Activity Five: An Explanation, and a Dessert
Activity Overview
Modeling atoms and molecules can help explain the macroscopic of a substance.In this activity students revisit their models and explanations of the changes of state, evaluate their ideas, and discuss them based on new understanding they gained from this module.
Learning Objectives
Students will: d
Discuss explanation and models using particulate theory as it relates to macroscopic properties and observations. [???}
Conceptual Prologue
Macro-Micro Connection
Throughout this module students have observed and described several examples of substances and their different phases of matter. However, these are just a few of the many examples students encounter. One enjoyable example includes making ice cream. As a conclusion to this module you may want to have students come up with an explanation for what happens when you make ice cream. Then perhaps have the kids make it.Science Concepts
For scientists, a model is not a true description of a system. Instead they think of it as a set of rules and assumptions that when put together will help them think about and perhaps explain some aspect of reality. As a result of this idea, scientists understand that models are limited in scope. The models that are created cannot represent everything; the real world is too complex. Scientists therefore use models as a tool and analyze them for their strengths in representing phenomenon as well as their weaknesses.Naïve Conceptions
Students typically think of models as little replicas or pictures of reality. (Bent, 1984)
Models are truth and therefore don't need to be evaluated. (Grosslight, Unger, Jay, 1991)
Activity Design and ExecutionMajor Science Concepts: Phase change, inter-atomic forces, matter is made of atoms/molecules
Assumed Prior knowledge:
Ability to recognize when a bunch of atoms/molecules represents a solid, a liquid, or gas.
Understand that molecules are in continuous motion.
Time: 50 minute class session.
Materials: None
Advance Preparation: Make copies of the student posttest for use in this session.Investigation Question: What is the difference between a solid, a liquid, and a gas? How does the nature of the model help you understand these differences?
Procedure
1. Begin this activity by reviewing and discussing student responses to the Modeling Phase Changes Worksheet.
2. Remind students of the Volcano story they read. Ask them the following question: "In this story what substances are changing and how are they changing? What do you think is happening to the molecules of each the substances?" Discuss what is happening to the lava and the water in the story.
3. Distribute and administer the post-test.