Scientific measurement

All experimental sciences rely on quantitative measurements of properties. Every measurement gives a numerical result that has three aspects a numerical magnitude an indicator of scale, called a unit and a precision. Each aspect is essential, and all three must be reported to make a measurement scientifically valuable. 

Uher G, Schebeske G, Barlow RG, Cummings DG, Mantoura RFC, Rapsomanikis SR, Andreae MO (2000) Distribution and air-sea gas exchange of dimethyl sulphide at the European western continental margin. Mar Chem 69 277-300 UNESCO (1994) Protocols for the Joint Global Ocean Flux Study (JGOFS). Core Measurements, Scientific committee on Oceanic Research Manual and Guides 29 170... 

Having surveyed some of the units used in chemistry, we now turn to techniques for handling numbers associated with measurements scientific notation and significant figures. 

Other series which have been produced by lARC are Information Bulletin on the Survey of Chemicals Being Tested for Carcinogenicity, Environmental Carcinogens. Methods of Analysis and Exposure Measurements, Scientific Publications and Technical Reports. 

It is also a fact that the biorefinery movement is by no small measure scientific in character. It is the prospect of taking raw biomass components and converting... 

As a scientific tool, ab initio quantum chemistry is not yet as accurate as modem laser spectroscopic measurements, for example. Moreover, it is difficult to estimate the accuracies with which various methods predict bond energies and lengths, excitation energies and the like. In the opinion of tlie author, chemists who... 

The CIF file format was quickly and widely adopted by the scientific community for at least two reasons [165J it was, and still is, endorsed by the lUCr and submission of data to the journal Acta Ciystallographka, Section C in a form conforming to CI F assures faster processing and hence faster publication of accepted papers. The current CIF file dictionary defines about 1200 data names, but it is still unable to represent all the details of the crystallographic measurements of macromolecules. Thus, yet another STAR-based data format is needed. 

According to an elegant remark by Davies [5], "Modem scientific data handling is multitechnique, multisystem, and manufacturer-independent, with results being processed remotely from the measuring apparatus. Indeed, data exchange and storage are steps of the utmost importance in the data acquisition pathway. The simplest way to store data is to define some special format (i.e., collection of rules) of a flat file. Naturally, one cannot overestimate the importance of databases, which are the subject of Chapter 5 in this book. Below we discuss three simple, yet efficient, data formats. 

Chemists frequently work with measurements that are very large or very small. A mole, for example, contains 602,213,670,000,000,000,000,000 particles, and some analytical techniques can detect as little as 0.000000000000001 g of a compound. For simplicity, we express these measurements using scientific notation thus, a mole contains 6.0221367 X 10 particles, and the stated mass is 1 X 10 g. Sometimes it is preferable to express measurements without the exponential term, replacing it with a prefix. A mass of 1 X 10 g is the same as 1 femtogram. Table 2.3 lists other common prefixes. 

Scientific Apparatus Makers Association 1140 Coimecticut Avenue, NW Washington, D.C. 20036 Standards for analytical instmments, laboratory apparatus, measurement and test instmments, nuclear instmments, optical instmments, process measurement and control, and scientific laboratory furniture and equipment (see Analytical methods). 

Metrologia International Committee of Weights and Measures (CIPM) Pavilion de Breteuil Parc de St. Cloud, Prance Includes articles on scientific metrology worldwide, improvements in measuring techniques and standards, definitions of units, and the activities of various bodies created by the International Metric Convention. 

Citation Searching. In the scholarly Hterature, authors cite earHer pubHcations that relate to the work being reported, thus a subject relationship exists between the citing and cited Hterature. This relationship has formed the basis for the Science Citation Index and related products, developed by the Institute for Scientific Information. Known as Scisearch in its on-line version, the Science Citation Index has become an important information retrieval tool in the second half of the twentieth century. It has been used for straightforward subject searching, in which mode it complements traditional indexed databases and indexes. It has also become a popular tool for hihliometric studies of various sorts, such as attempts to measure the relative impact of research carried out by different individuals or organizations, or the relative impact of pubHcations in different journals. 

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