Hello, today we're going to talk about irradiation and contamination. So firstly irradiation. Irradiation is when a personal or material is exposed to radiation. So irradiation is when a personal or an object is exposed to radiation. There are three main precautions for this. One is the use of lead lined boxes to store radiois tapes in. Another would be using barriers that people can stand behind whilst either whilst working with radioactive sources or being near them. Such as if you had an X-ray. It's not really a radioactive source but it is ionizing irradiation. You'll have noticed that the radiographer goes and stands behind a lead line barrier before activating or turning on the X-ray machine. Third one would be the use of remotely controlled arms. So this is literally you'd use a joystick to control a robotic arm so that you don't even have to be in the same room as the radioactive source. Ok, so that's a radiation. Contamination is where unwanted radioactive particles get onto or into a material. We then say that that material is contaminated. Contaminating those contaminating atoms later release ionizing radiation which could cause you harm. There are two main kinds of precautions for this sort of against contamination. The first one is that you'd be using gloves and tongs to handle radioactive sources. This keeps or prevents any of the radioactive material from getting underneath your skin or under your nails where it would stay for a while. Just to give an example of what I mean by contamination. If you have your radioactive source here, if you're using it bare handed, when you walk away from it you could easily have a dust or powder or a small remnant of the radiation. It's a small remnant of that radioactive source stuck to your fingers which you will then carry in with you. The other precaution you can take is more used in industry than it would be used in schools. If you're using a very powdered or very brittle material in industry they might wear protective suits. These suits are to prevent you from breathing in any of the material which is not an issue with the sorts of radioactive sources that we use in schools. Which are more dangerous? Well, outside the body you'll find that beta radiation and gamma radiation are the two most dangerous because they can penetrate into the body and can reach the delicate organs and therefore could can harm them. On the other hand, inside the body most dangerous are alpha. Because alpha sources, if they reach inside the body, all of their damage is done to a localized area and what you have inside your body are those delicate organs. So they can be much more dangerous if they contaminate inside your body than outside. The last thing I'd like to say is just the role that peer review has in all of this. So the more we understand how different types of radiation affect our bodies the better we can protect ourselves when we use them. This is one of the reasons why it is so important that research is published. The data in when published is peer reviewed and can quickly become accepted leading to many improvements in our use of radioactive sources and keeping, therefore keeping people safer. Okay, I hope this has helped. And I will see you on Monday.