Measurement mass and weight

See also Maps and Mapping Measurement and Units Quality Control Temperature Measurement Time Measurement Weight and Mass Measurement. 

All weight and mass measurements are relative and cannot be known as absolute values. The definition of standard weights and measures provides a reference framework in which units can be treated as though they are absolute measurements. 

Fascinating Facts About Weight and Mass Measurement... 

Mass is a measure of the quantity of material in a sample. We can measure that mass by its inertia —the resistance to change in its motion—or by its weight—the attraction of the sample to the earth. Since weight and mass are directly proportional as long as we stay on the surface of the earth, chemists often use the terms interchangeably. (Physicists do not do that.)... 

Density or specific gravity (relative density) is used whenever conversions must be made between mass (weight) and volume measurements. This property is often used in combination with other test results to predict oil quality, and several methods are available for measurement of density (or specific gravity). However, the density (specific gravity) (ASTM D1298 IP 160) is probably of... 

The primary air flow rate and moisture content of the fuel was given before each combustion run. Flue gas samples were taken continuously and the bed temperature was monitored on-line. The bed weight and mass loss rate were also continuously measured. 

The net quantity of contents (in terms of weight or mass, measure, or numerical count) shall be separately and accurately stated in a uniform location upon the principal display panel of that label, using the most appropriate units of both the customary inch/pound system of measure, as provided in paragraph (3) of this subsection, and, except as provided in paragraph (3)(A)(ii) or paragraph (6) of this subsection, the SI metric system ... 

A man wants to buy simvastatin tablets because he says he wants to keep his cholesterol down. On questioning he tells you he is 40 years old. His body mass index, which you calculate from the weight and height measurements he gives you, is 22. He says that he is worried about having a heart attack, because he has a high-powered and stressful job and his father, who was born in India, had a heart attack at the age of 56. He says he had an annual health check recently and that no problems were identified and his cholesterol level was 5.2 mmol/l, He is a non-smoker. 

Grotjahn L, Taylor LCE. The use of signal averaging techniques for the quantitation and mass measurement of high molecular weight compounds using fast atom bombardment mass spectrometry. Org Mass Spectrom. 1985 20 146 52. 

As an example demonstrating the effects of the chain architecture on chain dynamics, we here focus on the star-branched chain composed of monodisperse / arms. The top part of Figure 7 shows reduced moduli, [G ]r= (MG7CRT)c- and [G"]r = (M G"-(B>/s /GRT)c- o/ measured for dilute nine-arm star-branched polystyrene (PS) chains in theta solvents (decalin and dioctyl phthalate). These [G ]r and [G"]r data are plotted against a reduced frequency, orj. Here, M (= 5.0 x 10 ) and G are the molecular weight and mass concentration of the star-branched PS, respectively, is the solvent viscosity, R is the gas constant, T is the absolute temperature, and rj is the longest relaxation time (cf. eqn [54] shown later). The terminal relaxation tails of the [G ]r and [G"]r data (cf. eqn [30]) are dearly noted in Figure 7. 

Analytical chemists make a distinction between calibration and standardization. Calibration ensures that the equipment or instrument used to measure the signal is operating correctly by using a standard known to produce an exact signal. Balances, for example, are calibrated using a standard weight whose mass can be traced to the internationally accepted platinum-iridium prototype kilogram. 

Variations in the Force Due to Gravity. The mass of an object is the quantity of matter ia the object. It is a fundamental quantity that is fixed, and does not change with time, temperature, location, etc. The standard for mass is a platinum—iridium cylinder, called the International Kilogram, maintained at the International Bureau of Weights and Measures, ia Snvres, France. The mass of this cylinder is 1 kg by definition (9). AH national mass standards are traceable to this artifact standard. 

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