Lab Research Report 1: Procedures in the Physical Sciences

Ertugrul Alsan

Dr. Zahra Paraste Panah

05/05/2013
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SCI110

1. Astronomers use indirect methods to measure stellar distances. While triangulation and observation of parallax can be used for nearby stars, these methods fail for very distant galaxies and star systems. For these, astronomers use Cepheid variables – stars that change their luminosity in a known manner over precisely calculated intervals. If one Cepheid whose distance is known appears brighter than another whose distance is to be calculates, then the apparent magnitude and period of oscillation of the dimmer object can be used to calculate its distance relative to the brighter Cepheid (Freedman and Kaufmann, 2008, p. 638). In physics, mass of neutrinos is estimated indirectly through the phenomenon of neutrino oscillation. These particles are of three types – electron, muon and tau neutrinos – and they interchange (oscillate) between different types with mathematically defined probabilities. The mixture of neutrino types in a set of observations can be used to estimate upper and lower bounds on their mass values (Escrihulea, Tortola and Valle, 2011, p. 1). In chemistry lattice formation enthalpy is measured indirectly through the Born-Haber cycle. This is a stepwise calculation method in which a series of enthalpy changes is used to derive the final value. The lattice formation energy is deduced from the values of enthalpy of formation of each intermediate step (Kotz, Treichel and Townsend, 2012, p. 600).

2. Historically, one of the most important techniques has been the use of parallax to measure distance. Parallax is the apparent angular displacement of a distant object when it is observed from different positions using different lines of sight. The distance is calculated by measuring the subtended angle and the difference in positions from which the two observations are made. Parallax has been used by astronomers down the centuries to calculate distances to the moon, sun, planets and other heavenly objects (Hetherington, 2005, p. 1608). One of the most important tools has been the spectroscope. This instrument uses a prism, slit, diffraction grating or some other object to split light into component wavelengths. Scientists have used spectrometry to study characteristic emissions from many elements and compounds, and the spectrographs are used to determine the compositions of substances (Ball, 2001, p. 33).

3. A hazard associated with research in physical science is that of radiation while studying phenomena in nuclear physics. In fact Marie Curie was afflicted with leukemia from her prolonged exposure to radium and other radioactive substances. Today physicists and technicians who work in nuclear plants and with medical radiology equipment wear clothing that protects them in terms of time, distance and shielding effects. Protective gear includes gloves, overalls, shoe covers and fume hoods having activated charcoal air filters. For working with radioiodine, two pairs of gloves should be worn since the substance can penetrate through the outer layer (Shapiro, 2002, p. 354). Standard full-body protective suits are usually designed to work in areas containing dry contaminants at a concentration level not exceeding 1700 Bq per 100 sq. cm. (Prince, 2012, p. 214).

4. There are many ways in which safety of the global community can be affected by advances in genetics and material technology. Genetically Modified (GM) crops are being introduced for human consumption by many corporations, but their impact on the food chain as well as on the environment in general has not yet been fully assessed. GM crops are usually designed to have antifungal and antibacterial properties, high tolerance to insecticides and resistance to insects. But they may have unintended effects on other organisms. For example it was shown that pollen from a strain of modified corn induced high mortality among monarch butterfly larvae (Losey, 1999, p. 214). Some other GM plants have been shown to be harmful towards bees. Similarly, a wide range of nano materials are being used in many products, including construction materials, fabrics, medicine, sensors etc. While these products have significantly enhanced material properties, their effects on human health are yet to be studied. Recent studied indicate that nano materials should be confined in such a way that they are not released to the environment, because they can easily breach the human skin and reach internal organs (Yokel and McPhail, 2011, p. 4). Thus, for both GM food and nano technology it is essential to conduct many more tests on their environmental impact before they are made widely available to the global community.

References

Ball, D. W. (2001). The Basics of Spectroscopy. Washington: The International Society for Optical Engineering.

Escrihulea, F. J., Tortola, M. and Valle, J. W. F. (2011). Global constraints on muon-neutrino nonstandard interactions. Phys. Rev. D, 83(9), 093002.

Hetherington, N. S. (2005). Parallax. In The Oxford Guide to the History of Physics and Astronomy. (Vol. 10, pp. 243-244). Oxford: Oxford University Press.

Freedman, R. A. and Kaufmann, W. J. (2008). Universe, 8th Ed. New York: W. H. Freeman and Company.

Kotz, J. C., Treichel, P. M. and Townsend, J. R. (2012). Chemistry & Chemical Reactivity, 8th Ed. California: Brooks-Cole, Cengage Learning.

Losey, J. E., Rayor, L. S. and Cater, M. E. (1999). Transgenic pollen harms monarch larvae. Nature, 399. 214.

Prince, R. (2012). Radiation Protection at Light Water Reactors. Berlin: Springer-Verlag.

Shapiro, J. (2002). Radiation Protection: A Guide for Scientists, Regulators, and Physicians. London: Harvard University Press.

Yokel, R. A. and McPhail, R. C. (2011). Engineered Nano Materials: Exposures, Hazards and Risk Prevention. J. Occup. Med. Toxicol., 6, 7-34.