Hook Students by showing them a picture of a T. Rex and asking students to explain what type of food they think the dinosaur ate, based on skeletal observations. This is also a great link that discusses how the T. Rex dinosaur skeleton has changed over time.
I want my students to realize that scientific ideas are always changing, based on the evidence presented and available at that time. This question segues nicely into the focus of today's lesson -- how can we observe and infer information about dinosaurs from their fossils?
After you take a poll by asking students what they think the T. Rex consumed, explain that scientists are in disagreement about the topic and give some insights:
1) The small arms suggest that it wasn't a hunter, based on what we know about predators in nature today.
2) Some say that they ate smaller, immature dinosaurs like animals do today and that small arms were used to help it up if it fell over.
3) Share more idea from your own research.
Explain that they are going to investigate fossilized bones of an unknown dinosaur that were recently collected in an area and use them to reconstruct the skeleton. After researching dinosaur fossils on Day 2, they will alter their initial skeletal structures and support their changes with evidence (SP8). They will then try to create a drawing of how they think the dinosaur appeared and maybe discuss what they think that it ate.
It's important to give students time in class to develop their science and engineering practices. The video below demonstrates students developing their argumentation skills (NGSS SP7 - Engaging in Argument from Evidence - specifically, "Respectfully provide and receive critiques about one’s explanations, procedures, models, and questions by citing relevant evidence and posing and responding to questions that elicit pertinent elaboration and detail.").
I encourage students to disagree with their peers. The only caveat is that they must back their inferences with appropriate and logical evidence. Scientists disagree all the time--encourage this practice in your class with your students. Sometimes coming to a consensus is perfectly acceptable, as students will have to do when they create their initial model of how they think the skeletal structure of their dinosaur should appear.
Phase one of the activity is having students sit with their groups to record observations about each bone, or similar bones, in their notebooks. You should distribute these worksheets to your students.
NOTE: Do not give out the pictures of the actual skeleton or how the dinosaur may have looked.
In phase two of the activity, students cut out their bones and reconstruct the skeleton based on their observations and inferences. They then glue the skeleton to a piece of paper, as depicted in this image.
You should reserve time for students to take 30 seconds per group to share their initial models of their skeletons with the entire class.
Leave time for clean up and collect skeletons for use during tomorrow's class.