As students tour the two Dinosaur Halls, they will investigate the following questions:

• What are bone and trace fossils and what do they tell us about dinosaurs?
• What do certain features, such as teeth, crests, or claws, tell us about dinosaur behavior?
• What caused dinosaur extinction?
• Are all dinosaurs extinct?

Prepare students for their visit by conducting one or more of the following activities.

Set up a Classroom Resource Center
Encourage students to bring in books, models, and posters related to dinosaurs, geology, and paleontology. Set up a classroom resource center where students can explore and read about dinosaurs and paleontology on their own.

Visit the American Museum of Natural History's Web Site
Encourage students to join paleontologists from the Museum as they scour the scorching sands of the Gobi Desert in search of fossils. Visit the Museum's Web site at: www.amnh.org.

Introduce Dinosaurs
Begin by holding a class discussion about dinosaurs. Call on students to share what they know, as well as the questions they have about dinosaurs. Create a K-W-L Chart (What we Know, What we Want to Know, What we Learned) and continually update it as students answer the questions they have and generate new ones.

Define Dinosaur
Write "What is a dinosaur?" on the chalkboard. Call on volunteers to describe some features of dinosaurs that set them apart from other animals. Write their suggestions on the board. Have students work in small groups to further explore this question, using books and Internet resources. Allow groups 15 - 20 minutes to find information about dinosaurs. Have groups report their findings to the rest of the class. Write responses on the chalkboard and use them to create a definition of dinosaurs.

Identify Different Kinds of Fossils
Explain to students that fossils are the remains of dinosaurs or other ancient animals. Bone fossils come from the animal itself and include bones, claws, and teeth. Trace fossils are what the dinosaur left behind. They can be skin impressions, footprints, and nests with eggs. They provide clues to how dinosaurs might have behaved. Display the pictures of the bone and trace fossils found on Insert 3. Elicit from students that by carefully studying fossils, scientists learn about how these animals may have looked and behaved. Ask students what information scientists might glean from a tooth, a bone, or a set of footprints.

Have students create their own fossils following these directions:

Materials
Chicken bones (with all the meat boiled off), shells, feet (from dinosaur or animal models), frozen-food trays, and modeling clay.

Procedure

• Fill trays with 1/2 - 1 inch of clay.
• Arrange bones in tray and gently press down. Use shells and feet to make impressions. Feet may be used to make a trackway (see At the Museum insert for description of trackways). Remove objects when finished.
• Have students trade trays with one another. Ask them to examine the fossils and draw three conclusions about the animal that made the impression. Allow time for them to share their findings.

Explore the Functions of Teeth
Teeth hold important clues about what an animal ate and even how it may have behaved. Have students examine the features and functions of teeth following these directions:

Materials
For each group you will need: a small mirror, lettuce leaves, two small flat stones, staple remover, and cotton balls.

Procedure

• Have students work in small groups. Distribute materials to each group.
• Display the staple remover. Tell students it represents the sharp teeth of a meat eater. Using the cotton balls, model how a meat eater might rip apart meat. Point out the rocks and explain that they represent the flat, grinding teeth of a plant eater. Using the lettuce, model how a plant eater might grind up vegetation.
• Have students experiment with the materials to determine which set of teeth worked best for each food.
• Then, using the mirrors, have students examine their own teeth. Have them identify and sketch the three different kinds of teeth they have (incisors, canines, and molars). Ask them to hypothesize how each of the three kinds of teeth are used.
• Have groups discuss their findings. Point out that teeth provide the best clues to what dinosaurs ate.

Many plant-eating dinosaurs had hundreds of teeth that grew throughout their lifetime.

Some dinosaurs, like Apatosaurus, had long, peg-like teeth. They used their teeth to strip leaves off tree branches. Tyrannosaurus had sharp, serrated, knife-like teeth. It used them to rip meat off its prey. Triceratops had a set of flat teeth with sharp ridges. It used the teeth to slice up plants. Anatotitan had sets of grinding teeth, which were used to grind up plants. Explain that students will learn more about dinosaur teeth when they visit the Dinosaur Halls at the American Museum of Natural History.