The Science of Measurement

The quality of a measure is determined by its reliability and validity. No measure is perfect, and all measures have limitations on their reliability and validity. 

It is very unlikely that this distribution represents the rods produced by the machine. The explanation has to lie in the behavior of the inspector. If too many rods are rejected, people might lose their job, or worse yet, the plant might close. Surely there will be no problem, thinks the inspector, if we list this. 999 rod at 1.000. 

Reliability is not a property of the instruments, but of the entire measurement process. This includes the tools, the instruments, the procedures, and the people. Subjective judgment can be very reliable in some 

The level of reliability of a measure limits the kinds of decisions that should be based on that measure. A good case in point is the financial statements of public companies. There has been considerable recent publicity about the lack of reliability of these statements. Emon statements showed dazzling profits as the company was plunging into bankruptcy. Based on the statements, people and institutions invested large amonnts of money in Emon stock. 

Although Enron is an extreme case, there is considerable limitation on the reliability of financial statements even from ethical companies. If we assign two independent teams of accountants to a company, it is likely that they would produce significantly different numbers. 

To make full use of the capabilities provided by SIMS, an understanding of the principles and practices commonly used in data collection is desirable. As with most micro-analytical techniques, two aspects make for a good result, these being the optimization of the analysis conditions to the signals of interest and pairing the instrumentation to the analysis need. 

As with many techniques, optimization of the analytical conditions to the job at hand can be considered the art of measurement. Common aspects associated with the art of measurement pertinent to SIMS are covered in Chapter 5. 

Secondary Ion Mass Spectrometry An Introduction to Principles and Practices, First Edition. Paul van der Heide. 

---

Thermometry is the science of measuring the temperature of a system or the ability of a system to transfer heat to emother system. Temperature mecisurement is important to a wide range of activities, including manufacturing, scientific research, and medical practice. Thermometry relates to the dilatrometric measurement in that the expansion of a gas, liquid or solid is used to determine temperature. 

The BERM symposia have served further to clarify understanding of the basic attributes of a good reference standard that is indispensable for establishing new frontiers in the science of measurements, and to highlight the invaluable infrastructure and proven record of metrological excellence available at the National Measurement Institutes to accomplish such tasks. 

Standards are now used everywhere to demonstrate reliability. Standards have replaced good trust in reputations. Psychology, the relation of human understanding, has been replaced by the science of measurements. 

In chemical work, it is important to be able to calculate how much raw material is needed to prepare a certain quantity of products. It is also useful to know if a certain reaction method can prepare more product from a given quantity of material than another reaction method. Analyzing materials means finding out how much of each element is present. To do the measurements, we often convert parts of the material to compounds that are easy to separate, and we then measure those compounds. All these measurements involve chemical stoichiometry, the science of measuring how much of one thing can be produced from certain amounts of others. 

Stoichiometry the science of measuring how much of one substance can be produced from given quantities of others. 

Starting with the ISO definition of metrology metrology is the science of measurement. 

National Institute of Standards and Technology. Nanotechnology is BIG at NIST. Available online. URL http //www.nist.gov/public affairs/nanotech.htm. Accessed May 28, 2009. NIST is a federal agency devoted to aiding innovation and industrial output by advancing the science of measurement and providing accurate standards by which such measurements can be made. Work at the NIST laboratory involves atomic and molecular devices and other aspects of nanotechnology, as described on this Web site. 

These chapters contain specific information about the principles of assays defined in the text and contain what may well be the most comprehensive guide to the science of measurement in the scientific literature. Both the NF and the Nutritional Supplements have their own general chapters. Guidelines to Good Manufacturing practices are supplied, with guidance to small-scale pharmaceutical operations such as those encountered in a typical dispensing pharmacy. 

Metrology is the science of measurements and one of today s key sciences. It is of fundamental importance in industry and trade, but also in the environmental, consumer, and health protection beld. The Bureau International des Poids et Mesures (BIPM) was set up by the Convention of the Metre (Fig. 7.1). The task of the BIPM is to provide worldwide uniformity of measurements and their trace-ability to the International System of Units (SI), the basis for a coherent common... 

The concept of stoichiometry was first described in 1792 by the German scientist Jeremias Benjamin Richter (1762-1807). He stated that "stoichiometry is the science of measuring the quantitative proportions or mass ratios in which chemical elements stand to one another." Can you think of another reason why Richter was famous ... 

Calorimetry the science of measuring heat flow. (9.4) Capillary action the spontaneous rising of a liquid in a narrow tube. (16.2)... 

Several techniques have been devised for measuring fat and its distribution in living humans. Terms used to refer to fat s distribution include subcutaneous fat, visceral fat, android (male type) obesity, and gynoid (female type) obesity. The science of measurement of body size, weight, and proportions is called anthropometry. Hence, the following techniques are methods of anthropometry. 

Prior to the advent of sophisticated mechanical and electrical instrumentation, the observation of thermal phenomena was restricted to systems which were amenable to detection by the human senses. Such observations included investigations of boiling or melting processes, sublimation, fractional crystallization, color changes and the occurrence of odors. With the invention of the thermometer, the first quantitative experiment was made possible. Development of thermometry led to "thermal analysis by recording the temperature of a test material as a function of time. Further developments led to calorimetry — the science of measuring quantities of heat. 

Sensory is the science of measurement with the human senses. Panelists measure subjective and individually to produce an only one objective final result. Mention of the human senses normally brings to mind the usual 5 senses, smell, taste, vision, hearing and touch. In both the sensory and the physiological sense we better speak of the modalities sense of smell, sense of taste, sense of seeing, sense of hearing and sense of touch (tactile or haptic sense). 

Patient satisfaction is a commonly used measure to help assess how well healthcare providers are meeting the needs of their patients. Donebedian states that satisfying patients is one important indicator of quality care, because it demonstrates the ability of the provider to meet expectations and values of the patient. Industry reports on managed care organizations include patient satisfaction as one measure of service quality.However, the science of measuring patient satisfaction is yet in its infancy. 

Chemistry, like all sciences, relies on measurement, yet a poll of our students and colleagues showed that few could even start to give a reasonable explanation of measurement. Reading textbooks on data analysis revealed that this most basic act of science is rarely defined. Believe it or not there are people that specialize in the science of measurement a field of study called metrology. The definition used in this book for measurement is a set of operations having the object of determining the value of a quantity. We will come back to this but first... 

The science of measuring ocean depths to determine the topography of the sea floor, benthic organism (benthos)... 

But quantities are often determined indirectly as well, meaning they are found by calculation from other measured quantities. In the field of geodesy, the science of measuring and mapping the Earth s surface, lengths and altitudes have mostly been determined through calculations based on measured angles (Fig. 1.3). When he... 

Calorimetry is the science of measuring heat flow. It is the primary way that we determine changes in the energy of systems. 

Calorimetry is the science of measuring heat changes from chemical reactions and physical events. DSC is described in Section 16.3 and has been a staple method of analysis for materials scientists. Classical DSC instruments and classical calorimetric titrimetry instruments (Sections 16.5 and 16.6) often lack the sensitivity required for the study of biological samples, where processes like the folding or unfolding of a protein may exchange only microjoules of heat. A new class of ultrasensitive microcalorimetry instrumentation has been developed primarily for studies in the life sciences, where sample amounts may be extranely limited. 

Metrology, n. (from greek metron (measure), and -logy) is the science of measurement. Metrology includes all theoretical and practical aspects of measurement. It is a field of study which has been highly... 

Stoichiometry is the science of measuring the quantitative proportions or mass ratios in which chemical elements stand to one another. ... 

Applied Chemistry, and others). The VIM is mainly focused on basic expressions in metrology, the science of measurements. As the core subject of analytical chemistry and isotopic analysis is measurements, they belong to metrology and, consequently, the metrological terminology should be used. 

---