Naked eye observations

By naked eye observation, one could see colour changes at the anode (yellow) and cathode (white). Also bubbles (H2) could be seen at the cathode and caseation (i.e., yellowish precipitate, no doubt due to the action of chlorine) at the anode. The anode area appeared congested (dry, compact)... 

Probably the first modern reference to meteorite thermoluminescence is that of Herschel (1), although it is possible that the luminescence observed by Howard after passing an electric charge "from 34 square feet of glass" across the Siena meteorite could, in part, have been TL (2). Herschel reported naked eye observations of the TL produced by dust from the Middlesbrough meteorite as it was sprinkled on a hotplate, and he suggested, correctly, that the luminescent component was feldspar. 

Constrained as it is in an orbit close to the Sun, Mercury is not an easy planet for naked-eye observers to locate. The greatest separation between the planet and the Sun, as seen from Eartb, is 28° and consequently the planet is never visible against a truly dark slg. Even at its greatest angular separation from the Sun, Mercury will either set within two hours of sunset, or rise no earlier than two hours before the Sun. Nonetheless, Mercury has been known since the most ancient of times, with observations of the planet being reported as far back as several centuries b.c. The Greek philosopher Plato refers to the distinctive yellow color of Mercury in Book X of his Republic,... 

Phenomenology of corrosion for metals and polymer materials is not the same. For example, the terms such as corrosion rate, pitting, end grain attack, and intergranular attackusQd to describe metals behaviors are not applicable to plastics. Not only are the terms for plastics different blistering, discoloration, cracking, etc.) but they are based on a naked-eye observation and not at a microscopic level as for metals. 

In the current study, these discrimination functions were utilized to finally determine the meso-compositions in the granite image shown in Figure 1. The estimations of the minerals agree well with the naked-eye observations based on the combination of color, luster, cleavage, hardness. The correctness is 100%. 

Among the main advantages of colorimetric sensing is the easy and widely available instrumentation. The oldest and still perfectly viable method of colorimetric sensing is an old-fashioned naked-eye observation. There are hundreds of examples of dipstick -type sensors, vide infra. The most widely used method for data collection is UV-vis absorption spectroscopy. Similarly, some multiwell plate readers comprise a polychromatic light source and a CCD camera similar to common diode-array spectrophotometers and are also capable of recording the whole spectra from each well. One assumes that the above methods of data acquisition need not be discussed in detail. 

In addition to elastic turbulence (characterised by helical deformation) another phenomenon known as sharkskin may be observed. This consists of a number of ridges transverse to the extrusion direction which are often just barely discernible to the naked eye. These often appear at lower shear rates than the critical shear rate for elastic turbulence and seem more related to the linear extrudate output rate, suggesting that the phenomenon may be due to some form of slip-stick at the die exit. It appears to be temperature dependent (in a complex manner) and is worse with polymers of narrow molecular weight distribution. 

This transitory behavior was observed to arise from all the weathering agents considered in this study except ozone. Instead, test coupons exposed to ozone exhibited an initial decline in the crosslink density of the silicone with the formation of surface cracks, which were difficult to distinguish with the naked eye. With continued exposure to ozone, however, the material would begin to crosslink. We proposed that ozone s greatest affinity... 

Solids tend to crystallize in definite geometric forms that often can be seen by the naked eye. In ordinary table salt, cubic crystals of NaCl are clearly visible. Large, beautifully formed crystals of such minerals as fluorite, CaF2, are found in nature. It is possible to observe distinct crystal forms of many metals under a microscope. 

Droplets of various hquids were prepared in several ways. For example, a macroscopic drop was first deposited on the substrate and then absorbed from an edge using filter paper. In other cases a macroscopic drop was blown away with a jet of N2 or air. These processes leave a surface that appears dry to the naked eye but still contains many tiny droplets that can be observed with SPFM. If the droplets are of aqueous solutions, the water vapor pressure in the chamber, with which they readily equilibrate, determines their size. For hquids with low vapor pressure, films and droplets can be formed by condensation from a warmed reservoir. 

Gold is irregular in shape with 0.01 to 1 mm in size. Some of gold grains can often be observed by naked eyes. 

Using this equation an attempt was made to find a critical Re-number which could be correlated to the onset of vortices observed with the naked eye, as has been done, for example, for Newtonian fluids [93], but no correlation could be found [88]. The reason is probably due to the fact that polymer solutions are viscoelastic fluids, also called second-order fluids. 

Diffusion is the process by which solute molecules are transported from one part of a system to another as a result of random molecular motion [2], It can be observed with the naked eye when a drop of dye is carefully and slowly placed at the bottom of a beaker filled with water. At first the colored part is separated from the clear by a sharp, well-defined boundary. Later the upper part turns colored, and the color becomes fainter toward the top while the lower part becomes correspondingly less intensely colored. After sufficient time, the whole solution has a uniform color. There is evidently, therefore, a net transfer of dye molecules from the lower part to the upper part of the beaker. The dye molecules have diffused into the water. This diffusion process is primarily due to random molecular motion. 

Experiment 3 In general, sonoluminescence emission is not discemable with the naked eye. The luminosity of the secondary emission from luminol (oxidised by sonochemically produced OH radicals) however, is several orders of magnitude brighter and is easily seen in a dark room. Prepare a 0.1 mM aqueous luminol solution in 0.1 M NaOH. Sonicate this solution and observe the emission pattern. This will appear as bands of light and dark if a standing wave reactor is used or in more elaborate forms in different reactors. If a 20 kHz horn is used, a cone shaped zone of luminescence will be observed. Explain the emission pattern. 

A positive evidence for a dirty apparatus may be sought by observing the adherence of droplets to the walls of a burette or pipette. However, in a clean volumetric apparatus, the liquid drains down quite uniformly thereby wetting the walls so that no droplets are visible to the naked eye. 

Microbe An organism which cannot be observed with the naked eye e. g. unicellular animals, lower algae, lower fungi, bacteria. [NIH]... 

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