made the difference between mobile phone being chunky house with only phone calls being devices that you can do so much on and also being so light they also as I mentioned in passing contain a liquid crystal display screen and that's again important the original devices they try to make without that technology they try to make out of the numeric display system and they are heavy and chunky and cumbersome and not particularly attractive and so instead they use a liquid crystal display and so the key feature and this is a witness as a warner there's the key feature about mobile phones the focus of this is a huge modern materials which brings you onto the last bit of physics I want to explore which is a little bit about materials and material science and one of the things that's happened to result in the application of physics is real understanding of the physical reality of materials because we've now got some materials with really surprising properties so again materials are things we've taken for granted in the physical world but let's have a look at them essentially we've got three classes of material you might want to argue about the choice but I think this is the exhaustive list classes and ceramics at the top polymers or plastics in the middle and metals you look and say well there must be some things that aren't that well what about wood it's a polymer so naturally occurring in a polymer so it may not be a plastic it might not be a melty but it's a polymer so it comes in a better hand to me so this pretty much comes everything and materials behave differently in general you know that it's obviously I don't know what to say but once we build a car out of wood we'll take it to student in white because of course the heavy is not that strong and there are many other features that are not so attractive about it as well I think heavy is probably the biggest designer against so materials have different properties we're used to the idea and we select materials to the extent we're now thinking about it and I want to think about some properties and materials which can be investigated with an extremely simple physical device and if people told me before they'll know about this my fondness of this device is called a hammer now you might not think this is a device for physics but it is actually you can get an awful lot of information if you hit things with a hammer so here's the start let's have a look at metals now metals quite conveniently will bend here it's actually not a hammer it's a mallet but you don't need to make it now the trumpet piece and so you can bend the metal now it's not always going to be used the metal is going to bend because occasionally people do that sort of thing only the advantages may not be that you're tired of doing this but effectively you can pull that far as a lamppost and you can get the hammers and you can hit out the vents you may not be tired of being a bit weaker but there are some of those bits that could be straightened out in the hammer so you could be back to where you started but glass won't you get that hammer and glass and shaft so it's a different sort of material we're just used to that in that case we won't build our cars out of glass so what's the problem well there are some things we want to do I have some of the properties of glasses so you won't have to think about this some materials here's an example number rubber resists changing shape completely it's an example of polymer actually plastic plastic is a polymer of long thin molecules and because of that you get particular properties so you whack that with that hammer and that hammer will bounce back so some of the materials we've just changed the shape so we've really got three types of material quite used to this idea just investigating with that hammer and what we can see is that the materials that resist bending breaking or ever they tend to call tough and if we add polymers to brittle materials like glavos we can have some surprising results but the first one I want to show you is not glavos but concrete now concrete is a brittle material concrete is rock hard quite used to building things but if somebody came along with the said hammer they would not have to walk well not necessarily it's not the University of Michigan and they've got this stuff they've got polymers in there and they can bend these lumps on concrete this is concrete this is the good ordinary concrete with a blend of rubber so you start to get some materials these are our properties and if you go far enough you can actually make springs out of this stuff and you bounce and spring amazing bending the physics of materials why they break how they go wrong and investigating them with a hammer and then trying to improve them by bending the materials another one is glass now we're used to the idea you take a hammer to your bottle as I showed it will break but here's somebody I don't know if they take a hammer to this they possibly have we're used to the idea having toughened glass in the windscreen of our cars and lots of little shards hanging in the driver's lap it certainly hasn't caused the sort of breakage that the bottle had and so we've toughened it now toughened glass is made by a lamination process you've got two glass two pieces of glass and basically put a sheet of clear plastic between them so just very simply by doing something like that we've changed the physics of the material you might think this is obvious to learn about toughened glass for a long time yes we have but if you go back in a hundred years the idea that you might have something like a windscreen that wouldn't break to bits if you think that a hammer would seem like something close to magic so just again by understanding materials materials physics we've got to this sort of process now glass is an interesting material it's incredibly brittle it's useful but don't mind we've used it for a whole variety of reasons for a long time and true glass is more for satanists to say the atoms and molecules are making up they're quite nowhere to sit so it's around in the ray it's weak and brittle because it cracks itself so if you hit it with a hammer the cracks go whizzing through it and hold it and break itself so we've seen that you could deal with that in our laminated glass but another thing you can do is heat the glass back up again and you can coat the molecules to move to where they'd rather sit down and form them for crystals and when you do that you find you've got something that's got really strong tiny zones and they resist crack growth crack whizzing hits the zone and can't go further so the material is strong and those materials are called glass ceramics and they look like a piece of glass but they are actually called glass ceramics and they have got the ceramic nature too now here's a classic that you can do with glass it's not investigating with a hammer it's investigating with another physical phenomena which is hot water or hot water into a glass hot boiling water into a glass object and you can get this sort of thing happening you can get fractured just like that why? because the interior of the glass heats up expands because it gets hotter and it pushes against the cooler exterior cooler exterior is weak so it cracks and it gives up a glass ceramic you can avoid this problem I'm not suggesting you make glass ceramic jokes although we do have Pyrex which is a very slightly crystalline material it works like other effects but more significantly we've got something like this a glass sheet glass ceramic sheet and it's a hole again it's a very everyday item and people may not realise how well it is you've effectively got what looks like a sheet of glass and you can heat it up to these electrical heaters and it doesn't crack you couldn't do that if it wasn't a glass ceramic you couldn't do that without the contribution of material's physicists you're not only concerned that somebody is here with fries and eggs but actually you're using a fantastic piece of development that we thank physics for ok so, I'm coming to the end now very quickly I hope I've shown that physics is everything about understanding the physical world and if we go right we can probe all the way back to the origin of the universe there's nothing no time scale, no length scale that we're not involved in I've shown, I hope, through the examples that we can use to understand climate we can enjoy our improved communications and we can have better materials so that's my serious confusion for that, I'd like to have one more quote from the man himself Albert Einstein he told us that you should be able to explain the laws of physics to a barman and in a few minutes time very now thank you