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Meniscus (liquid)
In physics (particularly liquid statics), the meniscus (: menisci, ) is the curve in the upper surface of a liquid close to the surface of the container or another object, produced by surface tension. A concave meniscus occurs when the attraction between the particles of the liquid and the container ( adhesion) is more than half the attraction of the particles of the liquid to each other ( cohesion), causing the liquid to climb the walls of the container (see ). This occurs between water and glass. Water-based fluids like sap, honey, and milk also have a concave meniscus in glass or other wettable containers. Conversely, a convex meniscus occurs when the adhesion energy is less than half the cohesion energy. Convex menisci occur, for example, between mercury and glass in barometers and thermometers. In general, the shape of the surface of a liquid can be complex. For a sufficiently narrow tube with circular cross-section, the shape of the meniscus will approximate a sectio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reading The Meniscus
Reading is the process of taking in the sense or meaning of symbols, often specifically those of a written language, by means of Visual perception, sight or Somatosensory system, touch. For educators and researchers, reading is a multifaceted process involving such areas as word recognition, orthography (spelling), Alphabetic principle, alphabetics, phonics, phonemic awareness, vocabulary, comprehension, fluency, and motivation. Other types of reading and writing, such as pictograms (e.g., a hazard symbol and an emoji), are not based on speech-based writing systems. The common link is the interpretation of symbols to extract the meaning from the visual notations or tactile signals (as in the case of braille). Overview Reading is generally an individual activity, done silently, although on occasion a person reads out loud for other listeners; or reads aloud for one's own use, for better comprehension. Before the reintroduction of Palaeography, separated text (spaces betwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermometer
A thermometer is a device that measures temperature (the hotness or coldness of an object) or temperature gradient (the rates of change of temperature in space). A thermometer has two important elements: (1) a temperature sensor (e.g. the bulb of a mercury-in-glass thermometer or the pyrometric sensor in an infrared thermometer) in which some change occurs with a change in temperature; and (2) some means of converting this change into a numerical value (e.g. the visible scale that is marked on a mercury-in-glass thermometer or the digital readout on an infrared model). Thermometers are widely used in technology and industry to monitor processes, in meteorology, in medicine (''medical thermometer''), and in scientific research. A standard scale While an individual thermometer is able to measure degrees of hotness, the readings on two thermometers cannot be compared unless they conform to an agreed scale. Today there is an absolute thermodynamic temperature scale. Internat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capillary Action
Capillary action (sometimes called capillarity, capillary motion, capillary rise, capillary effect, or wicking) is the process of a liquid flowing in a narrow space without the assistance of external forces like Gravitation, gravity. The effect can be seen in the drawing up of liquids between the hairs of a paint-brush, in a thin tube such as a Drinking straw, straw, in porous materials such as paper and plaster, in some non-porous materials such as clay and liquefied carbon fiber, or in a biological cell. It occurs because of intermolecular forces between the liquid and surrounding solid surfaces. If the diameter of the tube is sufficiently small, then the combination of surface tension (which is caused by Cohesion (chemistry), cohesion within the liquid) and Adhesion, adhesive forces between the liquid and container wall act to propel the liquid. Etymology Capillary comes from the Latin word capillaris, meaning "of or resembling hair". The meaning stems from the tiny, hairl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parallax
Parallax is a displacement or difference in the apparent position of an object viewed along two different sightline, lines of sight and is measured by the angle or half-angle of inclination between those two lines. Due to perspective (graphical), foreshortening, nearby objects show a larger parallax than farther objects, so parallax can be used to determine distances. To measure large distances, such as the distance of a planet or a star from Earth, astronomers use the principle of parallax. Here, the term ''Stellar parallax, parallax'' is the semi-angle of inclination between two sight-lines to the star, as observed when Earth is on opposite sides of the Sun in its orbit. These distances form the lowest rung of what is called "the cosmic distance ladder", the first in a succession of methods by which astronomers determine the distances to celestial objects, serving as a basis for other distance measurements in astronomy forming the higher rungs of the ladder. Because parallax ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Level Device
A water level ( '' lfadolasticho') is a siphon utilizing two or more parts of the liquid water surface to establish a local horizontal line or plane of reference. It is used to determine the apparent inclination of an object or surface and for matching water level elevations at locations that are too far apart for a spirit level to span. The simplest water level is a section of clear tubing, partially filled with water. Water is easily procured for use, and easily discarded after use. The ends are held vertical, and the rest of the tubing lies on the ground or floor. The water level at each end of the tube will be at the same elevation, whether the two ends are adjacent or far apart, so a line between them will be horizontal at its midpoint and a shed base, building foundation or similar structure laid out using several such lines will be "horizontal" within building tolerances on any scale over which use of a water level is practicable. Water levels have been used for many year ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meniscus
Meniscus may refer to: *Meniscus (anatomy), crescent-shaped fibrocartilaginous structure that partly divides a joint cavity *Meniscus (liquid) In physics (particularly liquid statics), the meniscus (: menisci, ) is the curve in the upper surface of a liquid close to the surface of the container or another object, produced by surface tension. A concave meniscus occurs when the attract ..., a curve in the upper surface of liquid contained in an object * Meniscus (optics), a type of optical lens * ''Meniscus'' (bacterium), a genus of bacteria See also * * {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilhelmy Plate
A Wilhelmy plate is a thin plate that is used to measure equilibrium surface or interfacial tension at an air–liquid or liquid–liquid interface. In this method, the plate is oriented perpendicular to the interface, and the force exerted on it is measured. Based on the work of Ludwig Wilhelmy, this method finds wide use in the preparation and monitoring of Langmuir films. Detailed description The Wilhelmy plate consists of a thin plate usually on the order of a few square centimeters in area. The plate is often made from filter paper, glass or platinum which may be roughened to ensure complete wetting. In fact, the results of the experiment do not depend on the material used, as long as the material is wetted by the liquid. The plate is cleaned thoroughly and attached to a balance with a thin metal wire. The force on the plate due to wetting is measured using a tensiometer or microbalance and used to calculate the surface tension (\gamma) using the Wilhelmy equation: :\ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contact Angle
The contact angle (symbol ) is the angle between a liquid surface and a solid surface where they meet. More specifically, it is the angle between the surface tangent on the liquid–vapor interface and the tangent on the solid–liquid interface at their intersection. It quantifies the '' wettability'' of a solid surface by a liquid via the Young equation. A given system of solid, liquid, and vapor at a given temperature and pressure has a unique equilibrium contact angle. However, in practice a dynamic phenomenon of contact angle hysteresis is often observed, ranging from the advancing (maximal) contact angle to the receding (minimal) contact angle. The equilibrium contact is within those values, and can be calculated from them. The equilibrium contact angle reflects the relative strength of the liquid, solid, and vapour molecular interaction. The contact angle depends upon the medium above the free surface of the liquid, and the nature of the liquid and solid in contact. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamic Contact Angle Attension Sigma
Dynamics (from Greek δυναμικός ''dynamikos'' "powerful", from δύναμις ''dynamis'' "power") or dynamic may refer to: Physics and engineering * Dynamics (mechanics), the study of forces and their effect on motion Brands and enterprises * Dynamic (record label), an Italian record label in Genoa Mathematics * Dynamical system, a concept describing a point's time dependency ** Topological dynamics, the study of dynamical systems from the viewpoint of general topology * Symbolic dynamics, a method to model dynamical systems Social science * Group dynamics, the study of social group processes especially * Population dynamics, in life sciences, the changes in the composition of a population * Psychodynamics, the study of psychological forces driving human behavior * Social dynamics, the ability of a society to react to changes * Spiral Dynamics, a social development theory Other uses * Dynamics (music), the softness or loudness of a sound or note * DTA Dynamic, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spherical Surface
A sphere (from Greek , ) is a surface analogous to the circle, a curve. In solid geometry, a sphere is the set of points that are all at the same distance from a given point in three-dimensional space.. That given point is the ''center'' of the sphere, and the distance is the sphere's ''radius''. The earliest known mentions of spheres appear in the work of the ancient Greek mathematicians. The sphere is a fundamental surface in many fields of mathematics. Spheres and nearly-spherical shapes also appear in nature and industry. Bubbles such as soap bubbles take a spherical shape in equilibrium. The Earth is often approximated as a sphere in geography, and the celestial sphere is an important concept in astronomy. Manufactured items including pressure vessels and most curved mirrors and lenses are based on spheres. Spheres roll smoothly in any direction, so most balls used in sports and toys are spherical, as are ball bearings. Basic terminology As mentioned earlier is t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barometer
A barometer is a scientific instrument that is used to measure air pressure in a certain environment. Pressure tendency can forecast short term changes in the weather. Many measurements of air pressure are used within surface weather analysis to help find surface Trough (meteorology), troughs, pressure systems and weather front, frontal boundaries. Barometers and pressure altimeters (the most basic and common type of altimeter) are essentially the same instrument, but used for different purposes. An altimeter is intended to be used at different levels matching the corresponding atmospheric pressure to the altitude, while a barometer is kept at the same level and measures subtle pressure changes caused by weather and elements of weather. The average atmospheric pressure on the Earth's surface varies between 940 and 1040 hPa (mbar). The average atmospheric pressure at sea level is 1013 hPa (mbar). Etymology The word ''wikt:barometer, barometer'' is derived from the Ancient Gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physics
Physics is the scientific study of matter, its Elementary particle, fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular succession of events." It is one of the most fundamental scientific disciplines. "Physics is one of the most fundamental of the sciences. Scientists of all disciplines use the ideas of physics, including chemists who study the structure of molecules, paleontologists who try to reconstruct how dinosaurs walked, and climatologists who study how human activities affect the atmosphere and oceans. Physics is also the foundation of all engineering and technology. No engineer could design a flat-screen TV, an interplanetary spacecraft, or even a better mousetrap without first understanding the basic laws of physics. (...) You will come to see physics as a towering achievement of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
