They turned to me. >> All right. Good afternoon. Before I begin today to points of apology to the class as a whole, went a little over time. Last time there was maybe about ten seconds worth of what I said that got cut off because when the recording is get made, they start and end at the specified times. I have no control, no big deal. We will go over the last ten seconds again when we need to. I think everybody should be able to see in the last video the information they need on the slides. Second has to do with your exams status of your exams to pages graded and returned to me. I'm hoping to get the other two pages later today. If all that happens, I might have them back for you on Wednesday. When you've get them on Wednesday, I'm hoping they won't be too sticky. But something that happened today, one of the unintended consequences of trying to beat better nutrition majors or get a kick out of this. I brought in apple chunks and a container for lunch. Didn't find out until after the fact when I arbitrarily set the plastic bag in which they were down on top of your exams. But there was a leak in both the bag and the container that L at the pineapple chunks. A little bit of pineapple juice went here and there we blotted it up. I don't think it's going to be a major problem, but I will say this, the chocolate croissant that I had for dessert didn't leak all over everything. >> Step where we were last time I was talking about nuclear transmutation. >> Section 20.4, your textbook talks about how unstable atomic nuclei can be converted into stable atomic nuclei by undergoing what's called radioactive decay. And even stable atomic nuclei can be transmuted into the nuclei of other elements, like causing them to undergo nuclear reactions. There are a couple of challenges associated with nuclear reactions. And those challenges are outlined on page 97 in the lecture notes, the title of which is particle accelerators Particle detectors. And here's what that's all about. To get to atomic nuclei, to bump into each other is not a trivial thing for two reasons. One is, atomic nuclei don't generally occur all by themselves. They're parts of atoms and they have electrons surrounding them. And so one of the challenges right off the bat is to get the electrons out of the way. And then even after you do that, getting the nuclei to bump into each other isn't easy because the nuclei are positively charged. And of course, if you bring together two things that are positively charged, they're going to tend to repel each other. The solution to both of these problems is to use some sort of an instrument called a particle accelerator, whose mission in life is to accelerate these atoms to the point where they're moving so fast that number one, we strip away the electrons. And number two, the positively-charged nuclei can bump into each other because they're going so fast that the positive charges don't have time to exert their repulsive force. A few examples of particle accelerators appear in your textbook. For example, at the bottom of page 936, a schematic diagram of a device called a cyclotron. The point is there's a couple of D-shaped, the big magnets here. And generally the way this is done is by using high-intensity magnetic fields and electric fields to accelerate these particles to high velocities. And if you take a careful look at the diagram here, the idea is that the target is over here someplace. And then we shoot a particle in here that zips around in circles until finally it bumps into the target over here. Now the cyclotron was actually the first device that was built that would do this kind of thing. And part of what was attractive about this design is that it's fairly compact and could be built in a room and maybe about the size of the one we're in now. In fact, the first cyclotron was actually built on a handball court at the University of Chicago. Okay, so people got some mileage out of that. Then they figured out that if they really want to get about the business of doing this sort of thing, they need to build bigger, better race tracks for atoms that would allow the acceleration of these particles to truly high velocities. On the following page, there's a photograph of a section of a larger particle accelerator. You can get some sense of how big this is. Because if you look carefully, there's a person kneeling down there doing some kind of a job. And it gives you an idea of how big these things are. In fact, these days these things are on the scale of miles wall, for example. There's the SLAC, the so-called Stanford Linear Accelerator and collider, built on the campus of Stanford University in Palo Alto, California. This thing's about two miles long. So picture just a straight line like this with something at each end that could shoot particles at each other and bang. They collide in the middle some place, except it's about two miles long. There's mentioned in my lecture notes which were written, let's see, Definitely older than you folks aren't. I wrote these things about 990s. So at this point they're sneaking up. I'm 30 years old. One big hot topic project at the time, the so-called superconducting super collider Supposed to be built entirely around the town of lacks a hace, Texas problem is they got the whole dug, then they figured out they were running out of money. So they basically had to fill the hole back in and that never got built. So ignore any references to the CSC in my lecture notes. However, one that has been in the news lately is the Large Hadron Collider at cern in Switzerland in Europe. We can say more about that a little bit later on. But in the last couple of years, they've made a few very fundamental discoveries in terms of some of the interesting particles that make up the universe. Just look up Large Hadron Collider, or LHC on the web and see what kind of interesting stuff we've been doing there. Now, once you bump these particles into each other in some sort of nuclear reaction takes place. How do you know exactly what's going on? Well, there are various ways to detect the new particles that are formed as a result of a nuclear reaction. And various particle detectors have been devised depending on what particular information you happen to be looking for. One of the most famous kinds of particle detectors, the so-called Geiger counter or Geiger muller counter. There were two people who are actually involved in making this thing. Let me just take a quick look in your textbook. And I think they have a schematic diagram of that to okay. Bottom of page 945 shows a picture that looks something like this. The idea is that if all you want to do is find out whether you are in the presence of radioactive material or not. You can use a device like this. There's a little window that you can wave around and see if it registers any radioactive material. And how it does that is that if something is giving off radiation, the radiation passes through this little window, makes contact with the electronics inside. And when it makes contract with electronics, there's a change in the electric current that's measured by the instrument. So the point is it does have some kind of an electronic response so they can use to detect the radiation. That's their. Most people think about the older kind of Geiger counter that actually made a clicking noise would have encountered radioactivity. And the frequency of the clicks would have to do with how radioactive source once. >> If it was just going click, click, click once in a while, then it wasn't that radioactive. >> But who was going click, click, click, click, click, click. Then you had a pretty hot radioactive source there. So that's basically what a Geiger counter looks like. Something called a cloud chamber is more of used to the kind of physicists who do this kind of research. The best analogy I can give you here is everybody's seen the vapor trail that is left behind when a jet plane goes by overhead rate, that vapor trail is left by particles of water, water vapor crystallizing out on the jet. Whoa, and being left behind, essentially looking something like a human-made cloud. Same sort of deal with the cloud chamber. That's a box that's been saturated by vapors of oil or things like that. And the point is, as particles travel through it, they leave their own little vapor trails behind. Can be photographed. And then the point is, people who do this sort of research can take a look at those paper trails. And by measuring the velocities and the trajectories of these particles. They have some idea of what kind of chemical reaction is taking place, a scintillation counter. Now, here is one of the most common misconceptions about what happens when people get exposed to too much radiation. People think that if you get too much exposure to radioactive materials, you glow in the dark. That's not true, and you get too much exposure to radioactive materials, you get cancer and die. But that's another story which will tell you about shortly. But the reason people think that, and I guess my own wristwatches demonstration of that is n e. This is a glow in the dark wristwatch. If I darken the room here, you might be able to see the little indicators for the numbers at the hands themselves glowing in the dark. Well, where those things came from is the idea that they were painted with a radioactive material. But the radioactive material itself is not what loads they mixed it in with something like zinc sulfide, which does tend to glow when radioactive particles strike it. The point is that glow that's produced on a material like zinc sulfide. When a radioactive particle strikes, it is called a sin tiller of light. And a scintillation counter is a device that counts these until is that light that are formed when radioactive materials strikes something like the zinc sulfide. So you do not glow in the dark from getting too much radioactivity, but we'll say more about that later. Perhaps more interest to most people is okay if I find myself in some kind of a profession or some kind of a situation where there's going to be high exposure to radioactivity, am I getting a big enough dose of radioactivity to do myself damage, that's where something called a badge dosimeter comes into play. Now, among the people who fall into this category, certainly people that work in nuclear power plants would fall into this category. But even people who weren't exposed to x-rays on a regular basis, people who work in hospitals in the radiology department or people who work in dentist's office, they're always taking X-rays of your teeth. And dental offices, even people who travel a lot, spend a lot of time flying around at 35 thousand feet. Well, there's that much less of the atmosphere between you, your fly, and people who are down on the ground. So you have an increased risk of exposure to radiation from outside the Earth. Anyway, the point is you're concerned about this. You can wear a little badge dosimeter. It's just a little badge that you would wear on your lapel or something like that. And inside the dosimeter is a piece of photographic film. And the point is photographic film tends to darken when it's exposed to radiation like this. So the point is that you do work into something like a hospital or a dental office. You should be wearing something like this full-time. And then once every six months or so, somebody from the Nuclear Regulatory Commission comes around, collects than us emitters, examines the film inside, see how dark it is. And then a week or two later you get a report back that says things like, okay, you're fine, you're fine, you're going to die next week. >> You're fine, you're fine. >> Usually not that severe, but you get some sense of how much radiation you've been exposed to. So speaking of which, how much radiation is too much and how do we go about measuring radioactivity? Well, again, several ways, depending on what particular information you're interested in. The fundamental unit of radioactivity is referred to as the Becquerel, named in honor of a French scientist by the name of Henri Becquerel. Basically what the Becquerel is, is one, the disintegration of an atom or one that radioactive decay event happening per second. So again, thinking back to the Geiger counter for a moment. If you set up your clicking Geiger counter and it goes click, click, click, click at the rate of one click per second. That's one Becquerel of radiation are more commonly used unit equivalent to 3.7 times ten to the tenth. >> Becquerels is named after. >> Anybody recognize this name? >> Just look familiar at all because it's named after Yeah, but I'm Maria split off SGA Curie with her husband. >> Pierre did a lot of work in the area of radioactivity and radio isotopes at the Sorbonne in France. Marie Curie is the only woman to win two Nobel Prizes, and she has a couple of elements on the periodic table that she discovered, radium and polonium. The 3.7 times ten to the tenth becquerels has to do with the fact that that's the radioactivity level of one gram of radium, which she discovered. She also has the element Curie. I'm on the periodic table, which is named for her. Also the radioactive element polonium is named for her native Poland. One interesting sidelight to history to know, I said before that you get exposed to a lot of radiation, you develop cancer and die. No surprise, Marie Curie eventually develop cancer and died, although she did live to a ripe old age. Before she did that, her husband Pierre, who was in the lab with her, died in a fall from a bicycle. >> Life Is Strange again. >> What most people care about, am I getting enough radiation to do myself some damage? What are the fundamental units of radiation dosage? The range can is named after a German scientist by the name of Wilhelm Rontgen who discovered x-rays and gamma rays. The rent going is the fundamental unit of radiation dosage for gamma radiation. In fact, let me just look up where this is in the lecture notes and just quickly recite the definition of the Rontgen. On page 98 in the lecture notes. It says the ranking is the amount of gamma radiation needed to ionize to 0.08 times ten to the ninth air molecules per milliliter of air at standard temperature and pressure. Now I don't care if you know that definition or not, except to notice that it's using Gamma rays to make that designation. And we'll say more in a few moments about why gamma rays were probably a good choice there. But the point is there are other kinds of radiation as well. And most people who are getting exposed to too much radiation don't care whether the damage is being done by alpha rays or beta rays or gamma rays or positrons or what have you. They just want to know what kind of bad shape of my about to be in. So an equivalent the rim called the RNC and equivalent it man, that's where the abbreviation REM comes from, is the equivalent to the rent again, but for any kind of radiation. In other words, how much damage to biological tissues is this doing? Now let me just go ahead and show you this one slide that will give you some information about how much risk most people happened to be at. Here we go. >> Let me wait until everybody's done copying this for just a moment and we'll go ahead and show you this slide, everyone. >> Good. >> Okay, let me go ahead and show you this other thing now. >> What this is a diagram of is where we get our exposure to radiation from just walking around on earth and doing the things that we normally bit. And most of these things are presented in M REMS, which is milli rams. Alright, let's talk about where some of these things come from. Natural sources. Okay? There are radioactive materials in the rocks and the soil. So no matter where you go to a small extent, you pick up a little bit of radiation just from walking around on the surface of the earth. There are cosmic rays bombard the Earth constant for the most part. The atmosphere screams out most of the damage that a little bit makes it through. And so we are all constantly being irradiated from outer space. Each and every one of us is walking around with radioactive isotopes in our bodies, which means aunts were all gathered here in this room. I'm irradiating you, your irradiating me. But again, these things are measured in milli rams. Not that big a deal. Human-made sources, medical x-rays, we talked about this a few minutes ago. How much exposure to x-rays depends on what you do for a living, depends on how much time you spend at hospitals or dentist chairs. >> Nuclear medicine. >> We're going to talk a little bit, a few minutes about some of the treatments that radioisotopes are used for beneficial purposes to hopefully help people feel better and cure certain diseases. And there are certain consumer products like my radioactive wristwatch that provide a little bit of radioactivity. The point is, if you add all of these things up, it comes to about maybe a 150 milligrams per year. That's generally considered pretty sick. In fact, anything under about 500 milligrams per year Generally considered pretty safe. If you find yourself in situations where it might be higher than that, then it wouldn't be a bad idea to go get tested for things like this. Now you'll notice that I've left out this one right over here for the moment, which is the tallest peak on our graph here. This listing here is for radar. You've heard of radon, and if so, what do you know about it? Right on sound familiar at all? If not, that's okay. Let me tell you a little about where radon comes from. Suppose this happens to be your helps. Suppose this happens to be your basement. >> Suppose it's your bad luck to be in a house that's on top of a uranium deposits. >> And there are parts of the world where this is a significant thing. >> Well, here's what's going up to show you this other slide. >> When we first started talking about nuclear reactions, that how to write balanced equations for them. We showed that uranium-238, and what this graph is, is it shows what the element is in terms of its atomic number on the x axis versus its mass number on the y axis. So here's uranium 238. But we pointed out before that uranium-238 undergoes alpha emission to form. Thorium 234, which then undergoes a beta emission to form a proto lacked any 2.3.4. Well, the point is on this diagram, each blue diagonal arrow represents an alpha particle being given off. Each little red horizontal arrow represents a beta particle being given off. And the point is, starting from uranium-238, which is radioactive, through a series of alpha and beta emissions, we eventually get down to lead to six, which is a stable isotope. >> Ok, fine. >> Now for the most part, this would be no big deal because for the most part, everything you see here is a metal, which is a solid which remains undergrad with one notable exception, radon 20-20. To find radon symbol are in on a periodic table. And for anybody who's watching at home who doesn't have handy access to a periodic table, I'll help you. Whereas right out of the periodic table, and that's the important point. Radians right here. Radon is a noble gas. So the problem is, unlike all those other metals which are solids and which remain buried well under your basement. It is not inconceivable that when this radioactive decay process, a little bit of radon gas could seep up into somebody's basement and then undergo further radioactive decay to form first, polonium 218, and then everything else. And the point is, if all of this is happening in your basement and if you happen to be walking around in your basement and breathing this stuff, and then all of a sudden these things are happening inside you and this creates a problem. Now again, depending on what part of the country you're in, depending on where exactly your houses built, this might be a big deal. This might not be a big deal. A number of years ago, on a warm summer's day, my wife and I were out for a bike ride around New Castle County and we took a rest stop in somebody's driveway and we noticed that there were a whole bunch of work crews doing things in there. And so I decided to just talk to somebody and say, hey, what do you guys do? It, they said, oh, we're getting rid of radar and he's people's basement. I said, Okay, that's interesting how you do it. It is o we got big fans down there and we're just blown it out into the two, which I said. Okay. So in other words, you're taking care of Radon for these people and giving all of New Castle County radon problem. There are better ways to remediate radon. More importantly, if you're concerned about radon in your basement, you can go to any hardware store like Lowe's or Home Depot, buy a radon test kit, which you can put into your basement and see if you have a radon problem. But the point is it is possible, depending on where your house is located, to get as much as 200 milligrams per year from exposure to radon. Again, hopefully not enough to put you into the danger zone. >> But if you are concerned, you can test for this, which brings us to a good point to segue into this slide. >> So the point is thinking about things like radiation, radioactivity can be kind of scary and in certain context, yes, but it should not be overlooked that there are certain beneficial uses of radioactivity that people work with every day as well. We sent before they get too much exposure to radioactivity. The problem is not that you blow, the problem is you get cancer and die. >> Here's what happens. >> We said before the original definition of the rim focus mostly on gamma rays. There are two reasons for that. Gamma rays have a great deal of penetrating power. That is to say that gamma rays, which are composed simply of photons of light, can be readily absorbed through human tissues. In fact, many of them probably pass straight through as opposed to alpha rays and beta rays, which are actually made of matter and don't penetrate quite so deeply, you don't really have too much to worry about from alpha rays if the source of the alpha rays is outside you because they really can't penetrate human skin very well. So they just get wiped out. The first layer of your epidermis. But if you're breathing in that radon that's in your basement, and all of a sudden those alpha rays are being given off inside your lungs. That's a much more severe problem anyway, back to the gamma rays. What do gamma rays do? Well, gamma rays are referred to as ionizing radiation, which means if you have some atom X here surrounded by its usual octet of electrons, and it encounters a photon of gamma radiation. What that gamma photon tends to do is knock an electron off an atom X to create an island that looks like this. Here's that electron over there. But the point is that's why it's called ionizing radiation. It makes ions that looked like this. But this is a little bit of an unusual line in the sense that it now has an odd number of electrons in its valence shell. Things like these that have an unpaired electron somewhere in their valence shell are referred to as free radicals. Have you heard of free radicals before? >> What do you know about them? >> Bad reputation, right? Nasty little critters. Part of the reason they're nasty little critters because of the octet rule. The octet rule, as you may recall from Chem 101, says that atoms like to have eight electrons in their valence shells. Isn't only S7. So now that it's been generated, it wants to find something to react with. Free radicals are very reactive little critters, and they will latch on to whatever they can find. You try to react with something else and get that eighth electron back. And if they went, they happened to find is your DNA, then all of a sudden, that's where mutations come from that generate cancer cells. This is part of the problem. So the point is, gamma rays in particular are nasty More so than alpha rays or beta rays, but they can do damage to. And now having scared everybody, let's talk about some of the good things that radiation can be used for. Because there are any number of applications of radioactive isotopes for medicinal purposes. Among those possibilities, nuclear medicine can be used for diagnostic purposes, trying to figure out either what's wrong with somebody or what the specific mechanism of that person's medical condition happens to be. And they can be used as what are called radioactive tracers to follow the progress of particular molecules through the body to see how they're being metabolized, or are they being metabolized properly or improperly or what's going on. One example, vitamin B 12. There is a medical condition called pernicious anemia. People who have this condition suffer from a vitamin B12 deficiency. It's not so much that they're eating the wrong foods. It's at their bodies aren't properly metabolizing vitamin B 121. Way to diagnose this problem and maybe try to do something about it, feed that patient. A sample of vitamin B12 weld that is enriched in the radioactive isotope of cobol. Naturally occurring vitamin B12 contains cobalt, does not radioactive cobalt. Cobalt has a radio isotope, cobalt 60. It is a beta emitter and can be used to track the progress of vitamin B12 molecules through the person's body. So the point is, if you feed this person the sample of slightly more radioactive vitamin B 12, that can be used as a tracer to try to figure out what the source of the pernicious anemia is and maybe try to do something about it. Certain forms of radiation can actually be used to treat conditions. For example, there's a condition of the thyroid gland called Grave's Disease. Back when George HW Bush was president, both he and his wife Barbara Bush, suffered from Graves disease. The solution to this problem was to feed them a sample of potassium iodide enriched in the radioactive isotope of iodine, which is iodine 131. The point is any iodine ingested by the human body winds up going into the thyroid gland. Turns out that if you feed the person radioactive iodine, when IT reaches the thyroid gland, it bays the thyroid gland in the beta radiation basically kills the source of the disease. And the half-life for iodine 131 is relatively short, about eight hours. So after about two days, let's say most of the radioactive material has gone and you're back to normal. You just don't have a thyroid gland anymore and so you have to take pills for that. But the point is it's a lot better than dealing with the disease. So that's one example of a disease that can be treated using that condition concepts make sense. >> Okay? >> There's plenty of other examples of this sort of thing mentioned in your textbook. Notably on page 945, they talk about isotopes and medicine. By the way, this picture over here is kind of interesting. On page 945 at the margin, they show you two brain scans usually done using what's called positron emission tomography or a PET scan for short. The point is, when you look at these pictures, which actually I just realized for the first time, they've done up in blue and gold. So very U of D pictures here. But the point is there's a lot of gold in this picture. The yellow colors represent activity in the brain as opposed to this picture, which has a lot less of the yellow. That's the picture of someone who was suffering from Alzheimer's disease. The point is you can use brain scans like this to detect areas of inactivity in the brain and try to find out what the problem is and hopefully do something about it. So again, this is one way of using this as a diagnostic technique. And there are plenty of other examples talked about both their added Section 20.8, the title of which is biological effects of radiation Something else that radioactivity is good for is determining the Age of various artifacts. And one example of that is reflected in the handout that we gave out today. After you graduate from this institution, you will get more copies of the University of Delaware messenger that you want to have anything to do with each of which will be accompanied by a request for money. But that's something that awaits. A few years down the line. This particular article, which was an article about the interesting things that UT alumni and alumni are doing, has to do with a lady named Susan from board. She is actually the daughter of one of our former faculty members here in the chemistry department. And as you can tell from the title, carbon researcher is in her element. Well, basically one of the things she works with is radioactive carbon. And using the idea that the rate of decay of radioactive carbon, excuse me, can give you an idea of how old certain artifacts on. Let me describe how it works. Much of the atmosphere is made of nitrogen. Normal nitrogen is nitrogen 14. In the upper atmosphere, there's a lot of free neutrons floating around. When a neutron encounters an ad about nitrogen 14, it converts it into nitrogen 15, which is a radioactive isotope of nitrogen. When nitrogen-15 undergoes radioactive decay, it forms carbon 14 and gives off a proton in the process. Carbon-14 is a radioactive isotope of carbon. Now, the difference, of course, is that nitrogen is a gas, but carbon is a solid. So when some carbon 14 starts forming in the upper atmosphere, it starts falling back towards Earth and eventually encounters oxygen in the atmosphere. And it reacts with the oxygen to form carbon dioxide. Except this is radioactive carbon dioxide because the carbon atom is still carbon-14. Now we all know what carbon dioxide is, right? It's the gas that we breathe out in plants breathe. Then we add this wonderful symbiotic relationship with the plant kingdom. >> Our waste product, CO2 is their food, their waste product two is what we breathe. >> So the point is, as carbon-14 based carpet dioxide piles up in the atmosphere and eventually enters the food chain. I have no idea what kind of organism this is supposed to be. Let's just say it's an herbivore. >> Okay? >> When radioactive carbon-14 winds up in the grass and the plants and his fed on by herbivores. Then the point is the organism has radioactive carbon-14 in its body as well. And the point is, the amount of carbon 14 in the organism's body remains relatively constant over time. It does undergo radioactive decay, which would tend to decrease the carbon 14 concentration. But the organism keeps eating, which replenishes the Carbon-14 concentration until such time comes as the organism isn't eating anymore, because the organism is now dead. And the point is, once the organism is dead, it's not replenishing its Carbon-14 anymore, at which point, the level of carbon 14 in its body tends to decrease. The half-life for carbon 14 is about 5700 years. I trust you remember the concept of half-life from earlier this semester when we were talking about kinetics. Half-life is the time required for half of the reactant to react. The reason half-life is commonly used as a concept where we're talking about radioactive decay processes, is that all radioactive decay processes follow first-order reaction kinetics. And all first-order kinetics processes have a constant half-life. So the point is, for a sample of carbon-14, if you 85,730 years, half of it goes away. And the point is, if you know what the half-life is, you can measure the radioactivity level for carbon-14 in any carbon-based artifact. And use this information to try to get some information about the age of that artifact. For example, let's take a look at the problem that's presented on page 100 and the lecture notes where so-called radiocarbon dating is discussed. Everybody have what they need here. Everybody grow on a better picture of whatever that organism is that I did. Okay, so here's one example of such a problem. And this is kind of like the research that Dr. Trump board does in living tissues. The carbon-14 radioactivity level is 0.255 becquerels per gram of tissue. But in a skull fragment unearth by an archaeologist, the carbon-14 level is only 0.016 becquerels per gram. How old is that skull fragment? Way. >> And if you remember some of the things we talked about earlier this semester, about what the impact is that having a constant half-life to work with this actually isn't that hard a problem because the half-life is constant. >> So what that means is after you eat one half-life, you're down to half of whatever you started with after you ate 2.5 lives, you're down to half of that or a quarter of what you started, which after three half-lives, you're down to half of that or an eighth of what you started with and so on. >> So >> Starting from the carbon 14 radioactivity level in living tissue, 0.255 becquerels per gram. After one half-life, you'd be down to 0.1 to eight becquerels per gram after another half-life, 0.064. After another half-life, 0 32, after another half-life, 0.016, which actually is the radioactivity level of our skull fragment. So what this information tells us is that our skull fragment is for carbon-14 half lives old. And then if you know the value of one carbon 14 half-life, you can figure out how old the skull fragment is. So you basically just multiply the half-life of carbon 14, which is 5 thousand similar 30 years by four. And you find out that your skull fragment is a little over, well, almost 23 thousand years old, 22,920 years old. Out of curiosity, I was just looking at the article that appears on both sides of the handout, there's a brief mentioned made here, something called the Shroud of Turin. Does anybody know, remember what the Shroud of Turin was, is, was thought to be why anybody cares about it. That sounds familiar at all. This may remain a controversial point. Can probably Google the Shroud of Turin and find out more about it. But suffice it to say this, the Shroud of Turin was a piece of fabric discovered in Turin, Italy. On the piece of fabric, which is a pretty good sized piece of fabric, There was a life size image of a man. And a lot of people thought for a long time, just looking at this thing, that this might have been the burial cloth of Jesus Christ, which is an interesting topic to talk about now that they were just coming back from having celebrated Easter yesterday. So the point is, people were rejoicing in the fact that they had discovered this artifact. And then people started to ask questions like, okay, is this really the burial cloth of Christ? Because if so, it should be about 2 thousand years old. And so in principle, if somebody could do a carbon-14 analysis, like we were just talking about and trying to confirm the age of the shroud. Well, for a long time, the Catholic Church was very reluctant to let anybody examined the shroud. It was a holy figure after all. And eventually they relented and gave up a small sample of the shroud for analysis. And it was actually Dr. Tom board who did some of that research. And the conclusion that will come to you with the fact that it probably was not the variable price because the shroud only turned out to be about 600 years old as opposed to about 2 thousand years. The point does remain somewhat controversial because some people are questioning whether the sample was obtained directly and things like that. So you may hear more about the shroud of terrain as time goes on. But that's one application of carbon 14 radiocarbon dating, as it's called, and how it might impact the news cycle that you might see on any given day. I didn't have a little bit more to talk about, but we're down to the last few minutes and so I don't want to rush through it. So we will finish up on Wednesday talking about Chapter 20 in your textbook. And then move on to the next things we're going to be talking about, which has to do with some of the descriptive inorganic chemistry of some of the more common elements. So hopefully on Wednesday we'll have your exams back for you and then we'll do that. >> Now, let me tell you, why wouldn't you since I ran a little over time last time, I thought I read a little under time today. >> Oh, interesting. Well, I didn't really celebrate your per se, but high or whether it's not doing a whole lot. Yesterday, usual things went for a bike ride. >> Adults verbal, if you use a rabies in Italy and my brother studying abroad. I didn't go like all my friends. >> Attenuated church locally. >> Yeah. Armed camp that I'm doing. >> And just about every weekend these days, my father is going to be eight years old next month. He's reached the point where we really live by himself and course facility. And my sister and her husband and I are going through the house getting rid of all kinds of stuff and yeah. >> Cleaning out the added fighting out. >> You know, what's up there that we want to keep and what do we want to throw away? >> Yeah, my father being one of those folks who grew up during the Depression. >> Those votes, not through anything. Yeah. >> So there's a lot to go through this past weekend. We found a lot of my old college textbooks or books that I read when I was a kid. >> It's quite a collection. >> I think she she would definitely yeah, let's go there. But getting back to the it, what do you think?

chem102-010-20170417-122000.mp4

From Dana Chatellier October 11, 2018

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