Hi I'm Steve Jones and I'm going to tell you something about Hydrogen. Now either I could tell you what it looks like but that would be difficult because you can't see it, or I could tell you how it's made. How it's made up. And I'm going to do that. I'm going to look at the structure and the atomic structure of hydrogen because it's the simplest of our atomic materials. It, if we think of our protons and there are protons in these diagrams are this symbol. Our neutrons, neutrons and protons are about the same weight. About the same mass. But protons have a positive charge and neutrons have no charge. And electrons are much smaller, a two thousandth of the size of a proton or a neutron and are negatively charged. And here we have in our three diagrams we have three types of hydrogen and you'll notice what makes it hydrogen, is that we have just one proton in the center and one electron. The electron is not as important because that could be pulled away from the atom and makes the atom charged sometimes. Turns it into what we call an ion. But for the moment let's look at the center of the nucleus, here we have one proton, one proton, one proton. But in this type of hydrogen it still got one proton but it's getting a neutron as well. And here we have two neutrons, in fact this doesn't work. This is radioactive, this nucleus breaks up so it doesn't exist for very long. Now therefore, we have three different types of hydrogen and chemically they are identical. You can have water made of hydrogen one, water made of hydrogen two, water made of hydrogen three and you can also have water made partly of hydrogen one and hydrogen two. So these all exist. So chemically they are the same, they behave in the same way, they react in the same way. But physically they are different and hydrogen is interesting because hydrogen two is twice as heavy as hydrogen one. And from hydrogen two, we can get heavy water and we'll call it heavy water because it's H2O, this also H2O but this is just ordinary water. And in fact this is about ten percent heavier for the same amount of water. So it's significantly heavier. It's only in the case of hydrogen that this occurs. So hydrogen, what is it like, well it's a gas. We can't see it. But we know it burns, it burns very well. It explodes and when it burns it produces water because it combines with oxygen to produce H2O which is water. And this is interesting because both of these materials, hydrogen and oxygen are very reactive materials and yet they produce something which to us is not reactive at all, essential to life. So that's a little bit about hydrogen.