 This video lesson deals with nuclear chemistry, in particular human impacts. We're going to be dealing with, first of all, the procedures, secondly with the effects, and finally with the intensities of these effects. First of all, radiation creates undesirable ions inside the body. These may be simply because of having electrons being stripped away, or in fact, by causing larger molecules to lice into smaller molecules that basically don't belong in the cellular environment. Adverse chemical reactions then will inhibit cellular production of necessary materials. This is very important. It behaves like a poison. It creates species inside of the cell, as I've mentioned, that don't belong there. Additionally, rapid cell division especially will affect skin, sex organs, intestines, and bone. So you can see immediately, they're going to be problems with the surface of the body protecting the inside of the body from the elements, the sex organs from reproduction and normal hormone function, also the intestines from dealing with the processing of food to develop energy, to power the body, and finally bone for structural integrity of the body. The way that radiation can be measured, commonly, is the Geiger counter. The Geiger counter has a gaseous section that then is subject, like everything else in the environment, to this radiation. The gaseous environment will receive the radiation, create ions, and these ions will be accelerated from one side to the other, creating an electric current. This electrical current will then click, and the rate of clicking then will determine the amount of radiation that is being received in a certain general area. Now we move on to the various intensities and the units involved. We'll be using the unit of REM, which was introduced in a previous video. First of all, all food, water, and air everywhere has radiation. As I've mentioned previously, carbon-14 in natural, unstable isotope of carbon is present in every type of carbon-based substance that we see, whether it's wood, whether it's food, whether it's plant and animal life. It is everywhere, but it's a natural fact. What we really need to be concerned with are more intensive sources of radiation. X-rays, scans and therapy, which are human interventions, careful monitoring is in fact required. Let's take a look at this chart starting at the bottom. In particular, the exposure will be given here, the type, and over here, the intensity will be given by the number of REMs. First of all, normal annual exposure is about 360M REMs or 0.36 of a REM. If you just walk around, nothing special, you're out in the rainforest and you live, you're going to get 0.36 REMs from the background radiation. If for any reason you do get 25 REMs a year, that's not going to cause you a problem. That is commonly what medical applications do their best to limit. In other words, if you go in for three or four tooth X-rays a year, you're going to be really safe. But what happens if your dentist does two or three or four X-rays every hour for eight hours a day, so forth, okay? That's why they get the shielding and you don't. Nausea, fatigue, vomit, and white count cell begins to go down when you start to get about 100 REMs in a 24-hour period. This is commonly called radiation sickness. This is very, very debilitating on the body. And another thing to keep in mind is what I've mentioned, this cumulative effect. If the cumulative effect continues, these adverse chemical reactions continue. And you have to consider the fact that bone replaced itself about every 14 years. The intestines don't get helped out. The sex organs don't change much. The brain also doesn't get replaced. You don't get new brain cells. So the point is the cumulative effect of this exposure, there's no reversal of it. Once you get it, you have that level. And at a certain higher level, it's basically game over. So here, you do get this radiation sickness and that's why the people at Fukushima who did go in for limited amounts of time were often called the nuclear samurai because they exposed themselves to higher levels of radiation even though they had high levels of coating in order to prevent others from being subject to the radiation themselves. An exposure of 500 grams will cause death to 50% of the people in the region. And ultimately, an exposure of 600 grams will cause death in 100% of people. How do you protect yourself? Well, there are three general guidelines and these are very clearly codified by different industries. Industry standards are very important for this case. First of all, keep your distance. That might be a distance of 5 feet. It might be a distance of 20 feet and it might be a distance of 100 feet. Time. Limit your exposure. Your exposure might be 10 seconds, your exposure may be 10 minutes and it may be an entire day. And also shielding is important. A small layer of clothing might have some effect. I'm not really sure about that. Go check out your sources. But commonly to shield what you'll do of course is you'll have a heavy lead layer and that does significant things. But things like cinder blocks have an effect against beta radiation and gamma radiation, I believe, is the thing that is stopped by the lead. So there are different materials that stop different types of radiation. Again, distance, time and shielding. And in the industries such as nuclear medicine, there are important industry standards that are maintained. Thank you for your attention.