Structures are all around us. Everywhere we go; everywhere we look. They come in all shapes and sizes. Some are made by people while others are natural. Structures provide us with shelter and protection. All structures have force acting on them. In this video, Professor Peter Plankton and Professor Tess Tube examine these forces. They specifically look at the impact of earthquakes and tornadoes. Footage from the recent earthquake and tsunami in Japan shows the devastating impact of these natural forces. Students will learn the difference between internal forces and external forces (live load vs. dead load); the various types of forces including compression and tension; materials and their properties; and the environmental impact of these events.