For this video, we're going to go over the different classifications of structures, so when we're investigating structures, not only are we going to be thinking about the form and the function but also how to classify it. So the first classification is solid. Now, a solid structure appears to be a solid piece of construction. The example that I'm going to use is a dam. If we think about the Hoover Dam, it seems to be a solid piece, not a combination of parts making up that structure. Frame, a frame structure is one that has several parts working together or a skeleton parts put together that support each other. I'm using an example: we see them in downtown Toronto, those buildings that are made it appears like they're made just of windows so they would have a frame and then they would have all of these windows, so all of these parts make up a structure and they all have to work together to support each other, there isn't one part in this structure that's supporting all of it so if all the parts don't work together the structure could have damaged or could not hold its load or could simply fall down. The next classification is a shell structure. So this is a structure that has a curve to it and has a sort of a hollowed part to it, we can think of an egg if you think about a bicycle helmet, these are considered shell structures. And then there is combination structures and the best example is a human body. Yes, that is a human body. If you think about our skull it is a shell structure, it has a curved appearance and it's hollowed on the inside. For great support the bone in our leg, the femur could be considered a solid structure because it appears like it's just one solid piece of bone and the entire skeleton together is a skeleton or a frame structure. So those are the classifications of structures.