Wie Radioaktiv sind CAESIUM und URAN? FH Aachen Nuklearchemie [𝟰𝗞] | JJChemistry

Welcome to the next video here from the nuclear chemistry in the FH Aachen. Felix is again next to me, who also made the long video where we went through the laboratories with us. Today it's about the question of how radioactive certain substances are. For this I brought with me cesium, the most reactive metal in the world. A video with a lot of views has also raised a lot of questions, so actually only one. And the loudest is cesium is not radioactive, we will check that today. Then we have potassium, you may know the rumor that bananas are radioactive. That would lie on potassium and we will look at that today. And the third would be bismuth, because bismuth is the first element in the periodic table, which is no longer listed as radioactive. Fourth, we have an uranium mineral, we'll show you that in a moment. But before that, a short introduction for those who may not have seen the first video. Hello, I'm Felix Schneider, I'm the laboratory engineer for nuclear chemistry here at the FH Aachen. Yes, short and crisp. Now we go to the next one, to the measuring devices. First, let's take a quick look at what kind of activity is here in the environment. Mainly from the ground or ... Let's turn it on for that. Now you can hear it. So the normal radioactivity that is always and everywhere. Shall we hold it over there? If I hold it over there, then we are closer to it. Let's see, I'll just hold it like this and see if anything changes. But you can hold on. Actually, the values are the same, right? Otherwise you wouldn't measure potassium. We have the paraffin oil and the glass in between. However, since potassium is very weakly radioactive, we do not measure it very well. That's actually strange. One would have expected a little more to be detected. There must be a reason for that. It is related to the half-life. Please explain that again. There is a nice board in front of it. You can see it quite well. Potassium in the natural isotope mixture consists of potassium-39, potassium-40 and potassium-41. The number below is the percentage of potassium isotope. That means that the potassium that we see, which is also thrown into the water, consists of 93.3% of potassium-39. However, this is not radioactive. The largest part of it is not radioactive. The radioactive isotope is potassium-40 and that only occurs at 0.012%. So it's very low. And what about the half-life? Unfortunately, it is very difficult to read. That's 1.2 x 10 to the power of 9 years. So in the range of billions of years. That means that potassium-40 only decomposes within several billion years. That's just not enough to be able to detect it properly with such a measuring device. Exactly. Next sample, I would say. The next sample would be caesium. I'll hold it over it. So with caesium you actually don't see any change at all. Everything stays the same. This clicking or beeping hasn't changed at all. It's just not radioactive. With that we would have clarified the question from the video. Caesium, and that's why I was able to work with it. There is a radioactive isotope, that's 137. There it is. What we have here, the little dot in the middle, is caesium chloride. Caesium-37. 137. And just to prove to us that it also works. You can definitely hear it. It already sounds a little different. And also this value increases. So it's a beta-ray. Caesium is a beta-ray and has a ... Okay, then we have clarified this question. And at this point I wanted to say one more thing. Thank you very much to a colleague who made the caesium available to us. The name of the YouTube channel is It Warns Tinkering. He produced this caesium and injected it into this ampoule. Thank you very much for that. I would like to explain this again in one sentence. This is a lead thing. I would like to explain this again in one sentence. Because you go there and then you think, why are they going there? Radioactive substances such as gamma rays are stored behind lead. To protect us from the radioactive substances. Exactly, and that's where we always go. We run to this bowl where this lead coating is. Each block weighs over 10 kilos. And that protects us from radiation. The next sample we have is an uranium mineral. Which looks beautiful, by the way, I think. And that's where the mail should go now. I'll put it on. Yes, you can see it too. 1.92, in this case 1.5 kilos. I'll put it on again. Yes, that's pretty ... Quiet. That's pretty clear. Apparently a good ... What value would that be? The beta value, apparently. Wait a minute, beta. Yes, a good beta beam. Yes, there are also beta beams in it. Since uranium is a decaying species, we have several decaying species here, as we can see. If we were to go closer, we would also measure alpha. But then we would contaminate the measuring device and that wouldn't be so good. Yes, okay. So what we're directing here with this uranium mineral is not just uranium, but also decaying products. If uranium is decaying, which substances are still decaying? What we are currently measuring with this device is mainly protactinium-234m. This is one of the decaying products and thorium-234m. Okay, so just other elements that cause this beta radiation. Next, bismuth. Bismuth. If we look at the periodic system here, we can see the number 82Pb, which stands for lead. And next to it is bismuth. And that's the limit. Then all these radioactive things start. Polonium, radon. Yes, and that's why we're going to put bismuth under the test to see if bismuth still radiates. At least so much that we can detect it ourselves. Here is the block. A very nice colored metal. This is the colored rust of the bismuth. But that's not what it's about. I'll put it back on here. And also in this case. As with the first and second test, we have potassium and cesium. You can't detect anything here except the normal background radiation. Underground noise. How do you call it here? Underground. Yes, okay. So you don't measure anything other than what's already in the air anyway. A short and important introduction. Because I have delivered a misinformation. Bismuth is not non-radioactive. So it is radioactive. Since 2003, all bismuth isotopes have been considered radioactive. Since it affects all isotopes, it also affects the bismuth isotope that occurs most often. What you also see in this one kilogram bar form in the video all the time. But now comes the jumping point. The half-life is 19 trillion years. That's a particularly long time span if you keep in mind that our universe is not even that old. Yes, that means we practically have no chance here in this video. To measure with the measuring device given to us. Because it just has to be damn sensitive for it. And yes, that was an important piece of information. I didn't want to withhold it from you. And now have fun with the rest of the video. That would have answered the question. Perfect. So bismuth is not detectable. And our measuring device. Yes, at the end we will do one thing that I am personally interested in. Namely what happens if you just hold this measuring device over here. The result is also clear. It goes off. Who would have thought? For this reason, you always store sources far away from you. If you don't use them. That would also be the students in the internship. With the directors of their workplaces. Yes, exactly. This is part of the degree program here at FH Aachen. As a bachelor's and master's degree program. We have already talked about this in the last video. You can also see all the rooms here. We not only have the laboratory in this room. But also the warehouse. The intermediate warehouse was shown. Who is interested in this video. I will link that at the end. You can click on it. Then you get all the information that is important and interesting. And that deals with nuclear chemistry. Thank you very much for letting me be here. Very nice. We will now shoot another video. Then we'll see you again in this video. Or in the one we shot here as a laboratory. Have fun watching.