 Radiation is measured using some sort of Geiger-Mueller counter. This is the old fashion kind that you see in your science fiction movies. Here the the tube is here. If we open it like this then it's exposed to the atmosphere and if you look at the reading here there's going to be a little bit of background so there should be some some small reading so you can see that normally there is some radiation. If we put it near a source you can see that it that needle is going to measure the nuclear decay but it doesn't record it so we're going to put this aside and we're going to use a computer so that we can store the data. So what you have here is the radiation detector and it's got the tube inside here just like we saw in the in the old-fashioned kind and so if we hit collect we're going to collect data for about 60 seconds and this will give us our normal background radiation. So each blip is one count so far we have one two four five six seven eight so this was actually two counts and what I'd like you to notice is with radioactive decay it's not like clockwork so that it's one two three it may be a burst and then a lull and then another burst or it you know as you can see here we had two at one point then we had in succession we had three so this we want to do is to do this a number of times and then take the average because you wouldn't want to take just one reading but for purpose of looking at the different values we're going to only do one test so we're going to save this now we know that there's normal radiation and what's what we call background I'm going to run it again and this time I'm going to put a source that I know to be somewhat radioactive and we'll compare it to our background so really if you wanted to give the actual value you would take subtract the background from the next reading we're going to get so I'm going to say collect and I want to put this on the same graph so what you see I have here is a bag of fertilizer now on a bag of fertilizer you see three sets of numbers the first one tells you how much nitrogen is present the second one how much phosphorus and the third how much potassium when when you are getting your fertilizer the potassium for the fertilizer you actually get it from rock and you and grind up potassium rich rocks also in that potassium you will find a radioactive potassium which is potassium 40 and a little bit of rubidium for the phosphorus that those rocks are going to contain uranium and thorium so just because of the natural occurrence you're going to get some natural radiation so look at the blue in comparison to the red all right let's look at another source so we're going to add also to this graph and this time we're going to use the mantle from a camping lantern and these mantles are made using thorium salts saturated in a cotton fiber and the reason that the camping lanterns are using the mantle is because when you burn the fuel that's in the lantern you don't get very much light you get a little yellow for some fuels and blue from other fuels but if we use the mantle it does a couple of things one it makes the flame smaller and concentrates the light and it gives off a white light rather than the the blue or the yellow from the fuel another source that you'll find around the house is a smoke detector now I've taken the smoke detector apart and inside here there is a little small amount of amyretium and that amyretium is radioactive and it's going to emit and if there's smoke in the way the detector is not going to pick that up and it's going to sound an alarm so let's let's record this amyretium is an alpha emitter and also some gamma since we we can see already how much more radioactive it is I wanted to also show you what happens if we just put a piece of paper between the counter and the source you can see that with alpha particles it's very easy to block so the smoke detector that you have at home has a plastic coating on it and the alpha particles are not going to actually escape so you don't have to worry about the fact that you're going to be exposed to high radiation so you can see that there's lots of sources of radiation around the home and you can see from our observations here that we can measure using the radiation monitor the amount of radiation in the air