Related Lessons

Hollywood Dinosaurs

Science is characterized by the testing, improving, and occasional discarding of theories in an attempt to formulate increasingly accurate accounts for how the world works. Scientists may come up with different hypotheses or theories; however, all these arguments must conform to the principles of logical reasoning. Thus, despite their different opinions, all scientists must test the validity of their arguments by applying certain criteria of inference, demonstration, and common sense.

Scientists may also disagree about the value of a particular piece of evidence, or about the assumptions made in studying the evidence, and therefore disagree about what conclusions are justified. However, professional scientists all tend to agree about the principles of logical reasoning that connect evidence and assumptions with conclusions.

In this lesson, students examine characteristics of the scientific process in the study of dinosaurs. Dinosaurs hold a place of awe and wonder for humans; the success of the Jurassic Park movies and books is testament to the fact that these extinct animals fascinate us. However, entertainment has a tendency to misrepresent scientific knowledge and blur the lines between scientific fact and imagination. For most students, dinosaurs are the large, scary animals in the movies. This lesson allows students to differentiate between fact, theory, and speculation as they relate to dinosaurs. Students also make their own theories using relevant evidence, thereby practicing the use of logical reasoning. Finally, students examine recent evidence that challenges the prevailing theory that all dinosaurs were cold-blooded.

The notion that scientific knowledge is always subject to modification can be difficult for some students to grasp. It seems to oppose the certainty and truth accorded to science in textbooks and popular culture. Some research indicates that it is difficult for middle-school students to understand the development of scientific knowledge through the interaction of theory and observation. However, the lack of long-term teaching interventions to investigate this issue makes it difficult to conclude that students can or cannot gain that understanding at this grade level. Research also shows that students of all ages find it difficult to distinguish between a theory and the evidence for it, or between the description of evidence and interpretation of evidence. It has been suggested, though, that students can understand the distinction between theory and evidence, after adequate instruction, as early as middle school. (Benchmarks for Science Literacy, p. 332.)

This lesson provides students the opportunity to differentiate between facts and theory in the context of an interesting subject matter. Before beginning this lesson, students should have a basic understanding of what a fossil is. Time may need to be spent with students to clarify what fossils are, how they are formed, how they are found, and the significance of the fossil record in our understanding of the world. Students can learn these concepts through a Science NetLinks two-lesson series for grades 3-5. Fossils and Dinosaurs provides students the opportunity to learn from fossils, and in doing so, realize the difference between fact and theory. The second lesson, Dinosaur Fossils-Uncovering the Facts allows students to recognize the kind of information that can be accumulated from studying dinosaur fossils, as well as understand that some fossil facts are made based on comparisons with living organisms.

Another good activity that students can do before beginning this lesson can be found at DiscoverySchool.com. This lesson, entitled Dinosaur Detectives, introduces students to the work performed by paleontologists over time in terms of both finding fossils and using the fossil record to come up with scientifically accurate theories.


Planning Ahead

Materials:

• Dino-Facts student sheet (You should cut out the facts and place them in an envelope ahead of time.)
• Researching Dinosaurs student sheet
• Hollywood Dinosaurs student E-Sheet

• How many of you have seen Jurassic Park I, II, or III?
• How many different types of dinosaurs do you think they showed in the Jurassic Park movies?
• Describe some characteristics of dinosaurs as depicted in the movies.

Ask students:

• Do you think that movies depict dinosaurs as they really existed?
• Why or why not?

Ask students:

• Were humans alive during the existence of dinosaurs?
• If humans were not alive to observe dinosaurs, how do we know what they looked and acted like?

Ask students:

• What is a theory? (A hypothesis that is used to explain something. A theory is always based on a set of facts.)
• For example, if a student comes to class carrying gifts, holding balloons, and smiling a lot, what would be a theory to explain his/her behavior? (It's his/her birthday.)
• What is the evidence for the birthday theory? (The gifts, balloons, and smiling.)
• Could there be other theories that fit the evidence? (Yes.)
• What are some other plausible theories for the student's behavior? (He/she might be surprising another student on his/her birthday or any other type of special occasion. The student might be graduating.)

Have students learn about Sue, the T rex, by visiting The Field Museum website. Students can access the URL directly by using the E-Sheet, Hollywood Dinosaurs. This E-Sheet provides students with the links and instructions on what to read, as well as questions to answer. If students' online time is limited, you may want to print, copy, and distribute the E-Sheet and the articles referenced.

After students have completed the assignment, discuss the following:

• Describe the difference between a theory and speculation.
• Describe the theories about Sue discussed in the article. What evidence are the theories based on? (The theories are based on the fossil evidence.)
• The article told us that there is no evidence for the color of dinosaur skin. Why do you think that movies show dinosaurs as being brown or green or sometimes very colorful? (While there is no evidence for the color of dinosaur skin, scientists can make comparisons to living reptiles today. Most reptiles are brown or green in color. Based on this speculation, dinosaurs are depicted as having skin of this color.)
• What is Sue's gender? (Students may or may not have read this section of the article. Sue's sex is unknown—there is no evidence either way to prove that Sue was a male or female. She is named after her discoverer, Sue Hendrickson.)

These three dinosaurs lived roughly 80 million years ago in the mountains of Montana (show students Montana on a United States map). The environment at that time included volcanoes and a few mountains to the west (not the Rocky Mountains as they were in the process of uplifting) and to the east, a warm interior seaway that divided North America from north to south. There is good fossil evidence to show that all three laid eggs in nests. The nesting sites included two islands surrounded by a shallow lake.

Divide students into groups. Provide each group with a procedure list and an envelope of the various dinosaur facts from the student sheet, Dino-Facts. Review the procedures with students and then allow students sufficient group time to develop theories. Provide guidance only when necessary. If students have multiple theories for one set of facts, encourage them to write down all the theories and present them to the class.

Note: These sets of facts are adapted from a unit on dinosaur behavior by the University of California, Berkeley, Museum of Paleontology. This particular set of facts is based upon work done by Jack Horner and other associates of The Museum of the Rockies in Bozeman, Montana. The data has been used in order to theorize about the behavior of dinosaurs in that area.

If students need more guidance developing a theory from a set of Dino-Facts, use the following example:

Fact #1 states that Maiasauras probably ate nearly 200 lbs. of vegetation each day, and Fact #11 states that they have been found in herds up to 10,000 in number. A group discussion around these two facts might result in a theory such as: The Maiasauras must have migrated because they would need to find new food sources.

After sufficient time has been allowed for each group to develop theories of dinosaur behavior, ask a volunteer from each group to state the group's theories and the supporting evidence. As groups state their theories, ask the class the following:

• Do you believe this theory is plausible or makes sense based on the evidence?
• Are there alternate theories of dinosaur behavior based on the facts?

• Did you find developing theories to be difficult or easy?
• What things made developing theories difficult?
• What things made developing theories easy?
• If you had only half of these Dino-Facts, would developing theories be easier or more difficult? Why?
• Sometimes, theories change based on new evidence. Why do you think that happens?

Tell students that they will read an article about some new fossil evidence found recently in the United States. This new evidence challenges the theory that dinosaurs were all cold-blooded animals.

Again, allow students to access the student E-Sheet, Hollywood Dinosaurs, or provide each student with a printed copy of the E-Sheet and copies of the online articles used in this section. Students will answer questions based on the reading. This activity can be done as homework or in the school computer lab.

After students have completed the reading and questions, ask the following:

• What is the prevailing theory about dinosaurs being warm or cold blooded?
• How does Willo provide evidence to challenge the theory that all dinosaurs are cold blooded? (The preserved heart found inside Willo is much like that of other warm-blooded animals.)
• Do you think scientists now have to reconsider their theories that all dinosaurs were cold blooded? (Answers may vary.)
• If a scientist says that T. Rex is warm-blooded, is that a fact, theory, or speculation? (Speculation)
• Why is this a speculation and not a fact?
• Why is this a speculation and not a theory?

Provide each student pair with the student sheet, Researching Hollywood Dinosaurs. Tell students that they will use the websites listed on the activity sheet to research dinosaurs. They must find a minimum of five characteristics about dinosaurs found in movies and/or books and state whether these characteristics are based on evidence or are just speculation. Again, the links for the student sheet are accessible to students through the E-Sheet, Hollywood Dinosaurs.

After students have completed the research, ask them:

• Which characteristics of dinosaurs are based on facts?
• Which characteristics of dinosaurs are speculations?
• Why is evidence important in the study of dinosaurs?
• Why do you think there is so much speculation about the way dinosaurs looked and behaved?

Ask students:

• Are there any "facts" that should be changed to "fiction?"
• Are there any "fictions" that should be changed to "fact?"

• Understand that discoveries about dinosaurs have a long history and that each paleontologist adds his or her work to a body of fossil evidence used to support theories about dinosaurs.
• Find out that paleontologists often support one theory over another until additional fossil evidence either confirms or disproves the theory.
• Understand that paleontologists can learn more about dinosaurs through new scientific techniques.

Created :10/20/2001