 Alright, welcome back. So this is a little bit of a summary slide before we move on to new things. The point I want to make here is that different unstable isotopes all decay in their own special ways. They all sort of decay slightly differently. Carbon 14, which we covered in an earlier video, breaks apart or decays by beta decay. Uranium 238 decays by alpha decay, etc., etc. Different unstable isotopes decay in their own special way. In fact, a lot of unstable isotopes, they decay by combination of different kinds of decays. So you might have some unstable isotope that maybe does 80% beta decay and 20% alpha decay. So things can get kind of messy with these types of decays, but we just present you with relatively simple types of decays just because you don't need to know the super complicated stuff. In case this was not clear, these unstable isotopes are called radioactive isotopes. In other words, everything that we've been talking about when it decays, those are radioactive materials. Why are they called radioactive materials? Well, if you look back at all those videos, there was always some piece of the atom that was getting fired off into the distance. So we say those unstable isotopes radiate parts of the atom. That's basically one of the reasons why they're called radioactive. So there you go. The things that get fired off are genuinely things that get fired off. I'm not lying to you when I say those electrons or those heliums or positrons that get fired off, they genuinely get fired off. You can see them, even though the things that get fired off are really, really small. You can't see them, you can't see the actual particle with your own eye. You can see how far they go with your own eyes using something called a cloud chamber. So I'm going to show you briefly a video. Cloud chamber is basically like a box, maybe the size of a microwave oven. And inside of the cloud chamber, there's a vapor, basically like a mist, if you want. And that vapor is really sensitive. If you just mess with it a little bit, the vapor will condense and you'll see these, it'll condense into basically a mist that you can see, but you can't really see it when it's a vapor. And what they do in the cloud chamber, there's the vapor there, you throw in a little bit of radioactive material and every time an electron or a helium gets fired off into the distance, that thing that got fired off is enough to disturb the vapor. And what you'll see is the vapor will condense along the trail that the electron or the helium that got fired off into, along the trail that that thing made. So if you have an electron that gets fired off this way, the vapor that's all surrounding it will condense and you'll see this little smoky streak. And you can see this with your own eyes. Even though the electron is so tiny that you can't see it, it gets fired off far enough away that you can actually see how far it went with your own eyes. So here's a cloud chamber in action. So here's the cloud chamber. You can see these streaks already from the cloud chamber. Every time you see a streak, that is basically an electron or a helium getting fired off into the distance and you can see this with your own eyes. I think you're going to see someone's hands show up in a minute just to show you how big this box is. There's the person. But that is a cloud chamber. So the stuff that gets fired off by the radioactive materials actually gets fired off quite a distance compared to how big they are. Here is a different kind of equation. This is a somewhat famous equation. It sure looks a lot more complicated. But there's one question mark in the equation. And so I could ask you to figure out what this question mark is. You can certainly do that. You can pause the video if you want and try to work through it. I'm going to work through it here. So we're going to split the equation down the arrow. This time we have more than one thing on the left side. So we're going to add up the weight of everything on the left side. It weighs 236, everything. That means everything on the right side has to add up to a weight of 236. This thing weighs 91. This thing weighs one. But if you notice, we have three of them. So really a total weight of three over there. So 91 plus three is going to get us to 94. So these things add up to 94 weight. So whatever this question mark is, it has to have a weight of 236 minus 94. And if you do the subtraction, you end up with 142. So the question mark has to have a mass number of 142. You do the same thing with the bottom numbers. We've got two things. We add up the bottom numbers on the left side, add up to 92. That means all of the bottom numbers on the right side have to also add up to 92. The krypton atom has 36 of those positives. This thing here has none. So I don't care if we have three of them, it doesn't have any positive charges. So the question mark, how many positive charges does it have? It has to have 92 minus the 36 that the krypton has. And if you do that, you'll see that the question mark has 56 positive charges. And if you look up who has 56 positive charges in the periodic table, you'll see that it's an atom called barium, and the symbol for barium is capital B, lowercase a. So there we go. That was a more complicated type of equation, but it still only had one missing piece. So the same rules applied. We could figure out what the missing piece was by matching the top numbers and matching the bottom numbers on the left and right side of the arrow. This particular equation is famous, maybe not famous to most of you, but it is somewhat famous to introduce what is famous about this equation. I need to talk about this. This lowercase n stands for neutron. If you remember, a neutron has a mass number of one. That's why there's a one here, and it has no electrical charge. That's why there's a zero in the lower left. And this equation says, if I take uranium 235 and I hit it with a neutron, that's a neutron there, one neutron, I can basically split this uranium into two different atoms. I can make some energy, and I get three more neutrons. And some people far smarter than I am realized something about this equation, and they said, look, if I have a big ball of uranium 235 atoms, so pretend there's a whole bunch of uranium 235s in here, and I just tap it with one neutron, just one. Maybe that neutron hits this uranium and it splits that uranium and releases a little bit of energy, but it's also that uranium is also gonna release three more neutrons. And maybe those three more neutrons can slam into another uranium that's sitting around nearby, actually three more uranium that are sitting nearby. It's gonna split, those three neutrons are gonna split three more uranium. They're gonna release three times as much energy, but now you're gonna release nine more neutrons because each of those uraniums is gonna release three more neutrons. Those nine neutrons can slam into nine more uraniums, split those uraniums, release nine times as much energy as the first uranium splitting, release a whole bunch more, I think that's 27 more neutrons. Those 27 more neutrons can hit 27 more uraniums, release more energy, and this keeps going. You release more and more energy until you have an enormous explosion, just by taking a little bit of uranium, tapping it with a neutron or a couple of neutrons, and it just keeps going because you keep making more and more neutrons that can hit more and more uraniums and release more and more energy. And this is basically how the first atomic bomb worked. This is called a chain reaction. You take one uranium, hit it with a neutron, get three more neutrons, get some energy. Those three more neutrons can slam into three more uraniums, get a whole bunch more neutrons, get more energy. And this keeps going until you run out of, until you run out of uraniums, basically. Like I said, that's how the first atomic bomb worked. So what's the big deal with radioactive material? Well, you can release a lot of energy by manipulating radioactive material. If you do it in a more careful way, you can use the energy that gets released to heat up water, and the heated up water can turn a wheel, and that can be used to make electricity. That's how a lot of nuclear power plants work. So radioactive material, you can get a lot of energy out of it. You can destroy things with it. You can also make electricity with it and do other useful things. What's the big deal with radioactive material, part three? Well, this is supposed to be a picture of your genetic material, your DNA. This is gonna be the worst animation you've ever seen, and it's not quite correct, but it's close enough to correct. If you, the problem with radioactive material and people is that the things that get fired off are very often absorbed by our genetic material and other molecules in our body, and they have enough energy that they can damage our genetic material. So this is supposed to show you damage. There you can see that the DNA got cut. And if you do enough damage to your genetic material, you can end up with things like cancer, or you can end up with, can cause birth defects, things like that. So radioactive material can be used destructively for not necessarily good things. You can also use it to, like I said, to generate electricity. So there are useful things as well for radioactive material. And there are also useful things in medicine that involve radioactive materials. I talked about PET scans in an earlier video. So radioactive materials, they can be used for good and for bad. I'm not gonna go into this, I usually talk about this on ground, but basically radioactive materials have been used to kill people. Apparently the Russians seem to enjoy that method. Again, I'm not gonna go into this, but this is a big chunk of radioactive material that was involved in killing at least two people and harming others. And because of that, it's called the demon core. This person here ended up dead because he did not treat this thing with enough respect and he ended up killing himself. But that's for the on-ground class. You can read about it if you want. Here is an example of radioactive material being used in medicine. So I'm gonna talk about a medication that I don't, I'm not even sure this medication gets used anymore. There are other ones that are used. This medication is called Bexar. And if you have ever gotten a prescription medication from the pharmacy, you go there, they give you the medication, but they also give you this sheet of paper with really tiny print that describes all sorts of things that can happen to you. When you take the medication, it gives a lot of detail about the medication. That sheet of paper is sometimes called prescribing information. So what I'm gonna show you is a little piece of the prescribing information for Bexar. Here it is, well, here's some of it. Bexar is a drug for the treatment of follicular lymphoma. That is a blood cancer, so this particular drug is used to treat a special kind of blood cancer. This is more of the prescribing information for Bexar. Bexar contains what, everybody? Well, it contains iodine 131. And what I will tell you is that this isotope of iodine is unstable, and there's another piece of prescribing information. It says iodine 131 emits both beta and gamma radiation. So this unstable isotope does two kinds of decay. In case you're curious, the way that Bexar works is it's basically used to kill off cancer cells. Problem with radiation. Radiation gets used a lot to treat cancer because, well, it'll kill cancer cells if you put enough radioactive material in your cancer cells, the radioactive material will kill the cancer cells. Problem is that radioactive material is also good at killing cells that are not cancerous. And if you kill too many cells that are not cancerous, you get sick and die just from the radiation itself and not necessarily the cancer. Let's pretend that this is a cancer cell, and maybe this one over here is a healthy cell. So you wanna give radiation to the cancer cell and you wanna spare the healthy cell. The Bexar molecules look like they look like a Y-shaped molecule. And somewhere on the Y-shaped molecule, they have stuck the iodine 131. And this Y-shaped molecule is really good at sticking to the cancer cells and not so good at sticking to the healthy cells. So the idea is if you get enough of these molecules to stick to the cancer cells, they're gonna fire off whatever iodine 131 fires off and it's probably gonna slam into the cancer cell and hopefully eventually kill it off. And it's less likely to stick to the healthy cells. So you're probably gonna kill off your cancer cells and not get a sick when you're treated with this drug. That's basically how Bexar works and a little bit of healthcare information as well. So what do I want you to know? Please don't memorize what alpha decay is, what beta decay is, positron, those types of things like that. You should be able to basically look at a decay equation and figure out the missing piece. That's what this bullet point says. You should also know that radioactive isotopes are unstable atoms, you should know why radioactive material can be useful, and you should know why it can be dangerous. And that's the end of this video. See you in the next one. ["Ratomic Bomb"] ["Ratomic Bomb"]