What is Physics? (ppt 3225 kb)

advertisement
What is Physics?
Derek Raine (and many others)
LeA
Project
www.ou.ac.uk/picetl
www.le.ac.uk/i-science
www.le.ac.uk/leap
www.integratedsciences.org
Here’s one definition…
Standard model Lagrangian:
 

[ L~  iD L  eR   iD eR
(e, , )


 me (eL eR  eR eL )]  12   h  h  m 2 h 2  14 Z  Z   14  0 ( g1  g 2 ) Z  Z 
2
 14 A A





2
2

 12 ( DW )*  ( D W )* D W   D W    12 g 2 0 W W  

1
4
h2 
1
2


h0 g 2 W W    12 ( g1  g 2 ) Z  Z 
2
2
2
2

2
2


m 2h3 m 2 h 4 g 2







W W  W W W  W   W  W 
2
4
20 80

ig 2
A sin  w  Z  cos w  W W   W W 
2
2


 g 2 cos 2  w Z  Z W W   Z  Z  W W  


ig 2
cos  w
2

Z W






 Z W

D W


 

 D W    Z W  Z W

( D W

and the rest…
 *
)  ( D W   )*


 u
flavours

~  i    i(2e / 3) A u L  u R   i   i(2e / 3) A u R

L




 d L ~  i    i(e / 3) A u L  u R   i   i(e / 3) A u R
  [md (d L d L  d R d R )  mu (u L u R  u R u L )]








e
e

 Z  (1  (4 / 3) sin 2  w )  u R  u R 
 Z  (4 / 3) sin 2  w
  [u L   u R 
 sin( 2 w ) 
 sin( 2 w ) 




e
e

 Z  (1  (2 / 3) sin 2  w )  d R   d R 
 Z  (2 / 3) sin 2  w ]
 d L ~  d L 
 sin( 2 w ) 
 sin( 2 w ) 
Vud
e


 

(u L , cL , t L ) Vcu
2 sin  w
V
 td

8
1
4
 G G a 
a 1
a
Vus Vub  ~  d L 
 ~   
Vcs Vcb   sL W  h.c.
Vts Vtb  ~  bL 
[q i  (   igG )q
f
f
 mf q f q f ]
flavours
+ gravity
Here’s another definition:
the science of matter and energy and their
interactions
wordnet.princeton.edu/perl/webwn
And from good old Wikipedia
Physics (or "Physica", or "Physicae Auscultationes" meaning
"lessons") is a key text in the philosophy of Aristotle
Physics (from the Greek, φυσικός (phusikos), "natural", and
φύσις (phusis), "nature") is the science of Nature in the
broadest sense. en.wikipedia.org/wiki/Physics
Physics is an instrumental band from San Diego, California,
USA that has featured a rotating cast of musicians, but is
currently composed of Jeff Coad and Will Goff on synths, Rob
Crow, Jason Soares, and John Goff on guitars, and Cameron
Jones on drums.
en.wikipedia.org/wiki/Physics_(band)
Why do we need to ask the question?
The European Union (EU) has set a
goal of becoming "the most
competitive and dynamic knowledgebased economy in the world by
2010."
Growth of university science education
National Science Board. 2004. Science and Engineering Indicators 2004. Two
volumes. Arlington, VA: National Science Foundation (volume 1, NSB 04-1;
volume 2, NSB 04-1A).
Growth in higher education in the UK
participation rate in HE in the UK
percentage
participation
40
3233
30
20
10
0
1850
6
1
1900
1950
year
2000
2050
The retreat from science
Attitudes to physics and chemistry
•
After instruction, students, on average, are found to be less expert-like in their
thinking than before. They see physics as less connected to the real world, less
interesting, and more as something to be memorized without understanding.
This is true in almost all courses, including those with teaching practices that
have substantially improved conceptual mastery.
•
CLASS Categories
•
•
•
•
•
•
•
Reality Personal View Physics is part of the student’s life – student cares about physics.
Reality World View Physics describes phenomena in the World around us.
Math Mathematical formulae describe physical phenomena.
Sense Making It is important to me to make sense out of things when learning physics.
Metacognition Awareness of what is necessary to learn and understand physics – self reflection.
How to Learn Best learned by memorization of facts and methods without understanding.
Coherence Physics consists of connected ideas.
•
•
Calc-I LSRU/Fa03 engineers
63% 65%
Calc-I MMSU/Fa03 physics maj 64% 54%
The Design and Validation of the Colorado Learning Attitudes about Science Survey
W. K. Adams, K. K. Perkins, M. Dubson, N. D. Finkelstein and C. E. Wieman
CLASS (Colorado Learning Attitudes about Science Survey).htm
The UK External Environment
University entrants 1985-1999 (scaled to total)
fraction of entrants per subject
0.04
0.035
0.03
Physics
0.025
Maths
0.02
Chemistry
Biology
0.015
0.01
0.005
0
1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000
year
since 1994, the number of UK universities offering
degrees in physics has declined from 79 to 51
Physics BSc graduates working in the UK
Physics related employment
Information Technology
What is Physics – View from the IOP
Mechanics and Relativity
17th Century
Classical mechanics: Newton’s laws, conservation laws, rotation, Newtonian gravitation, Kepler’s laws,
Special relativity to the level of: Lorentz transformations and energy momentum relationship
Quantum Physics
Background to QM to include:
early 20th Century
Black body radiation, Photoelectric effect, Wave-particle duality, Heisenberg’s Uncertainty Principle
Schrödinger wave equation to include:
Wave function and its interpretation, Standard solutions and quantum numbers, to the level of the hydrogen atom,
Tunnelling, First order time independent perturbation theory
Atomic, nuclear and particle physics to include:
Quantum structure and spectra of simple atoms, Nuclear masses and binding energies, Radioactive decay, fission and
fusion, Pauli exclusion principle, fermions and bosons and elementary particles, Fundamental forces and the Standard
Model
Condensed Matter Physics
early 20th Century
Mechanical properties of matter to include elasticity and thermal expansion, Inter-atomic forces and bonding, Phonons
and heat capacity, Crystal structure and Bragg scattering, Electron theory of solids to the level of simple band
structure, Semiconductors and doping, Magnetic properties of matter
Oscillations and Waves
19th Century
Free, damped, forced and coupled oscillations to include resonance and normal modes, Waves in linear media to the
level of group velocity, Waves on strings, sound waves and EM waves, Doppler effect
Electromagnetism
19th Century
Electrostatics and magnetostatics, DC and AC circuit analysis to complex impedance, transients and resonance,
Gauss, Faraday, Ampère, Lenz and Lorentz laws to the level of their vector expression, Maxwell’s equations and plane
EM wave solution; Poynting vector, EM spectrum
Polarisation of waves and behaviour at plane interfaces
Optics
mainly 19th Century
Geometrical optics to the level of simple optical systems, Interference and diffraction at single and multiple
apertures, Dispersion by prisms and diffraction gratings, Optical Cavities and laser action
Thermodynamics and Statistical Physics
Zeroth, first and second laws of thermodynamics: 18th – 19th Century
Temperature scales, work, internal energy and heat capacity, Entropy, free energies and the Carnot Cycle, Changes
of state
Statistical mechanics:
early 20th Century
Kinetic theory of gases and the gas laws to Van der Waals equation, Statistical basis of entropy
Maxwell-Boltzmann distribution, Bose-Einstein and Fermi-Dirac distributions, Density of states and partition function
OK – so I’m cheating a bit
– the standard model is 1970s !
A. PHYSICS SKILLS
Students should learn:
1 How to tackle problems in physics and formulate an appropriate
solution.
For example, they should learn how to identify the appropriate physical principles; how to use special and limiting cases,
dimensional analysis and
order-of-magnitude estimates to guide their thinking about a problem; and how to present the solution making their
assumptions explicit.
2 How to use mathematics to describe the physical world.
They should know how to turn a physics problem into a mathematical form and have an understanding of mathematical
modelling and of the role of approximation.
3 How to plan, execute and report the results of an experiment or
investigation.
All graduates of an accredited degree programme should have some appreciation of physics as an experimental science.
They should have an understanding of the elements of experiment and observation and should therefore be able to
• plan an experimental investigation; • use apparatus to acquire experimental data; • analyse data using appropriate
techniques; • determine and interpret the measurement uncertainties (both systematic and random) in a measurement or
observation; • report the results of an investigation; • understand how regulatory issues such as health and safety influence
scientific experimentation and observation. For many degree programmes, experimental work in a conventional laboratory
course will be a vital and challenging part and will provide students with the skills necessary to plan an investigation and
collect and analyse data. However, these required skills may also be acquired through computer simulation, paper exercises
with appropriate data, or case studies using real experimental data from a published source. Other methods may be used
provided they meet the above objectives.
4 How to compare results critically with predictions from theory.
Students should understand the concept of using data to test a hypothesis and be able to assess the reliability of data, to
understand the significance of results, and to relate results from numerical modelling or experiment to the relevant theory .
B. TRANSFERABLE SKILLS
A Physics degree should enhance
Problem-solving skills
Physics degree programmes involve students in solving physics problems with well-defined solutions. They should also
gain experience in tackling open-ended problems. Students should develop their ability to formulate problems in precise
terms and to identify key issues. They should develop the confidence to try different approaches in order to make progress
on challenging problems.
Investigative Skills
Students should have opportunities to develop their skills of independent investigation. They should develop the ability to
find information by using textbooks and other available literature, by searching databases and the Internet, and through
discussions with colleagues.
Communications skills
A physics degree should develop students’ ability to communicate complex information effectively and concisely by means
of written documents, presentations or discussion. Students should be able to use technical language appropriately.
Analytical skills
Students should develop their ability to grasp complex concepts, to understand and interpret data precisely and to
construct logical arguments. They should be able to distil a problem to its basic elements.
IT skills
Students should become familiar with appropriate software such as programming languages and packages. They should
develop their computing and IT skills in a variety of areas including the preparation of documents, information searches,
numerical calculations, and the manipulation and presentation of data.
Personal skills
Students should develop their ability to work independently, to use their initiative and to organise themselves to meet
deadlines. They should gain experience of group work and be able to interact constructively with other people.
Units
Averages
Rates of change
Orders of magnitude
Estimates
Proportionality
Intensive and extensive
variables
Graphical analysis
Derivation of hypothesis from
experiment
Discrediting of a hypothesis
by experiment
Classic experiments
overturning prior beliefs
Use of a physical law for
prediction
Phenomenological laws
Physical Reductionism
Use of Analogies
Mathematical models
Change of frames of reference
Symmetry
Conservation laws, (energy,
momentum)
Open and closed systems
Equilibrium, dynamic equilibrium
Irreversibility
Description of bulk properties in terms
of constituents
Fluctuations
Transport
Wave concepts
Resonance
Frequency space
Phase space
Concept of a field
Quantum properties
Science education and economic
development
The Relevance of Science Education
study, which looked at 15-year-olds in 40
countries, found a 0.92 negative
correlation between attitudes to school
science and the UN index of human
development.
Problem-based learning
Motion in 1D
Dimensional analysis
Kinematics
Dynamics
Conservation laws
Motion in the plane
Problem: The lead shot used in shotgun
cartridges consists of small spherical pellets 23mm in diameter made by pouring molten lead
through a frame suspended in a high tower, a
method used since its invention by William
Watts in 1782. In order to produce spherical shot
the lead must solidify before the pellet has
reached terminal velocity. How high should the
tower be?
Problem A design for a spaceship that would
also function as an orbital space station might
look like the dumbell form of Spaceship USS
Discovery 1 from the film 2001: A Space
Odyssey. The picture shows an artist’s
impression with the spaceship moving round the
Circular Orbits
Earth oriented like a plane flying through the air.
Equilibrium and Stability
Dynamics of rotational motion Is there anything wrong with this?
Simple Harmonic Motion
Oscillations
Problem: The Tour Sans Fins ("Tower Without
Ends") was a tower planned in La Defénse that has
since been cancelled. The spelling Tour Sans Fins
(rather than the apparently correct French fin) comes
from the idea that this tower had no ends, even if one
looked up or down at it, hence "ends" and not "end".
The Tour Sans Fins was meant to be 400m tall and
would have been the tallest skyscraper in Europe.
and Waves
Oscillators
Projectiles
Properties of waves
Water waves
Current electricity
Resistance
Capacitors
AC circuits
Oil level in capacitor
Resistor
AC source
speaker
Problem: An ocean-based tsunami detection buoy has
been successfully deployed 1200km southeast of
Tasmania. How much warning will this give?
Problem: Heart defibrillators, which are used to
restore a regular heart beat, stimulate the heart to
contract by delivering a short current pulse of duration
20 ms. In one type of defibrillator a capacitor is
charged to a suitable voltage and then discharged
through the patient's chest with the aid of two large
electrodes. The defibrillator needs to be able to deliver
pulses of up to 360 J to patients with transchest
resistances ranging up to 150 ohms. Estimate values
for capacitance and voltage needed to cope with these
requirements.
Problem: The figure shows a proposed device for
measuring oil level. As the oil level changes so does
the capacitance. At a certain level the speaker sounds
as a warning. What values of the circuit elements could
be used?
Motion in 1D
Problem: Making lead shot
Dimensional analysis, Kinematics
Dynamics, Conservation laws
Motion in the plane
Problem: What’s wrong with the artists impression?
Circular Orbits
Equilibrium and Stability
Dynamics of rotational motion
Simple Harmonic Motion
Oscillations and Waves Oscillators, Projectiles,
Properties of waves, Water waves
Problem: The Tour Sans Fins ("Tower Without Ends")
Problem: Warning from an ocean-based tsunami detection buoy?
Resistance, Capacitors, AC circuits
Problem: Heart defibrillators
Problem: Oil level warning
Electric & Magnetic Fields Electric fields, Fields
Problem: How can linesmen work safely on live wires?
Current electricity
and potentials, Capacitance, Currents and magnetic
fields
Magnetic Fields
Problem: What is happening in the pictures?
Dipole fields
Magnetic Induction
Magnetic forces
Magnetic materials Magnetic forces in Equilibrium
Problem: Can a frog levitiate?
Paramagnetism, Ferromagnetism,
Electromagnets, Diamagnetism
Electromagnetic waves
Problem: Detecting leaking water pipes in the desert.
Electromagnetic waves, Fields at Boundaries,
Reflection and refraction, Water pipes in the desert
Geometrical optics
Reflection, Refraction , Lenses
Problem:
How do glasses work?
Problem: Explain a diffraction pattern
Physical Optics
Wave properties and superposition,
Interference, Diffraction
Atomic structure
Problem: Detecting Atmospheric contaminants
Nuclei and radioactivity
Problem: Oklo mine natural reactor.
Quantum phenomena
Problem: Teleportation
Heat
Problem: Towing icebergs
Thermodynamics
Problem: The gas pressure driven car
Solids and fluids
Problem: Biophysics of Giraffes, Sharks, Fleas, Antelopes, Flies and Trees
Condensed matter
Problem: Nanobiomarkers
Transport properties
Problem: UltraKleene
Relativity
Problem: GPS
Astrophysics
Problem: How did the Universe grow?
Another curriculum!!
PBL Problem
Physics Topics
The White Knuckle Toy
Newtonian dynamics, oscillations, damping
Crosswind Warning
Electrostatics, induction, steady currents,
fluids
The Art of Glass
Geometric and wave optics
UltraKleene
Kinetic theory, Diffusion
Chocolate Factory Alarm Circuits, AC theory
Space Tether
Newtonian gravity, elasticity
Solid State Traffic Lights
Semi-conductors, LEDs
Desert Pipeline Leak
Electromagnetic theory
Transporter
Quantum theory
Air Quality
Spectroscopy
Interdisciplinary Challenges
• Global warming
Interdisciplinary Challenges
• Biodiversity
Interdisciplinary Challenges
Sustainability
Interdisciplinarity
Interdisciplinarity
Interdisciplinarity
Random Walk
(Brownian Motion)
Interdisciplinarity
Download