Metric-Asaurus: Conceptualizing Scale Using Dinosaur Models

Article excerpt

Humans have a fascination with dinosaurs that transcends age, but middle school students, especially, are engaged by imagining the enormous teeth of the ferocious meat-eating Tyrannosaurus rex grasping its prey, or the thundering of the gigantic feet of a herd of Apatosaurus as they move across the land. Another aspect of dinosaurs that captures the interest of students is their enormous size. 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.

Following the 5E learning cycle, students use dinosaur scale models and casts of dinosaur footprints to plan and conduct an investigation to determine the real-life size of a dinosaur. In the Engagement phase, after a review of the Mesozoic tropical climate and plant life, students are introduced to fossils in their area or at a location where dinosaur fossils are readily found. In the Exploration I phase, students collect measurements of museum-quality scaled dinosaur models, and in the Exploration II phase, students measure dinosaur footprints (tracks). Then, using the measurements from the models in Exploration I and the footprint measurements from Exploration II, students predict and then determine how to set up a proportional relationship to calculate the length of the dinosaur. The Evaluation phase of the lesson assesses students' understanding of ratio and proportion using scale models of animals such as horses or inanimate objects such as trains.


Dinosaur fossils can be found throughout the United States, and while ideally students will study local geologic formations along which dinosaurs roamed, this is not a requirement of the activity. Students can explore geologic formations -with dinosaur fossils using the internet. Teachers may choose to have students work with students from a school in an area that does have geologic formations containing dinosaur fossils--students can share information over the internet, compare results, and discuss problems and solutions. For dinosaur-related websites, see Resources. This lesson is illustrated using dinosaur fossils found in Texas, in particular those found in Dinosaur Valley State Park.


Color-coded regional geologic highway maps (see Resources) that show Mesozoic geologic formations where dinosaur fossils are typically found can help students visualize where sedimentary rock formations developed during the time dinosaurs roamed the area. This is an opportunity to review from previous lessons the sedimentary rock types and how they were formed. For example, the Glen Rose limestone formation in Texas formed through deposition from shallow seas during the Cretaceous period (Spearing 1991). The muddy regions surrounding the seas made a prime area for dinosaur tracks to be laid down and preserved.


To engage students, the teacher relates the following true story of the discovery and preservation of a set of dinosaur tracks called a trackway. Students are particularly amused by the idea that a truant schoolboy made the discovery of three-toed dinosaur tracks in 1908 in what is now Dinosaur Valley State Park in Texas (Farlow 1993). Eventually, Ellis Shuler of Southern Methodist University published three papers on the tracks. This, in turn, piqued the attention of R.T. Bird in 1938, a fossil collector for the American Museum of Natural History in New York. Subsequently, Bird's boss, Barnum Brown, one of the most successful dinosaur hunters, decided to create an exhibit of dinosaur footprints at the museum. …