Title: Physics research: Interesting questions, Interesting Independent Lab projects
1Physics researchInteresting questions,
Interesting Independent Lab projects
- Daniel W. Koon
- Spring 2005
2Goals of this talk
- Describe some general subtopics of physics
- Solid State physics
- Optics
- Describe some interesting research questions,
including my own research - Suggest some Independent Lab project ideas
3Structure of this talk
- Solid state physics
- Research areas
- project ideas
- Optics
- Research areas
- project ideas
- Miscellaneous project ideas
4Solid state physics charge transport
- Charge transport
- the measurement of resistivity and Hall effect
- a cheap sub-atomic microscope
- A cheap sub-atomic microscope How so?
- Its cheap
- It explores how the molecules of the material
treat their electrons
5Resistivity, r
- Resistance, R measures how an object resists the
flow of current - Resistivity, r measures how a material resists
the flow of current - So, (SAT flashback)
- r R Density mass
- G(size,shape) R
6The Hall coefficient the other charge transport
quantity
- The Lorentz force
- Gives rise to a Hall voltage
- (The Hall effect is the bending of current due to
a magnetic field.)
7Punchline charge transport as a cheap subatomic
microscope
- Since
- we can deduce the microscopic quantities by
8Koons solid state interests
- I. The phenomenology of charge transport
measurement - Error analysis What do you measure when you
measure r, RH? - Is there a best sample shape?
9Error analysis How to do it
- Using computer to model current flow in the
specimen - To compare different geometries
- To test effects of thickness
- Using a discrete-resistor model in the laboratory
- To test linearity of the effect
10Koons solid state interests
- II. Applying charge transport measurement to
specific materials - Hydrogen absorption in rare-earth/Pd bilayers
- Challenges
- Rare earths corrode in O2.
- Pd overlayer stops corrosion, allows H2
absorption. - Pd is a much better conductor.
- So, how do you measure the properties of just the
RE?
11Interesting Solid State questions
- Is the effect of resistive inhomogeneities
linear? Is it additive (If I poke twice as big a
hole in a film does it produce twice the effect?) - Can we simultaneously measure the resistivity and
transmittance of a hydriding or corroding film? - How does the resistivity, Hall coefficient of a
material change as it freezes/thaws?
12Optics Biomaterials and more
- Photonic Polar bears?
- Solar efficient butterflies?
- Ulexite (TV rock)
- Scarlet macaws
13- The hairs of the polar bear are transparent light
pipes that direct ultraviolet light to its skin
-- which is guess what color? Black! So whats
white and black and warm all over? A polar bear
under the arctic sun. - Paul G. Hewitt, Conceptual Physics, 6th Edition,
1989, p. 501
14- Aristotle maintained that women have fewer
teeth than men although he was twice married, it
never occurred to him to verify this statement by
examining his wives mouths. - Bertrand Russell
15Optical attenuation spectrumpolar bear hair
16FOUL(UP)A Fiber-Optic Ursine Link (Universal
Prototype)for telecommunicationsD. W. Koon and
C. L. Jahncke, Physics Dept., St. Lawrence
University
- ABSTRACT We have constructed what we believe
is the first prototype of a fiber-optic link to
use the hair of an Arctic mammal. The potential
advantages of ursine fiber technology over
conventional technology are discussed. - http// it.stlawu.edu/physics/clj/foulup.html
17Interesting Optics questions
- Polar bear hairs as optical fibers?
- Reid Hutchins 98
- Morpho butterflies Does iridescence serve as a
solar panel or a sunblock? - Andy Crawford 99
- Ulexite (TV rock) Is there cross talk in the
fiber optic bundles? - Jay OBrien 98
- The scarlet macaw Thin-film iridescence, or
diffraction grating, or what?
18Miscellaneous interesting questions