 Good morning. I'm standing here in the Museum of the College of Earth and Mineral Sciences at Penn State University. In 2013 there have been a number of very severe weather events in the United States such as the large tornadoes that hit the south-central part of the country early this spring. Meteorologists and climatologists still don't fully understand whether climate change will lead to an increase and an intensification of these large events. The reason for this is Earth's climate is extremely complex. And in this module you're going to learn about this complexity. Please don't be fazed by all of the equations and the relationships. What we really want you to come away with is a strong grasp of the physical relationships between the different parameters. Energy, heat, weather and climate. So without further ado I'm going to show you how a tornado works and then you can get busy. We need moisture at the bottom of the tank and then we need an updraft provided by fronts in the Earth's weather systems. We need some rotation and bingo we have a tornado.