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86-396: Filtration is a physical separation process that separates solid matter and fluid from a mixture using a filter medium that has a complex structure through which only the fluid can pass. Solid particles that cannot pass through the filter medium are described as oversize and the fluid that passes through is called the filtrate . Oversize particles may form a filter cake on top of

172-446: A centrifugal force several times stronger than gravity replaces gravitational force. A partial vacuum is typically provided to the container below the filter media when laboratory filtration is challenging to speed up the filtering process. Depending on the type of filter being used, the majority of industrial filtration operations employ pressure or vacuum to speed up filtering and reduce the amount of equipment needed. Filter media are

258-622: A falling object is proportional to the square of the time elapsed. This was later confirmed by Italian scientists Jesuits Grimaldi and Riccioli between 1640 and 1650. They also calculated the magnitude of the Earth's gravity by measuring the oscillations of a pendulum. In 1657, Robert Hooke published his Micrographia , in which he hypothesised that the Moon must have its own gravity. In 1666, he added two further principles: that all bodies move in straight lines until deflected by some force and that

344-413: A filter due to a pressure difference—fluid flows from the high-pressure side to the low-pressure side of the filter. The simplest method to achieve this is by gravity which can be seen in the coffeemaker example. In the laboratory, pressure in the form of compressed air on the feed side (or vacuum on the filtrate side) may be applied to make the filtration process faster, though this may lead to clogging or

430-402: A fluid stream but also remove chemical species and biological organisms by entrainment , phagocytosis , adsorption and absorption . Examples include slow sand filters and trickling filters . It is also used as a general term for macrophage in which organisms use a variety of means to filter small food particles from their environment. Examples range from the microscopic Vorticella up to

516-429: A force applied to an object would cause it to deviate from a geodesic. For instance, people standing on the surface of the Earth are prevented from following a geodesic path because the mechanical resistance of the Earth exerts an upward force on them. This explains why moving along the geodesics in spacetime is considered inertial. Einstein's description of gravity was quickly accepted by the majority of physicists, as it

602-466: A force, the ancient Greek philosopher Archimedes discovered the center of gravity of a triangle. He postulated that if two equal weights did not have the same center of gravity, the center of gravity of the two weights together would be in the middle of the line that joins their centers of gravity. Two centuries later, the Roman engineer and architect Vitruvius contended in his De architectura that gravity

688-399: A groundbreaking book called Philosophiæ Naturalis Principia Mathematica ( Mathematical Principles of Natural Philosophy ). In this book, Newton described gravitation as a universal force, and claimed that "the forces which keep the planets in their orbs must [be] reciprocally as the squares of their distances from the centers about which they revolve." This statement was later condensed into

774-412: A mixture instead of a single pure component. A good example of an incomplete separation technique is oil refining. Crude oil occurs naturally as a mixture of various hydrocarbons and impurities. The refining process splits this mixture into other, more valuable mixtures such as natural gas , gasoline and chemical feedstocks , none of which are pure substances, but each of which must be separated from

860-451: A new approach to quantum mechanics) is required. Testing the predictions of general relativity has historically been difficult, because they are almost identical to the predictions of Newtonian gravity for small energies and masses. Still, since its development, an ongoing series of experimental results have provided support for the theory: In 1919, the British astrophysicist Arthur Eddington

946-469: A similar function. Biofilms are often complex communities of bacteria, phages, yeasts and often more complex organisms including protozoa , rotifers and annelids which form dynamic and complex, frequently gelatinous films on wet substrates. Such biofilms coat the rocks of most rivers and the sea and they provide the key filtration capability of the Schmutzdecke on the surface of slow sand filters and

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1032-429: A simple motion, will continue to move in a straight line, unless continually deflected from it by some extraneous force, causing them to describe a circle, an ellipse, or some other curve. 3. That this attraction is so much the greater as the bodies are nearer. As to the proportion in which those forces diminish by an increase of distance, I own I have not discovered it.... Hooke's 1674 Gresham lecture, An Attempt to prove

1118-432: A stem in the filter funnel, there is a decrease in the surface area of contact between the solution and the stem of the filter funnel, hence preventing re-crystallization of solid in the funnel, and adversely affecting the filtration process. Cold filtration method is the use of an ice bath to rapidly cool the solution to be crystallized rather than leaving it to cool slowly in the room atmosphere. This technique results in

1204-488: A sufficiently large and compact object. General relativity states that gravity acts on light and matter equally, meaning that a sufficiently massive object could warp light around it and create a gravitational lens . This phenomenon was first confirmed by observation in 1979 using the 2.1 meter telescope at Kitt Peak National Observatory in Arizona, which saw two mirror images of the same quasar whose light had been bent around

1290-526: A theory of general relativity which was able to accurately model Mercury's orbit. In general relativity, the effects of gravitation are ascribed to spacetime curvature instead of a force. Einstein began to toy with this idea in the form of the equivalence principle , a discovery which he later described as "the happiest thought of my life." In this theory, free fall is considered to be equivalent to inertial motion, meaning that free-falling inertial objects are accelerated relative to non-inertial observers on

1376-405: A theory of gravity consistent with quantum mechanics , a quantum gravity theory, which would allow gravity to be united in a common mathematical framework (a theory of everything ) with the other three fundamental interactions of physics. Gravitation , also known as gravitational attraction, is the mutual attraction between all masses in the universe. Gravity is the gravitational attraction at

1462-412: A tower. In the late 16th century, Galileo Galilei 's careful measurements of balls rolling down inclines allowed him to firmly establish that gravitational acceleration is the same for all objects. Galileo postulated that air resistance is the reason that objects with a low density and high surface area fall more slowly in an atmosphere. In 1604, Galileo correctly hypothesized that the distance of

1548-434: A water current to the mouth whilst the hairs on the legs trap any particle. Others such as some caddis flies spin fine webs in the water flow to trap particles. Many filtration processes include more than one filtration mechanism, and particulates are often removed from the fluid first to prevent clogging of downstream elements. Particulate filtration includes: Adsorption filtration removes contaminants by adsorption of

1634-441: Is a fundamental interaction primarily observed as mutual attraction between all things that have mass . Gravity is, by far, the weakest of the four fundamental interactions, approximately 10 times weaker than the strong interaction , 10 times weaker than the electromagnetic force and 10 times weaker than the weak interaction . As a result, it has no significant influence at the level of subatomic particles . However, gravity

1720-414: Is achieved by some form of interaction between the substance or objects to be removed and the filter. The substance that is to pass through the filter must be a fluid , i.e. a liquid or gas . Methods of filtration vary depending on the location of the targeted material, i.e. whether it is dissolved in the fluid phase or suspended as a solid. There are several laboratory filtration techniques depending on

1806-412: Is carried out by rapidly rotating the substance to be filtered. The more dense material is separated from the less dense matter by the horizontal rotation. Gravity filtration is the process of pouring the mixture from a higher location to a lower one. It is frequently accomplished via simple filtration, which involves placing filter paper in a glass funnel with the liquid passing through by gravity while

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1892-458: Is especially vexing to physicists because the other three fundamental forces (strong force, weak force and electromagnetism) were reconciled with a quantum framework decades ago. As a result, modern researchers have begun to search for a theory that could unite both gravity and quantum mechanics under a more general framework. One path is to describe gravity in the framework of quantum field theory , which has been successful to accurately describe

1978-409: Is most accurately described by the general theory of relativity , proposed by Albert Einstein in 1915, which describes gravity not as a force, but as the curvature of spacetime , caused by the uneven distribution of mass, and causing masses to move along geodesic lines. The most extreme example of this curvature of spacetime is a black hole , from which nothing—not even light—can escape once past

2064-530: Is not dependent on a substance's weight but rather on its "nature". In the 6th century CE, the Byzantine Alexandrian scholar John Philoponus proposed the theory of impetus, which modifies Aristotle's theory that "continuation of motion depends on continued action of a force" by incorporating a causative force that diminishes over time. In 628 CE, the Indian mathematician and astronomer Brahmagupta proposed

2150-451: Is often expressed in the form G μ ν + Λ g μ ν = κ T μ ν , {\displaystyle G_{\mu \nu }+\Lambda g_{\mu \nu }=\kappa T_{\mu \nu },} where G μν is the Einstein tensor , g μν is the metric tensor , T μν is the stress–energy tensor , Λ

2236-535: Is the cosmological constant , G {\displaystyle G} is the Newtonian constant of gravitation and c {\displaystyle c} is the speed of light . The constant κ = 8 π G c 4 {\displaystyle \kappa ={\frac {8\pi G}{c^{4}}}} is referred to as the Einstein gravitational constant. A major area of research

2322-445: Is the discovery of exact solutions to the Einstein field equations. Solving these equations amounts to calculating a precise value for the metric tensor (which defines the curvature and geometry of spacetime) under certain physical conditions. There is no formal definition for what constitutes such solutions, but most scientists agree that they should be expressable using elementary functions or linear differential equations . Some of

2408-516: Is the most significant interaction between objects at the macroscopic scale , and it determines the motion of planets , stars , galaxies , and even light . On Earth , gravity gives weight to physical objects , and the Moon's gravity is responsible for sublunar tides in the oceans. The corresponding antipodal tide is caused by the inertia of the Earth and Moon orbiting one another. Gravity also has many important biological functions, helping to guide

2494-472: The International System of Units (SI). The force of gravity on Earth is the resultant (vector sum) of two forces: (a) The gravitational attraction in accordance with Newton's universal law of gravitation, and (b) the centrifugal force, which results from the choice of an earthbound, rotating frame of reference. The force of gravity is weakest at the equator because of the centrifugal force caused by

2580-408: The basking shark , one of the largest fishes, and the baleen whales , all of which are described as filter feeders . Filters may be used for the purpose of removing unwanted liquid from a solid residue, cleaning unwanted solids from a liquid, or simply to separate the solid from the liquid. There are many different methods of filtration; all aim to attain the separation of substances. Separation

2666-422: The kidneys function by renal filtration whereby the glomerulus selectively removes undesirable constituents such as urea , followed by selective reabsorption of many substances essential for the body to maintain homeostasis. The complete process is termed excretion by urination . Similar but often less complex solutions are deployed in all animals, even the protozoa , where the contractile vacuole provides

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2752-478: The Annual Motion of the Earth , explained that gravitation applied to "all celestial bodies" In 1684, Newton sent a manuscript to Edmond Halley titled De motu corporum in gyrum ('On the motion of bodies in an orbit') , which provided a physical justification for Kepler's laws of planetary motion . Halley was impressed by the manuscript and urged Newton to expand on it, and a few years later Newton published

2838-629: The Big Bang. Neutron star and black hole formation also create detectable amounts of gravitational radiation. This research was awarded the Nobel Prize in Physics in 2017. In December 2012, a research team in China announced that it had produced measurements of the phase lag of Earth tides during full and new moons which seem to prove that the speed of gravity is equal to the speed of light. This means that if

2924-452: The Earth's rotation and because points on the equator are furthest from the center of the Earth. The force of gravity varies with latitude and increases from about 9.780 m/s at the Equator to about 9.832 m/s at the poles. General relativity predicts that energy can be transported out of a system through gravitational radiation. The first indirect evidence for gravitational radiation

3010-459: The Earth) is surrounded by its own gravitational field, which can be conceptualized with Newtonian physics as exerting an attractive force on all objects. Assuming a spherically symmetrical planet, the strength of this field at any given point above the surface is proportional to the planetary body's mass and inversely proportional to the square of the distance from the center of the body. The strength of

3096-602: The Sun suddenly disappeared, the Earth would keep orbiting the vacant point normally for 8 minutes, which is the time light takes to travel that distance. The team's findings were released in Science Bulletin in February 2013. In October 2017, the LIGO and Virgo detectors received gravitational wave signals within 2 seconds of gamma ray satellites and optical telescopes seeing signals from

3182-459: The attachment of desirable biomass and critical nutrients to immobilized support. So that water may be reused for various processes, advances in biofiltration methods assist in removing significant volumes of effluents from wastewater . Systems for biologically treating wastewater are crucial for enhancing both human health and water quality . Biofilm technology, the formation of biofilms on various filter media, and other factors have an impact on

3268-496: The attractive force is stronger for closer bodies. In a communication to the Royal Society in 1666, Hooke wrote I will explain a system of the world very different from any yet received. It is founded on the following positions. 1. That all the heavenly bodies have not only a gravitation of their parts to their own proper centre, but that they also mutually attract each other within their spheres of action. 2. That all bodies having

3354-422: The black hole's event horizon . However, for most applications, gravity is well approximated by Newton's law of universal gravitation , which describes gravity as a force causing any two bodies to be attracted toward each other, with magnitude proportional to the product of their masses and inversely proportional to the square of the distance between them. Current models of particle physics imply that

3440-562: The bottom, where it often forms a firm cake . The liquid above can then be decanted. This method is especially useful for separating solids that do not filter well, such as gelatinous or fine particles. These solids can clog or pass through the filter, respectively. Biological filtration may take place inside an organism, or the biological component may be grown on a medium in the material being filtered. Removal of solids, emulsified components, organic chemicals and ions may be achieved by ingestion and digestion, adsorption or absorption. Because of

3526-428: The cheaper and safer perlite . Activated carbon is often used in industrial applications that require changes in the filtrate's properties, such as altering colour or odour. These filter aids can be used in two different ways. They can be used as a precoat before the slurry is filtered. This will prevent gelatinous-type solids from plugging the filter medium and also give a clearer filtrate. They can also be added to

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3612-569: The complexity of biological interactions, especially in multi-organism communities, it is often not possible to determine which processes are achieving the filtration result. At the molecular level, it may often be by individual catalytic enzyme actions within an individual organism. The waste products of some organisms may subsequently broken down by other organisms to extract as much energy as possible and in so doing reduce complex organic molecules to very simple inorganic species such as water, carbon dioxide and nitrogen. In mammals, reptiles, and birds,

3698-449: The contaminant by the filter medium. This requires intimate contact between the filter medium and the filtrate, and takes time for diffusion to bring the contaminant into direct contact with the medium while passing through it, referred to as dwell time . Slower flow also reduces pressure drop across the filter. Applications include: Combined applications include: Separation process Processes are often classified according to

3784-413: The contaminated granules than to clean the solid sieve. Filter media can be cleaned by rinsing with solvents or detergents or backwashing. Alternatively, in engineering applications, such as swimming pool water treatment plants, they may be cleaned by backwashing . Self-cleaning screen filters utilize point-of-suction backwashing to clean the screen without interrupting system flow. Fluids flow through

3870-410: The desired outcome namely, hot, cold and vacuum filtration . Some of the major purposes of obtaining the desired outcome are, for the removal of impurities from a mixture or, for the isolation of solids from a mixture. Hot filtration method is mainly used to separate solids from a hot solution. This is done to prevent crystal formation in the filter funnel and other apparatus that come in contact with

3956-494: The earliest instance of gravity in the universe, possibly in the form of quantum gravity , supergravity or a gravitational singularity , along with ordinary space and time , developed during the Planck epoch (up to 10 seconds after the birth of the universe), possibly from a primeval state, such as a false vacuum , quantum vacuum or virtual particle , in a currently unknown manner. Scientists are currently working to develop

4042-466: The fall of bodies. The mid-16th century Italian physicist Giambattista Benedetti published papers claiming that, due to specific gravity , objects made of the same material but with different masses would fall at the same speed. With the 1586 Delft tower experiment , the Flemish physicist Simon Stevin observed that two cannonballs of differing sizes and weights fell at the same rate when dropped from

4128-403: The film on the filter media of trickling filters which are used to create potable water and treat sewage respectively. An example of a biofilm is a biological slime, which may be found in lakes, rivers, rocks, etc. The utilization of single- or dual-species biofilms is a novel technology since natural biofilms are sluggishly developing. The use of biofilms in the biofiltration process allows for

4214-400: The filter and may also block the filter lattice, preventing the fluid phase from crossing the filter, known as blinding . The size of the largest particles that can successfully pass through a filter is called the effective pore size of that filter. The separation of solid and fluid is imperfect; solids will be contaminated with some fluid and filtrate will contain fine particles (depending on

4300-409: The filter media. Gravity , centrifugation, applying pressure to the fluid above the filter, applying a vacuum below the filter, or a combination of these factors may all contribute to this force. In both straightforward laboratory filtrations and massive sand-bed filters, gravitational force alone may be utilized. Centrifuges with a bowl holding a porous filter media can be thought of as filters in which

4386-426: The filter. Filtration is a more efficient method for the separation of mixtures than decantation but is much more time-consuming. If very small amounts of solution are involved, most of the solution may be soaked up by the filter medium. An alternative to filtration is centrifugation . Instead of filtering the mixture of solid and liquid particles, the mixture is centrifuged to force the (usually) denser solid to

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4472-433: The following inverse-square law: F = G m 1 m 2 r 2 , {\displaystyle F=G{\frac {m_{1}m_{2}}{r^{2}}},} where F is the force, m 1 and m 2 are the masses of the objects interacting, r is the distance between the centers of the masses and G is the gravitational constant 6.674 × 10  m ⋅kg ⋅s . Newton's Principia

4558-418: The formation of very small crystals as opposed to getting large crystals by cooling the solution at room temperature. Vacuum filtration technique is mostly preferred for small batches of solution to dry small crystals quickly. This method requires a Büchner funnel , filter paper of a smaller diameter than the funnel, Büchner flask , and rubber tubing to connect to a vacuum source. Centrifugal filtration

4644-409: The framework for the understanding of gravity. Physicists continue to work to find solutions to the Einstein field equations that form the basis of general relativity and continue to test the theory, finding excellent agreement in all cases. The Einstein field equations are a system of 10 partial differential equations which describe how matter affects the curvature of spacetime. The system

4730-458: The galaxy YGKOW G1 . Frame dragging , the idea that a rotating massive object should twist spacetime around it, was confirmed by Gravity Probe B results in 2011. In 2015, the LIGO observatory detected faint gravitational waves , the existence of which had been predicted by general relativity. Scientists believe that the waves emanated from a black hole merger that occurred 1.5 billion light-years away. Every planetary body (including

4816-514: The gravitational field is numerically equal to the acceleration of objects under its influence. The rate of acceleration of falling objects near the Earth's surface varies very slightly depending on latitude, surface features such as mountains and ridges, and perhaps unusually high or low sub-surface densities. For purposes of weights and measures, a standard gravity value is defined by the International Bureau of Weights and Measures , under

4902-468: The ground. In contrast to Newtonian physics , Einstein believed that it was possible for this acceleration to occur without any force being applied to the object. Einstein proposed that spacetime is curved by matter, and that free-falling objects are moving along locally straight paths in curved spacetime. These straight paths are called geodesics . As in Newton's first law of motion, Einstein believed that

4988-487: The growth of plants through the process of gravitropism and influencing the circulation of fluids in multicellular organisms . The gravitational attraction between the original gaseous matter in the universe caused it to coalesce and form stars which eventually condensed into galaxies, so gravity is responsible for many of the large-scale structures in the universe. Gravity has an infinite range, although its effects become weaker as objects get farther away. Gravity

5074-448: The growth structure and function of these biofilms. To conduct a thorough investigation of the composition, diversity, and dynamics of biofilms, it also takes on a variety of traditional and contemporary molecular approaches. Filter feeders are organisms that obtain their food by filtering their, generally aquatic, environment. Many of the protozoa are filter feeders using a range of adaptations including rigid spikes of protoplasm held in

5160-440: The idea that gravity is an attractive force that draws objects to the Earth and used the term gurutvākarṣaṇ to describe it. In the ancient Middle East , gravity was a topic of fierce debate. The Persian intellectual Al-Biruni believed that the force of gravity was not unique to the Earth, and he correctly assumed that other heavenly bodies should exert a gravitational attraction as well. In contrast, Al-Khazini held

5246-596: The idea that time runs more slowly in the presence of a gravitational field. The time delay of light passing close to a massive object was first identified by Irwin I. Shapiro in 1964 in interplanetary spacecraft signals. In 1971, scientists discovered the first-ever black hole in the galaxy Cygnus . The black hole was detected because it was emitting bursts of x-rays as it consumed a smaller star, and it came to be known as Cygnus X-1 . This discovery confirmed yet another prediction of general relativity, because Einstein's equations implied that light could not escape from

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5332-417: The insoluble solid particles are caught by the filter paper. Filter cones, fluted filters, or filtering pipets can all be employed, depending on the amount of the substance at hand. Gravity filtration is in widespread everyday use, for example for straining cooking water from food, or removing contaminants from a liquid. Only when a driving force is supplied will the fluid to be filtered be able to flow through

5418-457: The interactions of three or more massive bodies (the " n -body problem"), and some scientists suspect that the Einstein field equations will never be solved in this context. However, it is still possible to construct an approximate solution to the field equations in the n -body problem by using the technique of post-Newtonian expansion . In general, the extreme nonlinearity of the Einstein field equations makes it difficult to solve them in all but

5504-463: The mass in the Universe towards it. He also thought that the speed of a falling object should increase with its weight, a conclusion that was later shown to be false. While Aristotle's view was widely accepted throughout Ancient Greece, there were other thinkers such as Plutarch who correctly predicted that the attraction of gravity was not unique to the Earth. Although he did not understand gravity as

5590-434: The materials used to do the separation of materials. Two main types of filter media are employed in laboratories: Surface filters allow the solid particles, i.e. the residue, to be collected intact; depth filters do not. However, the depth filter is less prone to clogging due to the greater surface area where the particles can be trapped. Also, when the solid particles are very fine, it is often cheaper and easier to discard

5676-473: The modern industrial economy. The purpose of separation may be: Separations may be performed on a small scale, as in a laboratory for analytical purposes, or on a large scale, as in a chemical plant . Some types of separation require complete purification of a certain component. An example is the production of aluminum metal from bauxite ore through electrolysis refining . In contrast, an incomplete separation process may specify an output to consist of

5762-429: The most notable solutions of the equations include: Today, there remain many important situations in which the Einstein field equations have not been solved. Chief among these is the two-body problem , which concerns the geometry of spacetime around two mutually interacting massive objects, such as the Sun and the Earth, or the two stars in a binary star system . The situation gets even more complicated when considering

5848-405: The most specific cases. Despite its success in predicting the effects of gravity at large scales, general relativity is ultimately incompatible with quantum mechanics . This is because general relativity describes gravity as a smooth, continuous distortion of spacetime, while quantum mechanics holds that all forces arise from the exchange of discrete particles known as quanta . This contradiction

5934-422: The orbit of the planet Mercury which could not be explained by Newton's theory: the perihelion of the orbit was increasing by about 42.98 arcseconds per century. The most obvious explanation for this discrepancy was an as-yet-undiscovered celestial body, such as a planet orbiting the Sun even closer than Mercury, but all efforts to find such a body turned out to be fruitless. In 1915, Albert Einstein developed

6020-462: The other fundamental interactions . The electromagnetic force arises from an exchange of virtual photons , where the QFT description of gravity is that there is an exchange of virtual gravitons . This description reproduces general relativity in the classical limit . However, this approach fails at short distances of the order of the Planck length , where a more complete theory of quantum gravity (or

6106-435: The particular properties they exploit to achieve separation. If no single difference can be used to accomplish the desired separation, multiple operations can often be combined to achieve the desired end. With a few exceptions, elements or compounds exist in nature in an impure state. Often these raw materials must go through a separation before they can be put to productive use, making separation techniques essential for

6192-486: The passage of fine particles. Alternatively, the liquid may flow through the filter by the force exerted by a pump , a method commonly used in industry when a reduced filtration time is important. In this case, the filter need not be mounted vertically. Certain filter aids may be used to aid filtration. These are often incompressible diatomaceous earth , or kieselguhr, which is composed primarily of silica . Also used are wood cellulose and other inert porous solids such as

6278-496: The planet's actual trajectory. In order to explain this discrepancy, many astronomers speculated that there might be a large object beyond the orbit of Uranus which was disrupting its orbit. In 1846, the astronomers John Couch Adams and Urbain Le Verrier independently used Newton's law to predict Neptune's location in the night sky, and the planet was discovered there within a day. Eventually, astronomers noticed an eccentricity in

6364-418: The pore size, filter thickness and biological activity). Filtration occurs both in nature and in engineered systems; there are biological , geological , and industrial forms. In everyday usage the verb "strain" is more often used; for example, using a colander to drain cooking water from cooked pasta . Filtration is also used to describe biological and physical systems that not only separate solids from

6450-422: The raw crude. In both complete separation and incomplete separation, a series or cascade of separations may be necessary to obtain the desired end products. In the case of oil refining, crude is subjected to a long series of individual distillation steps, each of which produces a different product or intermediate . Gravity In physics, gravity (from Latin gravitas  'weight' )

6536-786: The same position as Aristotle that all matter in the Universe is attracted to the center of the Earth. In the mid-16th century, various European scientists experimentally disproved the Aristotelian notion that heavier objects fall at a faster rate. In particular, the Spanish Dominican priest Domingo de Soto wrote in 1551 that bodies in free fall uniformly accelerate. De Soto may have been influenced by earlier experiments conducted by other Dominican priests in Italy, including those by Benedetto Varchi , Francesco Beato, Luca Ghini , and Giovan Bellaso which contradicted Aristotle's teachings on

6622-423: The scientific community. In 1959, American physicists Robert Pound and Glen Rebka performed an experiment in which they used gamma rays to confirm the prediction of gravitational time dilation . By sending the rays down a 74-foot tower and measuring their frequency at the bottom, the scientists confirmed that light is redshifted as it moves towards a source of gravity. The observed redshift also supported

6708-406: The slurry before filtration. This increases the porosity of the cake and reduces the resistance of the cake during filtration. In a rotary filter, the filter aid may be applied as a precoat; subsequently, thin slices of this layer are sliced off with the cake. The use of filter aids is usually limited to cases where the cake is discarded or where the precipitate can be chemically separated from

6794-413: The solution. As a result, the apparatus and the solution used are heated to prevent the rapid decrease in temperature which in turn, would lead to the crystallisation of the solids in the funnel and hinder the filtration process. One of the most important measures to prevent the formation of crystals in the funnel and to undergo effective hot filtration is the use stemless filter funnel. Due to the absence of

6880-431: The surface of a planet or other celestial body; gravity may also include, in addition to gravitation, the centrifugal force resulting from the planet's rotation (see § Earth's gravity ) . The nature and mechanism of gravity were explored by a wide range of ancient scholars. In Greece , Aristotle believed that objects fell towards the Earth because the Earth was the center of the Universe and attracted all of

6966-544: The water flow as in the suctoria to various arrangements of beating cillia to direct particles to the mouth including organisms such as Vorticella which have a complex ring of cilia which create a vortex in the flow drafting particles into the oral cavity. Similar feeding techniques are used by the Rotifera and the Ectoprocta . Many aquatic arthropods are filter feeders. Some use rhythmical beating of abdominal limbs to create

7052-421: Was able to confirm the predicted gravitational lensing of light during that year's solar eclipse . Eddington measured starlight deflections twice those predicted by Newtonian corpuscular theory, in accordance with the predictions of general relativity. Although Eddington's analysis was later disputed, this experiment made Einstein famous almost overnight and caused general relativity to become widely accepted in

7138-468: Was able to explain a wide variety of previously baffling experimental results. In the coming years, a wide range of experiments provided additional support for the idea of general relativity. Today, Einstein's theory of relativity is used for all gravitational calculations where absolute precision is desired, although Newton's inverse-square law is accurate enough for virtually all ordinary calculations. In modern physics , general relativity remains

7224-410: Was measured on 14 September 2015 by the LIGO detectors. The gravitational waves emitted during the collision of two black holes 1.3 billion light years from Earth were measured. This observation confirms the theoretical predictions of Einstein and others that such waves exist. It also opens the way for practical observation and understanding of the nature of gravity and events in the Universe including

7310-537: Was through measurements of the Hulse–Taylor binary in 1973. This system consists of a pulsar and neutron star in orbit around one another. Its orbital period has decreased since its initial discovery due to a loss of energy, which is consistent for the amount of energy loss due to gravitational radiation. This research was awarded the Nobel Prize in Physics in 1993. The first direct evidence for gravitational radiation

7396-531: Was well received by the scientific community, and his law of gravitation quickly spread across the European world. More than a century later, in 1821, his theory of gravitation rose to even greater prominence when it was used to predict the existence of Neptune . In that year, the French astronomer Alexis Bouvard used this theory to create a table modeling the orbit of Uranus , which was shown to differ significantly from

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