Computing as a Central Computing as a Central Theme in Introductory Theme in Introductory PhysicsPhysics

Martin S. MasonMartin S. Mason

Mt. San Antonio CollegeMt. San Antonio College

June 2012June 2012

What is computational What is computational modeling?modeling? Using the outputs of a computer Using the outputs of a computer

system to describe or predict the system to describe or predict the behavior of a physical system.behavior of a physical system.

Why Computational Why Computational Modeling?Modeling? Tackle interesting problems that can’t Tackle interesting problems that can’t

be ‘solved’ analytically with freshman be ‘solved’ analytically with freshman physics, but can be approximated.physics, but can be approximated.

This is no right answer, just a series of This is no right answer, just a series of more accurate approximations. more accurate approximations.

A large part of what modern Scientists A large part of what modern Scientists and Engineers actually do!and Engineers actually do!

Students need Students need Computational SkillsComputational Skills

A New direction for A New direction for Physics LaboratoriesPhysics Laboratories What best describes your laboratory?What best describes your laboratory?

A.A. Separate from Lecture with a different instructor / TASeparate from Lecture with a different instructor / TA

B.B. Separate from Lecture with the same instructorSeparate from Lecture with the same instructor

C.C. Integrated with Lecture (Studio or Workshop format)Integrated with Lecture (Studio or Workshop format)

D.D. Block ScheduleBlock Schedule

E.E. No Lab definedNo Lab defined

How often is lab offered per week?How often is lab offered per week?A.A. 4 or more times4 or more times

B.B. 3 times3 times

C.C. TwiceTwice

D.D. OnceOnce

What should we do in What should we do in Laboratory?Laboratory?

Laboratory activities must be designed so that students may acquire skill and Laboratory activities must be designed so that students may acquire skill and confidence in: confidence in: – Measurement of physical quantities with appropriate accuracy Measurement of physical quantities with appropriate accuracy – Recognition of factors that could affect the reliability of their measurements Recognition of factors that could affect the reliability of their measurements – Manipulations of materials, apparatus, tools, and measuring instruments Manipulations of materials, apparatus, tools, and measuring instruments – Clear descriptions of their observations and measurements Clear descriptions of their observations and measurements – Representation of information in appropriate verbal, pictorial, graphical, and Representation of information in appropriate verbal, pictorial, graphical, and

mathematical terms mathematical terms – Inference and reasoning from their observations Inference and reasoning from their observations – Ability to rationally defend their conclusions and predictions Ability to rationally defend their conclusions and predictions – Effective and valued participation with their peers and their teacher in a Effective and valued participation with their peers and their teacher in a

cooperative intellectual enterprise cooperative intellectual enterprise – Articulate reporting of observations, conclusions, and predictions in formats Articulate reporting of observations, conclusions, and predictions in formats

ranging from ranging from – Informal discussion to a formal laboratory report Informal discussion to a formal laboratory report – Ability to recognize those questions that can be investigated through Ability to recognize those questions that can be investigated through

experiment and to plan, carry out, evaluate, and report on such experiments. experiment and to plan, carry out, evaluate, and report on such experiments.

What is Vpython?What is Vpython?

a free, open-source, multi-platform, a free, open-source, multi-platform, 3D programming environment 3D programming environment especially suitable for use by especially suitable for use by students in introductory physics students in introductory physics courses (including novice courses (including novice programmers). programmers).

Written by David Scherer forWritten by David Scherer for Ruth Ruth Chabay and Bruce Sherwood’s Chabay and Bruce Sherwood’s Matter and Interactions Matter and Interactions coursecourse

Computational Computational Modeling in the labModeling in the lab What do we do?What do we do?

– Extend hands on experiments with Extend hands on experiments with modelsmodels

– Create visualizations that help with Create visualizations that help with conceptual understandingconceptual understanding

– Develop transferable programming and Develop transferable programming and visualization skillsvisualization skills

What don’t we do:What don’t we do:– Run simulations that someone else wroteRun simulations that someone else wrote

Why Do Projects?Why Do Projects?

Students as ScientistsStudents as Scientists Treat more detailed problemsTreat more detailed problems Give sense of connection between Give sense of connection between

physics topicsphysics topics How and Why physics is usefulHow and Why physics is useful It’s Fun!It’s Fun!

ProjectsProjects

Three 5 week projects.Three 5 week projects. Six hours in class and 20-30 hours Six hours in class and 20-30 hours

outside of class.outside of class. Project is designed to require course Project is designed to require course

material from that five week period material from that five week period and before.and before.

Projects change every semester.Projects change every semester. Project is presented as a formal Project is presented as a formal

powerpoint presentation.powerpoint presentation.

Types of ProjectsTypes of Projects

Create a computational model that Create a computational model that predicts the behavior of a physical system.predicts the behavior of a physical system.

Create a computational model that Create a computational model that investigates something that can’t be investigates something that can’t be modeled physically.modeled physically.

An open ended problem chosen by the An open ended problem chosen by the student, Compare the behavior of a student, Compare the behavior of a physical system and the behavior of a physical system and the behavior of a computational model with theoretical computational model with theoretical calculations.calculations.

ExampleExample

Model the behavior of a Model the behavior of a foam rocket launched foam rocket launched from an elastic launcher.from an elastic launcher.

Compare the results of Compare the results of your model to the actual your model to the actual trajectory determine trajectory determine from video analysis.from video analysis.

Competition.Competition.

ExampleExample

Create a system of three lunar orbiting Create a system of three lunar orbiting communication satellites that always communication satellites that always provide a link from the north pole of provide a link from the north pole of the moon to the earth. the moon to the earth.

Include the gravitational effects of Include the gravitational effects of both the moon and earth on the both the moon and earth on the satellites.satellites.

Show that your system is stable for 10 Show that your system is stable for 10 years.years.

Final ProjectFinal Project

A mass is placed on a low friction A mass is placed on a low friction cart attached to a spring. At what cart attached to a spring. At what amplitude will the mass on the amplitude will the mass on the cart begin to slip?cart begin to slip?

Video of SystemVideo of System Computational modelComputational model Textbook solution makes many Textbook solution makes many

simplifying assumptionssimplifying assumptions

Outcomes:Outcomes:

More students transition into summer More students transition into summer REU/Research programs.REU/Research programs.

Anecdotal reports are positive about Anecdotal reports are positive about the utility of projects after transfer.the utility of projects after transfer.

Difficult to measure impact on Difficult to measure impact on traditional assessment.traditional assessment.

Student retention was lower for first Student retention was lower for first three semester after the projects were three semester after the projects were implemented, but has climbed back implemented, but has climbed back up.up.

Project Grades vs. Project Grades vs. Exam GradesExam Grades Projects measure Projects measure

different skills different skills then exams. then exams.

Students who do Students who do well on exams do well on exams do not always do not always do well on projects well on projects and vice versa.and vice versa.

Project Rank Exam Rank

1 4

2 2

3 3

4 6

5 20

6 7

7 14

8 1

9 18

10 12

11 16

12 11

13 8

14 15

15 17

16 9

17 10

18 5

19 13

20 19