 Diffraction rings in a misted mirror. |
 Enlargements. |
Selecting a Topic
"A rose by any other name ... " SUBJECT SPECIFIC ASSESSMENT CRITERIA:
A Good PHYSICS extended essay will:
Select a topic that interests you and seems practical. Consider carefully the time and resources available. Develop a question. Keep these points in mind:
1 An essay explores a single topic in depth that involves a topic in Physics within the range of general scientific standards. If you touch on several topics under a global heading you will get a C. The original essay, Mirages and the green flash was too ambitious and consequently did not earn an A. The original essay has been split into two separate topics in the essays index. A much shorter piece about the generation of one particular illustration, Reisland's Model, did earn an A.
2 A good essay in Physics will normally contain a review of published material in an introduction, but there must be a section of the student's own work. Select a topic for which you can make some personal contribution. You may address a sports topic: if it is treated from the viewpoint of Physics.3 A question is required. A good question for an essay, is not the same thing as a good research question for a lab. An essay does not begin with a specific hypothesis and explanation. A lab answers a specific question, an essay discusses a question. There is a difference. An essay question is of more general interest, and is discussed in the light of either quantitative or qualitative data.
4 An essay registered in Physics will be judged as such. For instance, an essay dealing with the perception of three dimensional illusions, which borders on Psychology, will, if registered as a physics essay be judged on the physical content. If the data and analysis are related to relative motion and the intensity of illumination (Pulfrich's illusion) the essay is appropriately categorized as Physics. If the focus of the essay is perception itself, then it would be better to register it as an essay in Experimental Psychology.
5 An essay will normally include measurements made by the student, but it could be based on the reinterpretation of already-published data, it could be theoretical, or it could involve a validity-critique of the literature of a topic.
Topics for which students from ISB were awarded A grades. Edited versions of most of these essays are in the Essays file.
A new model of the two source interference pattern
Sam Reisland, 1998
The 22° ice crystal halo
Surat Techipibal, 2000
The oscillations of vibrating bars
Marissa Hemingkorn, 2000
Visual processing delay - A quantitative investigation using Pulfrich's illusion
Bradley Skaggs, 2000
The topography of the dominant mode of vibration in an inflated ball
Tomonari Miyashita, 2001
The energy of a standing wave on a weighted bungee
Thomas Atwood, 2004
Corking: aspects of skydiving modeled in water
Daniel Chang 2006
A selection of successful essays from ISB students that returned a B grade when judged against the stated criteria for technical reasons; or possibly because the essays were assisted, or they contained too little physics. In some cases the topics did not match the criteria [to broad a topic or a mixture of topics etc]. In some cases the essay itself contained inconsistencies, bad grammar and obscure passages. Edited versions of most of these essays are in the Essays file.
Camera lenses: construction and analysis
Akanksha Mehta, 1998
Singing Bowls
Alex Hayden - Gilbert, 1998
Pile driving
Tal Brown, 1998
Stereopsis - The Binocular Perception of Depth
Kuk-Hyoe Koo, 2000
Astigmatic water lenses
Terje Halls, 2001
Resonance in Cups
Xin-Yi Yeap, 2002
ROYGBIV: the colors of the rainbow?
Amy Smith, 2004
The properties of a rattleback
Afzal Hasan, 2004
The dispersion of ripples on water and alcohol
Porsche Horesaengchai: 2006
Possible experimental topics.
.
- Irregular bowls and bells
We have a reprint of a book by Helmholtz (1877) and sound analysis software. Explore the graphs that Helmholtz never saw. The FFT and the oscilloscope trace for a malformed bell. Question: is an addition equivalent to a deficit (made by drilling near the rim)?
- An analysis of the rotating nodes and the two beating frequencies of a stroked, weighted, wine glass
It is possible to observe, and to film, the rotating nodes directly with water (or coffee) in a suitable wine glass, and to obtain FFT spectra at the same time. The effects of water inside and outside a wine glass on the frequencies when stroked or tapped is also an interesting topic.
- *Reflection from open and closed boundaries
What are the exact details of reflection of water waves from closed and open boundaries and what apparatus could be constructed to film the events?
- The dynamics of winged seeds
There are several local types. Many things could be done.
- Amplitude measurements in a ripple tank
The intensity of any wave is proportional to amplitude squared - the amplitude-distance relationship for radiation from a point source in a ripple tank is therefore inverse square root. Is it?
- * The thin lens formula applied to ripples
The lens-mirror formula applies in a tank. I have never seen illustrations in a text showing this ... well worth a try. (See Concave mirrors.)
- Interference and diffraction effects associated with a misted or dusty mirror
Consult an excellent article by N J Bridge, (available elsewhere in .pdf format), or contact james@xmas.demon.co.uk. Obtain your own photographs under varied conditions and write an essay about a selected aspect.
Sample photographs from Bridge's paper.
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Diffraction rings in a misted mirror. |
Enlargements. |
- Wakes and boat speed
A wake is a shock wave. Measure boat speed from photographs taken of the river from upper hotel windows. What else could be done?
- *Seiche waves
What could be done with a fish tank?
- The monocular perception of depth
3D images can be constructed when only one eye is used. Relative size and intensity are weak clues, except in special circumstances.
Relative motion is much stronger.
Extend the inverted cube illusion. [Probably a better topic for an experimental psychology essay.]
- * The effect of ambient light intensity on visual acuity
- * The effect of the color of print on visual acuity
- The Pulfrich effect
One essay has been done. There is scope for another.
- The Leidenfrost effect
Measurements could prove to be interesting.
- The dynamics of a winged seed
Measurements could prove to be interesting.
- Wall effects
A study of wall effects in either a Stokes' law or turbulent flow regime, in either a Newtonian or a non Newtonian fluid.
- * Steffan's law
Surface temperature can be measured with a remote sensing IR thermometer. What could be done with this facility
- Collision duration
Time on the floor for a bouncing ball can now be measured accurately in some situations with an accelerometer or the 100 f/s camera. A study in various situations would be productive.
- Cone angle
The cone angle of a volcano depends on the type of material ejected. Make a collection of images of Basaltic and Andesitic volcanoes. It would be interesting to investigate the cone angle for different types of rice, and to relate that to the coefficient of static friction between the grains. Try unhusked rice, brown rice, white rice, japanese rice, wild rice, basmati rice etc..
- Stress dip
Set up a line of force probes (with blocks mounted on the hooks) to measure the pressure as a function of the distance from the center of of piles of different grains. Pour the grains onto a plastic or soft thin rubber sheet sheet to make tidying up easier and to prevent grains from sticking in cracks around the force probe blocks. There may be differences in the pressure patterns for different grains in piles made in different ways.
- Projectile motion
A study of projectile motion with air resistance is now possible with a radar gun and film analysis software. Does the 45° maximum range for a given launch energy still hold?
- The sling-shot effect (simulations)
Newton's Aquarium could be used to clear up misconceptions about the sling-shot effect [using gravity to accelerate a solar system probe to outer planets without the need for fuel]. In two body interactions the probe velocity is not increased - it merely changes its direction of travel. In three body situations many things are possible.
- Moon capture
Newton's Aquarium can be used to demonstrate moon-capture which is a three body problem. There are many binary stars. There are very few double asteroids - why? This essay will answer that question.
Historical topics?
- An essay on some aspect of the history of Physics requires some content generated by the student. Thomas Young is remembered, among other things, for his demonstrations of the wave properties of light, to the consternation and eventual embarrassment of the English academic establishment, who had adopted Newton's flawed optics. Repeat Young's observations with sunlight and a sliver of card. Few in the modern world have seen what he saw. Bring his observations into the modern world with lasers etc. A high-end digital camera may be required to obtain good images. [Suggested topic: Tue Sowerprux.]
- What about early telescopes and microscopes, Joule's water paddles, Toricelli's barometer, Kelvin's water drop generator, or Galileo's thermometer. Not interesting or productive enough as topics in themselves, but any one of them could be used in an introduction to an essay. For instance, Galileo's thermometer could be used as the introduction to an essay on the construction of hydrometers, sensitive enough to measure water temperature, or parts per million of salt in water.
- Explore some aspect of the development of camera lenses with a digital SLR camera. Uncut meniscus spectacle lenses make interesting compound camera lenses.
The names in the history of physics were real - we can read what they wrote.
Other options?
There are websites where bad physics, and specifically, mistakes in books are discussed. Here is a list of just a few that occur very often ...
- Nuclear decay is not affected by temperature or chemical composition.
- A wave reflects from a closed boundary with a phase change, setting up a standing wave.
- Tension is a vector.
- V = +IR
- Electricity is a synonym for current and/or power.
- The spectrum has seven colors (ROYGBIV).
- Cosmic rays come from the Sun.
An introduction quoting web sites and/or the late Richard Feynman on errors in texts, and then a book search to find examples could work if done well. It would be difficult to take one book (or a set of IB papers) and find all the errors. It might be better to select one error, and to look for that in many books, papers, and/or websites.
You could try ...
Electricity is a subject!
The word electricity is very often confused with electric current and with power. Once you understand the distinction, the misuse of the term in texts and the public press becomes obvious.
- Physics in the environment
We live in Bangkok. Clouds display many physical characteristics that are seldom seen elsewhere.
- Select one type of cloud that illustrates an aspect of the properties of a non-uniform atmosphere. Make a collection of photographs and write an essay around them.
- Make a model of a k-h instability and illustrate the phenomenon in the atmosphere with your own photographs.
- Select one type of mirage and simulate it in a tank.
- Model and discuss the properties of a tropical lake - making measurements in the Nichida lake (good luck).
- The use of animations and simulations in the communication of physical ideas
You could do a search for old illustrations and modern style illustrations and compare them. You could discuss the difference between animation and simulation and discuss the advantages of the simultaneous presentation of a graph and an animation at the same time.
*You could construct your own illustrations using Flash or an Applet Builder.
- * The Whole Vector Method".
Avoid wind-tunnels unless you have a very specific idea. The topic involves too much time building, and not enough simple physics. Avoid X-rays, home-made guns, and solid fuel rockets; for obvious reasons. The boy who wanted to launch rockets with trailing copper wire into thunderstorms was discouraged. Avoid the magnus effect - it is very difficult to get good data.
Read the Papers section of this CD, both papers and notes, for ideas. To cast a larger net for ideas, try the archive of How Things Work If this archive is not on the web, we have a June 4 2004 edited version on this CD. It's big.
Even better is this offering from ...
http://www.flyingcircusofphysics.html
If this is not on the web, there is a 2007 archive here.
