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•Physics is a fundamental science which explains natural phenomena and those produced in laboratories.

A modern interpretation of physics requires:

• Sophisticated mathematical models (calculus-

based, group theories, Fourier analysis, etc.).

• Counter-intuitive representations.

• Probabilistic rather than deterministic interpretation.

• The duality of the light, atoms, and electrons as

waves and particles.

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Methods of teaching physics

• Conventional teaching: Classical lecture

followed by laboratory activities on selected topics.

• Problem-based learning (PBL).

• Peer-instruction (PI) under instructors’supervision.

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Conventional teaching• Conventional teaching lies in the presentation of the

material, which frequently comes straight out of

textbooks and/or lecture notes. A traditional lecture is

nearly always delivered as a monologue in front of a

passive audience. Only exceptional lecturers are

capable of holding students' attention for an entire

lecture period. It is even more difficult to provide

adequate opportunity for students to critically think

through the arguments being developed.

Most (83%) instructional faculty use lecture/discussion as the primary

instructional method for undergraduate classes.

( NSF - S&E Indicators 2008. Chapter 2. Higher Education in Science and Engineering )

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Problem-based learning (PBL)

• PBL is a student-centered instructional strategy in

which students collaboratively solve problems and

reflect on their experiences.

• It was pioneered by Barrows and Tamblyn in 1980, and

used extensively at McMaster University, Hamilton, Ontario,

Canada.

• The characteristics of PBL are:

* Learning is driven by challenging, open-ended problems.

* Students work in small collaborative groups.

* Teachers take on the role as "facilitators" of learning.6

Historical roots of PBL

Initially, PBL questioned how well traditional preclinical science

courses trained physicians to be problem-solvers and life-long

learners. Information-dense lectures presented by a series of

content experts to large student audiences seemed disconnected

from the practice of medicine that required integration of

knowledge, decision making, working with others, and

communicating with patients. The curricula of several medical

schools now include problem-based, preclinical science courses.

Students are encouraged to take responsibility for their group and

organize and direct the learning process with support from a tutor

or instructor.

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• Merrill (2007) (A Task-Centered Instructional Strategy.

"Journal of Research on Technology in Education”, 40

(1), 33-50) suggests beginning with worked examples

and then later, introduce students to smaller less

complex problems. But as the process progresses,

Merrill suggests changing problems by adding

components to make them more realistic. Thus it is

important to begin with simplified versions of real world

problems to progressively add components. This

progression and fading motivates learners as they

slowly gain expertise and take ownership.

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Peer-instruction (1997)

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Peer-instruction model

• Peer Instruction involves students in their own learning

during lecture and focuses their attention on underlying

concepts. Lectures are interspersed with conceptual

questions, called ConcepTests, designed to expose

common difficulties in understanding the material.

Professor Eric Mazur Peer-instruction10

• The students are given one to two minutes to think

about the question and formulate their own answers;

they then spend two to three minutes discussing their

answers in groups of three to four, attempting to

reach consensus on the correct answer.

• This process forces the students to think through the

arguments being developed, and enables them (as

well as the instructor) to assess their understanding

of the concepts even before they leave the classroom.

Strategy of PI

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AIP - Statistics

Following a long-period of small growth, enrollment in S&E declined in

latter half of the 1990’s and then increased steadily since 1999.

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According to an NSF statistics (S&E Indicators

2008), in 2005, men earned the majority of BS

Degrees awarded in engineering (80%), and physics (79%).

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Employers in Texas that Recently HiredNew Physics Bachelor Recipients

_______________________________________________________________

• Bell Helicopter Textron

• Boeing

• Dell Computers• DuPont

• Electronic Data Systems• HIH Lab

• IBM

• M.D. Anderson Cancer Center• Princeton Review

• Samsung Austin Semiconductor

• Texas Instruments• United Space Alliance

• Universital Ensco, Inc.

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BS degrees awarded by field

• NSF – Statistics (1995 - 2005)

Year →→→→ 1995 2000 2005

All STEM fields 1,174,436 1,253,121 1,407,009

Science and Engineering (32%) 378,148 398,622 454,978

Biological Sciences (16%) 56,890 64,904 63,892

Engineering (16%) 63,371 59,536 64,675Computer Sci. (6.5% - 12.6%) 24,769 37,388 57,405

Mathematical sciences (3.5%) 13,851 11,735 13,755 Chemistry (2.6%) 10,016 10,390 9,305

Earth sciences (1.0%) 4,478 4,047 3,903Physics (0.9%) 3,836 3,362 4,156

Source http://www.nsf.gov/statistics/nsf07308/pdf/nsf07308.pdf.

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AIP - Statistics

• Teachers with academic background:

Holding any physics degree: 47%

♦ Physics major 22% and minor 10%.

♦ Physics education major 11% and minor 4%.

United States has the highest % of population ages 25-64 with a bachelor’s degree or higher. However, among the population 25-34, the United States (30%) lags behind Norway, Israel, the Netherlands and South Korea, and it ranks 10th (behind Russia, Canada, Japan, Israel, South Korea, Sweden, Belgium, Ireland, Norway) in the population ages 25-34 with any secondary degree.

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American Competitiveness Initiative (ACI)

• The American Competitiveness Initiative (ACI) is a federal assistance program intended to help America maintain its competitiveness through investment in research and education. ACI was supposed to focus is on programs that are likely to strengthen U.S. competitiveness by targeting funding to agencies that support research in the physical sciences.

• The ACI was a part of President George W. Bush’s State of the Union Address given on January 31, 2006.

• Unfortunately, the ACI was never funded.

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Methods of teaching physics

• Conventional teaching: Classical lecture

followed by laboratory activities on selected topics.

• Problem-based learning (PBL).

• Peer-instruction (PI) under instructors’supervision.

• Experimental-based learning (EBL).

Definition: Physics is a fundamental science which explains natural phenomena

and those produced in laboratories. 22

Experimental-based learning (EBL)

• EBL uses the laboratory as the central environment for understanding physical phenomena.

• EBL combines lab activities with lectures in a studio format, and alternates the theory, with solving-problem, and with hands-on experience.

• Learning through experimentation allows a better appreciation of the importance of physics and of the validity of theoretical models.

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Assessment of EBL

• The efficiency of the EBL technique was assessed in our Optics-related courses by

using three groups of students:

> Group A had a qualitative understanding of Optics (taught using the PI method);

> Group B acquired a quantitative knowledge (using the PBL method);

> Group C had a rich hands-on experience after taking an Optics lab.

“Experimental-based learning in optics as a way to reach academic performances”

National Forum of Educational Administration and Supervision Journal vol. 23,

No. 3, 2006-2007, pages 100-121. 24

Questionnaire

“Identify the links between the characteristics of light (wave and particle) and experiments of

• diffraction on a single slit (DSS), diffraction gratings (DG), Young double-slit interference

(YDS),

• photoelectric effect (PE), glowing objects (GO),

and Compton scattering (CS).”

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After taking a modern Optics laboratory course 90% of the students identify correctly the photoelectric effect (PE) and the radiation

emitted by a glowing object (GO) as being phenomena related to the photon theory of light, while 100% of the students identify the

experiments of diffraction and interference as the result of thepropagation of light as a wave.

Before taken an Optics laboratory course.

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American Journal of Physics, Bahrim and Hsu (April 2009)

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Stairstep NSF program

• Student Advancing through Involvement in Research Student Talent Expansion Program (STAIRSTEP)

– started in Jan. 1, 2009

• Its mission is to increase the number of STEM students in Computer Science, Mathematics, Chemistry, Geology and Physics.

• The goals are:

(1) retain talented at risk students;

(2) help transition them into advanced study or careers in science;

(3) attract more students to the field.

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Light is a waveExperimental proof: Diffraction and interference of light

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Diffraction and interference of light

• Diffraction is spreading out the light when it passes through small openings.

• A diffraction pattern has alternating bands of maxima and minima of intensity.

• When the light passes through multiple openings an interference pattern with many maxima and minima is formed, which is enveloped by the diffraction maxima.

scre

en

light

y

D

d

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Setup for interference and diffraction

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Diffraction of light on crystals

• Light patterns – allows to see the array of atoms in the crystal.

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Electron Diffraction

• When electrons are fired toward a crystal, the electrons are reflected in a way that resembles the diffraction-interference of light (the light patterns are formed).

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Wave packet for electrons

• Any particle in motion is characterized by a wave packet which represents the Fourier transform of a sinusoidal wave.

Light wave representation

Wave-packet

( ) ( )txkAtrii

i

iω−=Ψ ∑ sin,

r

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Duality wave - particle

• A basic characteristic of nature explained by physics using a complex mathematics (called wave packet) which is difficult to imagine.

• Could we fabric a wave packet?• Hypothesis: The interference phenomenon is

the superposition of sinusoidal waves, with many maxima and minima, and the diffraction is the envelope or the wave packet of these many maxima and minima.

• Analogy – broadcasting signals: carrier wave and information.

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Experimental results

2 slits 3 slits

4 slits 5 slits

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Acknowledgement

“Partial support for this work was provided by the National Science Foundation's Science, Technology, Engineering, and Mathematics Talent Expansion Program (STEP) under Award No. DUE 0757057. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation.”