10.9 Summary
- The novelty requirement can be fulfilled by showing originality with respect to: data; methods and techniques; research questions; research areas; or analysis and synthesis.
- Why-analysis can be used to explore the boundaries of knowledge and identify promising research problems. It helps us to penetrate layers of descriptive knowledge to a level where our understanding of a problem is finally challenged.
- Since research problems often are complex it is important to break them down into subproblems that can be handled, as well as setting a realistic scope for the research.
- Ishikawa diagrams allow us to summarize important relationships between an effect and its potential causes in a process or phenomenon.
- Cause-and-effect tables can be used to explore how we expect a potential cause to be coupled to its effect. They are thereby useful for developing ideas for experiments.
- Process diagrams are tools for visualizing steps in a process. They are useful in the formulation of research questions and the development of ideas for experiments.
- Thought experiments are used for evaluating hypotheses by exploring their logical implications. If an idea leads to paradoxes it is not generally applicable and may be discarded.
- The tools above are useful for generating, evaluating and ranking research hypotheses. When a clear research question has been stated the planning phase continues by identifying appropriate responses and useful factors, designing an experiment, determining factor ranges, and planning the data collection.
ANSWERS FOR EXERCISES
10.1 Experiment 1 is based on a new research question (Can insects use the Milky Way for orientation?), provides new data (on this particular beetle under specific conditions) and uses a new method (placing the beetles in a planetarium). Experiment 2 is based on a new research question (Do hot combustion products affect the lift-off length?), provides new data (lift-off lengths in a particular optical engine under specific conditions) and uses a new technique (comparing a symmetric with an asymmetric nozzle).
10.2-10.5 Left as exercises for the reader.
10.6 Here is one possible approach. Assume that the molecules in this breath are now evenly mixed in the atmosphere. First estimate the fraction of the atmosphere that these molecules make up. There is 105 kg air per square meter earth (the air pressure is 105 N/m2). The earth's diameter is 107 m (the circumference is, by definition, 40 000 km) and the surface area is roughly the diameter squared, or 1014 m2, giving us 1019 kg of air on earth. A breath is 10−3 m3 and the air density is 1 kg/m3, so Galileo's famous breath makes up the fraction 10−3/1019 = 10−22 of the earth's atmosphere. Hence, you must breath in 1022 molecules for one of these particular molecules to end up in your lungs. You currently hold 1−30 kg of air in your lungs with a molecular weight of 101 kg/kmol, amounting to 10−1 mol or roughly 1023 molecules. Amazingly, it is fair to assume that your lungs now contain some of the molecules he breathed out when (if) he uttered the famous words.
10.7 Here is one possible approach. A conservative guesstimate is that the water can cause caries if it has 1% of the sugar concentration of a commercial non-diet carbonated drink (about 10%). A quick internet search gives that the water flow of a moderately sized river is about 50 000 kg/s. To produce the required sugar concentration of 0.001 the factory must expel 50 kg/s of sugar. This amounts to 109 kg/year, which is at least one order of magnitude greater than the annual sugar production of a country like Sweden. The newspaper's hypothesis is not plausible.
10.8 Here is one approach. The reason that coffee appears dark is that it absorbs white light coming into the cup from the top. (The effect could potentially have been due to scattering instead of absorption, but then the liquid would appear white as milk.) When most photons are absorbed on their way from the surface to the coin and back, the coin is no longer visible. Dilution by a clear liquid will not change the total number of absorbing “coffee molecules” in the light path and thereby cannot render the coin visible again. The recipe is probably a joke made by someone who likes a strong cup of kaffekask.
References
1. Dacke, M., Nilsson, D.-E., Scholtz, C.H., et al. (2003) Animal Behaviour: Insect Orientation to Polarized Moonlight. Nature, 424, 33.
2. Dacke, M., Baird, E., Byrne, M., and Warrant, E.J. (2010) First Evidence of Star Orientation in Insects. Paper presented at: International Conference of Neuroethology, Salamanca, Spain.
3. Chartier, C., Aronsson, U., Andersson, Ö., et al. (2011) Influence of Jet-Jet Interactions on the Lift-Off Length in an Optical Heavy-Duty Diesel Engine. Submitted to Int J Engine Research.
4. Chartier, C. (2012) Spray Processes in Optical Diesel Engines: Air Entrainment and Emissions [Ph.D. thesis], Lund: Lund University.
5. Gamow, G. (1966) Thirty Years That Shook Physics: the Story of Quantum Theory, Doubleday & Co., New York.
6. Ishikawa, K. (1990) Introduction to Quality Control, Chapman & Hall, London.
7. Sagan, C. (1973) The Cosmic Connection: an Extraterrestrial Perspective, Dell Publishing, New York.
..................Content has been hidden....................
You can't read the all page of ebook, please click here login for view all page.