Models and Modelingin the High SchoolPhysics Classroom

Larry DukerichModeling Instruction ProgramArizona State University Dobson HS - Mesa, AZ

The Problem with Traditional Instruction

• It presumes two kinds of knowledge: facts and knowhow.• Facts and ideas are things that can be

packaged into words and distributed to students.

• Knowhow can be packaged as rules or procedures.

• We come to understand the structure and behavior of real objects only by constructing models.

“Teaching by Telling” is Ineffective

• Students usually miss the point of what we tell them.

• Key words or concepts do not elicit the same “schema” for students as they do for us.

• Watching the teacher solve problems does not improve student problem-solving skills.

Memorization vs Understanding

• What does it mean when students can readily solve the quantitative problem at left, yet not answer the conceptual question at right?

4

2

68V

PQ

AB

CS

For the circuit above, determine the current in the 4 resistor

and the potential difference between P and Q.

Bulbs A, B and C are identical. What happens to the brightness of bulbs A and B when switch S is closed?

• Construct and use scientific models to describe, to explain, to predict and to control physical phenomena.

• Model physical objects and processes using diagrammatic, graphical and algebraic representations.

• Small set of basic models as the content core of physics.

• Evaluate scientific models through comparison with empirical data.

• Modeling as the procedural core of scientific knowledge.

Instructional Objectives

Why modeling?!• To make students’ classroom experience closer to

the scientific practice of physicists.• To make the coherence of scientific knowledge

more evident to students by making it more explicit.

• Construction and testing of math models is a central activity of research physicists.

• Models and Systems are explicitly recognized as major unifying ideas for all the sciences by the AAAS Project 2061 for the reform of US science education.

• Robert Karplus made systems and models central to the SCIS elementary school science curriculum.

Models vs Problems

• The problem with problem-solving• Students come to see problems and their answers

as the units of knowledge.• Students fail to see common elements in novel

problems.

“But we never did a problem like this!”

• Models as basic units of knowledge• A few basic models are used again and again with

only minor modifications.• Students identify or create a model and make

inferences from the model to produce a solution.

What Do We Mean by Model?

• with explicit statements of the relationships between these representations

Symbolic Representations

Physical System

Mental Model

Verbal

Algebraic

Diagrammatic

Graphical

Multiple Representations

• with explicit statements describing relationships

How to Teach it?

constructivist vs transmissionistcooperative inquiry vs lecture/demonstration

student-centered vs teacher-centered

active engagement vs passive reception

student activity vs teacher demonstration

student articulation vs teacher presentation

lab-based vs textbook-based

I - Model Development

•Students in cooperative groups• design and perform experiments.• use computers to collect and

analyze data.• formulate functional relationship

between variables.• evaluate “fit” to data.

I - Model Development

•Post-lab analysis• whiteboard presentation of student

findings• multiple representations» verbal» diagrammatic» graphical» algebraic

• justification of conclusions

Preparing Whiteboard

Making Presentation

II - Model Deployment

• In post-lab extension, the instructor• brings closure to the experiment.• fleshes out details of the model, relating

common features of various representations.• helps students to abstract the model from

the context in which it was developed.

II - Model Deployment

• In deployment activities, students

• articulate their understanding in oral presentations.

• are guided by instructor's questions:

» Why did you do that?» How do you know that?

• learn to apply model to variety of related situations.» identify system composition

» accurately represent its structure

II - Model Deployment

•Objectives:• to improve the quality of scientific discourse.• move toward progressive deepening of

student understanding of models and modeling with each pass through the modeling cycle.

• get students to see models everywhere!

•Ultimate Objective:• autonomous scientific thinkers fluent in

all aspects of conceptual and mathematical modeling.