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Just-noticeable difference. In the branch of experimental psychology focused on sense, sensation, and perception, which is called psychophysics, a just-noticeable difference or JND is the amount something must be changed in order for a difference to be noticeable, detectable at least half the time. [1]
Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions. [1] Temperature is a monotonic function of the average molecular kinetic energy of a substance.
Yield (chemistry) In chemistry, yield, also referred to as reaction yield, is a measure of the quantity of moles of a product formed in relation to the reactant consumed, obtained in a chemical reaction, usually expressed as a percentage. [1] Yield is one of the primary factors that scientists must consider in organic and inorganic chemical ...
Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations Na + and hydroxide anions OH −. Sodium hydroxide is a highly corrosive base and alkali that decomposes lipids and proteins at ambient temperatures and may cause severe chemical ...
Atomic ratio. The atomic ratio is a measure of the ratio of atoms of one kind (i) to another kind (j). A closely related concept is the atomic percent (or at.% ), which gives the percentage of one kind of atom relative to the total number of atoms. [1] The molecular equivalents of these concepts are the molar fraction, or molar percent .
In general, the term "percentage point(s)" indicates an absolute change or difference of percentages, while the percent sign or the word "percentage" refers to the relative change or difference. Examples Comparisons. Car M costs $50,000 and car L costs $40,000. We wish to compare these costs.
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula SiO 2, commonly found in nature as quartz. In many parts of the world, silica is the major constituent of sand. Silica is abundant as it comprises several minerals and synthetic products. All forms are white or colorless, although impure samples can be colored.
Accuracy is how close a given set of measurements ( observations or readings) are to their true value . Precision is how close the measurements are to each other. In other words: Precision is a description of random errors (a measure of statistical variability ). Accuracy has two definitions, per ISO [1]: