Color change, description

Quantitative data involves a number, and qualitative data does not. Qualitative data may be a description such as a slight/moderate/intense color change or a weak/strong/explosive reaction or it may simply be the absence/presence of an event. 

Time Exposed (h) Color Change° Munsell Color Description... 

Color Change. Tables I through IV summarize the color change data, obtained by comparison with an untreated/unexposed control sample, for the dyed cotton and wool fabrics exposed to CC14, dichlorvos, petroleum distillate, and boric acid respectively. Each table reports the total color difference at 4, 8, and 160 weeks duration after initial treatment. Also reported is a visual description of the perceived color change from the untreated control after 160 weeks. 

In order to determine the equivalence point (the point at which exactly stoichiometric quantities of sample and titrant have been brought together), it is necessary to find a chemical or physical property that changes very rapidly at this point. Many properties have been used successfully, but the most common method is the visual observation of a color change in a chemical indicator present in very small concentration. This observable change takes place at the end point, which must lie very close to the equivalence point. The technique of titration is concerned principally with approaching the end point with reasonable speed without running over it is best learned by practice, but there are descriptions in the literature that may be helpful. 

In most experiments, scientists collect quantitative data, which are data that can be measured with instruments. Quantitative data involves numbers and measurements against a standard. Those measurements may be taken at specified time intervals. They also collect qualitative data, descriptive information from observations other than measurements. Qualitative data includes any observations made with the senses of hearing or seeing such as a popping sound or a color change. 

The indirect methods discussed thus far have dealt with measurement of color only as it can be correlated with physical characteristics of materials and the effect of these materials on radiant energy. As has been pointed out, the reflectance spectro-photometric curve describes a property of the material. A change in the reflectance spectrophotometric properties may not always result in a change in visual color. The reason is that color of the object is not an unchangeable characteristic of the object itself, dependent only upon these reflectance properties, but is also dependent upon the quality of the illuminating light and the sensitivity of the observer s eye. Thus the measurement and description of visual color are psychophysical problems... 

It is interesting to notice that the three pressure surfaces in Figure 7 form a characteristic swallowtail structure. As one could see, the appearance of this structure is directly related to the fact that the phase transition between color superconducting and normal quark matter, which is driven by changing parameter //,. is of first order. In fact, one should expect the appearance of a similar swallowtail structure also in a self-consistent description of the hadron-quark phase transition. Such a description, however, is not available yet. 

While not true CD, a novel telluriding agent, Te dissolved in an alkaline solution of hydroxymethanesulphinic acid, has been used to convert Cd(OH)2 films to CdTe [21]. While there is some doubt as to the nature of the active telluriding agent, from the description of the preparation process of this reagent— a change in color from deep purple (characteristic of polytelluride ions, TeJ ) to a faint pink (pure Te is colorless but will be colored this way if traces of TeJ are present) as the preparation proceeds—it does appear to contain free teUuride ion. It should be noted that elemental Te can slowly dissolve in concentrated air-free alkaline solutions, with the formation of polytelluride and its characteristic purple color. 

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