Physics-Chemistry-Biology:A Logical and Effective Sequence

Rex P. Rice

Clayton High School

Clayton, Missouri

Physics First: Not a New Idea

• Physics and the High School Sophomore (Hamilton, TPT, 1970)

• Physics in the Tenth Grade (Sousanis, TPT, 1971)

• The Illogic of Teaching Bio Before Chem and Physics (Palombi, TPT, 1971)

• Take Physics to Ninth Graders With Budget Savers (TPT, 1974)

• High School Physics Should be Taught Before Chemistry and Biology (Haber-Schaim, TPT, 1984)

• Physics Before Chemistry (Bolton,TPT, 1987)

• A Case for a Better High School Science Sequence in the 21st Century (Myers, TPT, 1987)

• Freshman Physics (Hickman, The Science Teacher, 1990)

Haber-Schaim Article

• Average of 23 Chemistry Prerequisites in Biology Textbooks

• Average of 31 Physics Prerequisites in Chemistry Textbooks

• No Biology Prerequisites in Physics Textbooks

• Average of 2 Chemistry Prerequisites in Physics Textbooks

Committee of TenNational Education Association

1892Recommendations Regarding Physics:

• The study of chemistry should precede the study of physics.

• The study of physics should be pursued the last year of high school.

Reasons for Traditional Biology-Chemistry-PhysicsSequence at Turn of Century

Start with biology because:1. Relied mostly on memorization2. Required almost no mathematics

Reasons for Traditional Biology-Chemistry-PhysicsSequence at Turn of Century

Follow with chemistry because:1. Relied mostly on memorization and

detailed experimental procedures2. Required only modest amounts of

mathematics

Reasons for Traditional Biology-Chemistry-PhysicsSequence at Turn of Century

Make physics last because:1. Required greater mathematical

fluency2. Relied heavily on problem solving,

analysis, and critical thinking

Advantages of TeachingPhysics to Freshmen

(Hickman, 1990)• Algebra is still fresh in students minds

• Freshmen are enthusiastic and motivated

• Most students who start with physics complete the science sequence

• Increased interest in math courses

• Enrollment in senior physics course increases

• AP Biology can be the first biology course if physics and chemistry have been studied

Disadvantages of TeachingPhysics to Freshmen

(Hickman, 1990)• Shortage of qualified physics teachers• Opposition to change from “proven” sequence by parents,

teachers, administrators, school boards• Freshmen are more active, noisier, less coordinated• Measurement and estimation skills are not good• Trigonometry has not been studied• Problems of transition of from middle school to high school

level course• Lack of problem solving and test taking skills

Clayton High SchoolClayton, Missouri

• One high school in district

• About 800 students in grades 9-12

• Fairly affluent suburban school district

• About 20% of students are African American students from neighboring city of Saint Louis

Physics First at Clayton High School

• Quantitative Science in place since early ‘60s

• Other course thought of as “dummy course”

• Best students already followed the Physics-Chemistry-Biology sequence

• Algebra taken by all students in Eighth Grade

Physics First at Clayton High School

• Presented “Inverted Sequence” idea to curriculum committee in Spring of 1991

• Full inversion considered too radical a change• Two courses, Honors Freshman Physics and

Freshman Physics, proposed• School Board approved change for the start of

1991-92 school year

Freshman Physics: ‘91/92Text: Conceptual Physics-Hewitt• Light• Waves and Sound• Kinematics• Newton’s Laws• Work, Energy, Power• Circular Motion and Gravitation• Properties of Matter• Heat• Electricity and Magnetism

Honors Freshman Physics: ‘91/’92Based on “Quantitative Science”

• Geometric Optics1. Plane Mirrors2. Pinholes3. Curved Mirrors4. Refraction5. Lenses

Honors Freshman Physics: ‘91/92Based on “Quantitative Science”

• Mechanics1. Uniform Motion2. Uniform Acceleration3. Newton’s Laws4. Work, Power, Energy

Honors Freshman Physics: ‘91/92Based on “Quantitative Science”

• Electricity and Magnetism1. Electrostatics2. D.C. Circuits3. Magnetism

Transition toPhysics-Chemistry-Biology

• Chemistry teachers initially resisted moving chemistry to 10th grade

• Initial resistance to “inversion” faded with departmental discussion

• Complete inversion led by biology teachers• Period of one year where chemistry was offered to

sophomores and juniors• “Inversion” completed by 1995/96 school year

Reactions /Results• Chemistry teachers found that sophomores

did fine with chemistry• Biology teachers were elated with their

ability to upgrade the biology program• A.P. Physics “worked” as a one-year course

since students entered with a physics background.

• More students took two or more A.P. science courses since many were able to take A.P. Biology as a first-year course

Shift to Modeling Methods

• In summer, 1995 I attended the first of three years of training in Modeling Methods in High School Physics at Arizona State University

• In 1995-96 I started using Modeling in all of my physics courses, including freshman physics

• Since then, four of five physics teachers have been trained in Modeling and are using it in Freshman Physics.

How Has Modeling Changed OurFreshman Physics Program?

• In regular Freshman Physics, breadth has been sacrificed for depth

• The teaching has become much more student centered and less teacher centered

• Students leave the course with better thinking skills, analysis skills, and ownership of the concepts they have studied in physics

• In Honors Freshman Physics, the depth of study has been significantly increased.

Why a Different Approachto Physics Instruction?

• Research shows that after conventional instruction, students cannot fully explain even the simplest of physics concepts.

• Worse yet, conscientious conventional instruction delivered by talented (and even award-winning teachers) does not remedy the situation significantly

What has NOT made a difference in student understanding?

• Lucid, enthusiastic explanations and examples

• Dramatic demonstrations• Intensive use of technology• Textbooks• Lots of problem solving and

worksheets

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 mathematical 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.

What is a Model?

• with explicit statements of the relationships between these representations

Symbolic Representations

PhysicalSystem

MentalModel

Verbal

Algebraic

Diagrammatic

Graphical

Multiple Representations

• with explicit statements describing relationships

How is it Different fromConventional Instruction?

constructivist vs transmissionist cooperative 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

How does Modeling change the responsibilities of the instructor?

• Designer of experimental environments

• Designer of problems and activities

• Critical listener to student presentations, focusing on what makes good arguments in science

• Must establish a trusting, open, “OK to make a mistake” classroom atmosphere

• Less visibility

The Modeling ProcessMaking Models

• 1) Construction– Identify system and relevant properties; represent

properties with appropriate variables; depict variables and their associations mathematically.

• 2) Analysis– Investigate structure or implications of model.

• 3) Validation (reality check!)– Compare model to real system it describes;

adequacy depends on fidelity to structure and behavior.

The Modeling ProcessUsing Models

• 4) Deployment (or application) Use of a given model to achieve some goal.

– Describe, explain, predict, control or even design new physical situation related to original.

– Infer conclusions from the outcomes of the model.– Extrapolate model for studying situations outside

original domain.– Examine and refine one’s own knowledge in terms

of the new modeling experience.

Modeling Cycle• Development begins with paradigm

experiment.– Experiment itself is not remarkable.

– Instructor sets the context.

– Instructor guides students to • identify system of interest and relevant variables.

• discuss essential elements of experimental design.

I - Model Development

• Post-lab analysis• whiteboard presentation of student findings

• multiple representations»verbal»diagrammatic»graphical»algebraic

• justification of conclusions

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 DeploymentObjectives:

• 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.

Adjustments to Curriculum:Freshman Physics

• Start with CASTLE electricity– Introduces modeling with minimal math– Last unit bridges to mathematical modeling

• Uniform Motion• Uniform Acceleration• Forces and Newton’s Laws• Electrostatics• Energy• Mechanical Waves

Adjustments to Curriculum:Honors Freshman Physics

• Uniform Motion• Uniform Acceleration• Newton’s Laws• Energy• Electrostatics• DC Circuits• Mechanical Waves

How are the Courses Different?

• Expected fluency with algebra• Amount of mathematical problem solving• Required “studentship” skills• Depth of coverage

Placement: Which Students in Which Course?

• Eighth Grade Teacher Recommendation

• Ninth Grade Math Placement

• Results of Science Reasoning Test

• Results of EXPLORE test

Placement Results

• Typically about 25% of the students end up in Honors Freshman Physics

• About 68% take Freshman Physics

• The remaining 7% take Algebra/Physics, and integrated math/science course.

Who Teaches the Course?

• Value good teacher of freshman over physics content specialist

• Chemistry and Biology specialists have taught the course

• Difficult to teach using Modeling Method without formal training

• Insist on Modeling Training as a condition of hiring

Does it Replace Physics in theJunior or Senior Year?

• No! This was not our goal.• Physics at the Freshman year is the

foundation of our Science curriculum• Physics in the Senior year is improved and

can now explore a broader range of topics.• Physics enrollment in the Senior year has

remained fairly steady, averaging about 20 to 25% of the student body

• All students get some physics!

Are Students Successful?

• Low failure rate• FCI scores for regular freshmen comparable to

those from traditional senior level physics courses.• FCI scores for Honors freshmen are significantly

above those from traditional senior level courses and even above those for most modeling courses.

• FCI scores for seniors entering do not diminish (and even increase) between grades 9 and 12

• FCI scores for seniors at completion are at the top• Students scoring above state average on MAP

Are Students Successful?

• Winners of Division 2 in Region 12 of Physics Bowl four times

• Top ten finish in TEAMS competition every year since 1993

• Six national championships in TEAMS competition• Twice finished first and second in nation in

TEAMS competition• First Place in Saint Louis University High School

Physics competition eight of last nine years• 85% “five” rate on A.P. Physics exam

Conclusions

• Freshman physics makes chemistry more meaningful/understandable

• Biology teachers are ecstatic about the changes they have been able to make in the curriculum

• 100% enrollment in Physics• Nearly 100% enrollment in four years of science

despite two-year state requirement for graduation• Students, Teachers, Parents, and School Board are

happy with the change.

Physics First at Clayton High School

Rex Rice

Clayton High School

1 Mark Twain Circle

Clayton, MO 63105

rex_rice@clayton.k12.mo.us