For middle school students who have seen only pictures of dinosaurs in books, in the movies, or on the internet, trying to comprehend the size of these gargantuan animals can be difficult. This lesson provides a way for students to visualize changing scale through studying extinct organisms and to gain a deeper understanding of the history of the Earth. Additionally, the lesson provides an opportunity for middle school students to use mathematics in understanding how dimensions change as scale changes. (Contains 14 online resources and 6 figures.)