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 Ten
National Education Association
1892
Recommendations 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-Physics
Sequence at Turn of Century
Start with biology because:
1. Relied mostly on memorization
2. Required almost no mathematics
Reasons for Traditional
Biology-Chemistry-Physics
Sequence at Turn of Century
Follow with chemistry because:
1. Relied mostly on memorization and
detailed experimental procedures
2. Required only modest amounts of
mathematics
Reasons for Traditional
Biology-Chemistry-Physics
Sequence at Turn of Century
Make physics last because:
1. Required greater mathematical
fluency
2. Relied heavily on problem solving,
analysis, and critical thinking
Advantages of Teaching
Physics 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 Teaching
Physics 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 School
Clayton, Missouri
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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 PhysicsChemistry-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: ‘91/92
Text: Conceptual Physics-Hewitt
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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/’92
Based on “Quantitative Science”
• Geometric Optics
1.
2.
3.
4.
5.
Plane Mirrors
Pinholes
Curved Mirrors
Refraction
Lenses
Honors Freshman Physics: ‘91/92
Based on “Quantitative Science”
• Mechanics
1.
2.
3.
4.
Uniform Motion
Uniform Acceleration
Newton’s Laws
Work, Power, Energy
Honors Freshman Physics: ‘91/92
Based on “Quantitative Science”
• Electricity and Magnetism
1. Electrostatics
2. D.C. Circuits
3. Magnetism
Transition to
Physics-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 Our
Freshman 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 Approach
to 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?!
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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?
Symbolic Representations
Verbal
Physical
System
Algebraic
Mental
Model
Diagrammatic
Graphical
• with explicit statements of the relationships
between these representations
Multiple Representations
• with explicit statements describing
relationships
How is it Different from
Conventional Instruction?
constructivist
cooperative inquiry
student-centered
active engagement
student activity
student articulation
lab-based
vs
vs
vs
vs
vs
vs
vs
transmissionist
lecture/demonstration
teacher-centered
passive reception
teacher demonstration
teacher presentation
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 Process
Making 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 Process
Using 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
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whiteboard presentation of student findings
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multiple representations
»verbal
»diagrammatic
»graphical
»algebraic
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justification of conclusions
II - Model Deployment
• In deployment activities, students
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learn to apply model to variety of related situations.
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identify system composition
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accurately represent its structure
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articulate their understanding in oral presentations.
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are guided by instructor's questions:
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Why did you do that?
How do you know that?
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:
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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
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Uniform Motion
Uniform Acceleration
Forces and Newton’s Laws
Electrostatics
Energy
Mechanical Waves
Adjustments to Curriculum:
Honors Freshman Physics
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Uniform Motion
Uniform Acceleration
Newton’s Laws
Energy
Electrostatics
DC Circuits
Mechanical Waves
How are the Courses Different?
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Expected fluency with algebra
Amount of mathematical problem solving
Required “studentship” skills
Depth of coverage
Placement: Which Students in
Which Course?
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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 the
Junior 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