Weight metric measures

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. 

An accurate statement of the weight or measure of each component, using the same weight system (metric, avoirdupois, or apothecary) for each component. Reasonable variations may be permitted, however, in the amount of components necessary for the preparation in the dosage form, provided they... 

Most of the problems in this book use the English measures of length, volume, and weight. But metric measures are very important to know, because of the great incidence of foreign travel and trade with other countries that use metrics. 

Lavoisier began to feel his own insecurity he was personally attacked in pamphlets. Gradually he withdrew from his public offices, giving his attention more completely to the work of the commission of weights and measures, then laboring with the determination of the standards of the metric system. 

In 1960 the International General Conference on Weights and Measures adopted an improved form of the metric system, The International System of Units (SI). The units of mass, length, and time are the kilogram (kg), meter (m), and second (s). The following prefixes are used for fractions and multiples ... 

SI (Systeme International, International System of Units)—metric-based system of weights and measures adopted in 1960 by the 11th General Conference on Weights and Measures, in which 36 countries, including the U.S., participated. SI consists of seven basic units ... 

The metric system of weights and measures is used by scientists of all fields, including chemists. This system uses the base 10 for measurements for conversions, measurements may be multiplied or divided by 10. Table 2.1 lists the most frequently used factors in the laboratory which are based on powers of 10. 

The filtrate was evaporated to dryness on the water bath. The fractions were, in individual cases, examined chemically and spectrophoto-metrically, and their molecular weights were measured by gel-permeation chromatography. 

Temperature. Temperature was not one of the original properties that the French academy deemed necessary to include in the metric system. In fact, as late as 1921, members of the 6th General Conference of the International System of Weights and Measures were still objecting to the inclusion of measurements (other than length and mass) seemingly for no other reason other than to keep the base units pure. ... 

The original idea of the metric system was that either approach would provide the same unit of metric volume. Unfortunately, it did not work because of the subtle differences in density caused by subtle differences in temperature. Thus, the kilogram-based milliliter equaled 1.000,027 cubic centimeters. Because of the discrepancy, the International System for Weights and Measures had to make a choice between which approach would be accepted to obtain volume measurements, and the nod was eventually given to the cubic length technique. The use of liters and milliliters in volumetric ware is therefore misleading because the unit of volume measurement should be cubic meters (cubic centimeters are used as a convenience for smaller containers). The International System of Units (SI) and the ASTM accept the use of liters and milliliters in their reports, provided that the precision of the material does not warrant cubic centimeters. Because the actual difference in one cubic centimeter is less than 3 parts in 100,000, for most work it is safe to assume that 1 cm3 is equal to 1 mL. 

The current International System of Units (SI) is a metric system of measurement which has been adopted internationally by the General Conference of Weights and Measures and is described in an International Standard... 

For some readers (especially Americans), the metric system (other wise known as the SI system) is vague, or somewhat unfamiliar. 99% of all the units of weight and measurement in this book are given using the SI system therefore, a translation from one unit to another may be needed for some to fully interpret the quantities. As most people are probably aware however, most laboratory equipment is automatically calibrated in SI units, so even inexperienced persons will not have to worry too much about knowing the SI system. Regardless, try a few conversions of your own just for practice. Example Convert 150 Celsius into Fahrenheit—Solution multiply 150 by 1.8 and then add 32. The answer would be 302 Fahrenheit. Example 2 Convert 1.2 gallons into milliliters—Solution multiply 1.2 by 3,785. The answer would be 4542 milliliters. 

Several aspects of measurement will be considered in this chapter. First, Section 2.1 presents the factor label method, which makes calculations with measured quantities easier. This method will be used in the sections that follow and throughout the book. Next, in Section 2.2, we consider how to calculate with extremely large and extremely small numbers, using exponential notation. Section 2.3 introduces the metric system, a system of weights and measures... 

The meter is the primary unit of length in the metric system. Its abbreviation is m. The meter is defined in such a way that it can be duplicated precisely in any well-equipped laboratory in the world. It had been defined as the distance between two marks on a metal bar kept at the Bureau of Weights and Measures in Paris. (It now has an even more precise definition.) A meter is 39.37 in. long—3.37 in. longer than a yard. 

The metric system was initially spread to other European countries in the wake of Napoleon s conquests, but did not start to became common coin for scientific and technological work until after the meeting of The General Conference on Weights and Measures in Paris in 1960 (boy, does that sound like a fun conference). 

SI is somewhat different than the CGS system, in use for many years, which has often been called the Metric System. SI is a system adopted internationally by the General Conference of Weights and Measures. Among some of the principles are the use of the kilogram for mass only, and the use of newton for force or weight. 

The relationships between the customary units are not as systematic as the relationships between units in the metric system. Here, lengths are measured in inches, feet, yards, and miles. Weights are measured in pounds and ounces. And volumes are measured in cubic inches, cubic feet, and so forth. Below is a chart of common conversions for customary units. 

The Metric System of weights and measures is used in science. For a brief outline of the system, with tables, see Appendix A, i8. 

The relation of the metric system to the weights and measures in common use is shown by the following —... 

Brix is the percentage by weight of the solids in a pure sucrose solution. By general acceptance, the Brix represents the apparent solids in a sugar solution as determined by the Brix hydrometer or other densi-metric measurement converted to the Brix scale. 

At the time that the metric system was set up, in 1799, it was intended that the milliliter be exactly equal to the cubic centimeter (cm ). However, it was later found that the relation between the gram, as given by the prototype kilogram, and the centimeter, one one-hundredth of the distance between two engraved lines on a standard platinum-iridium bar, the prototype meter kept in Paris hy the International Bureau of Weights and Measures, is such that the milliliter is not exactly equal to the cubic centimeter, but is instead equal to [.000027 cm . It is obvious that the distinction between ml and cm is ordinarily unimportant. 

Eventually, ancient rules of thumb gave way to more carefully defined units. The metric system was adopted in France in 1799 and the British Imperial System of units was established in 1824. In 1893, the English units used in the United States were redefined in terms of their metric equivalents the yard was defined as 0.9144 meter, and so on. But English units continue to be used in the United States to this day, even though the Omnibus Trade and Competitiveness Act of 1988 stated that it is the declared policy of the United States...to designate the metric system of measurement as the preferred system of weights and measures for United States trade and commerce. ... 

The General Conference on Weights and Measures updated the metric system in 1960 and renamed it the International System of Measurements. The system is commonly referred to as SI, which is short for the French name, Le Systeme International d Unites. Scientists from all around the world have adopted SI, and there has been a push in many countries to convert the general population to the SI units. 

Another thing that American students might find interesting is that the units liter and milliliter are absent. When the General Conference on Weights and Measures updated the metric system in 1960, they eliminated the liter This means that the only metric unit that we have really embraced in this country is the one that was declared outdated more than 40 years ago ... 

The minimum quantity of food in the container or wrapper, expressed in terms either of net weight or measure in metric units, should be declared, although non-metric units may also be shown. 

Rehydration ratio was measured as previously described. Bulk density was determined as weight per voJ-ume basis (11). Carotene contents were determined by solvent extraction and spectrophoto-metric measurements (30). The amount of carotene loss was calculated according to the established formula (31). 

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