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112-748: Together with other units of weight of the Imperial Russian weight measurement system , the USSR officially abolished the pood in 1924. The term remained in widespread use until at least the 1940s. In his 1953 short story " Matryona's Place ", Aleksandr Solzhenitsyn presents the pood as still in use amongst the Khrushchev-era Soviet peasants. Its usage is preserved in modern Russian in certain specific cases, e.g., in reference to sports weights, such as traditional Russian kettlebells , cast in multiples and fractions of 16 kg (which

224-574: A gymnasium and a colonnade ( peripatos ), from which the school acquired the name Peripatetic . Aristotle conducted courses and research at the school for the next twelve years. He often lectured small groups of distinguished students and, along with some of them, such as Theophrastus , Eudemus , and Aristoxenus , Aristotle built a large library which included manuscripts, maps, and museum objects. While in Athens, his wife Pythias died and Aristotle became involved with Herpyllis of Stagira. They had

336-476: A lever mechanism – a lever-balance. The standard masses are often referred to, non-technically, as "weights". Since any variations in gravity will act equally on the unknown and the known weights, a lever-balance will indicate the same value at any location on Earth. Therefore, balance "weights" are usually calibrated and marked in mass units, so the lever-balance measures mass by comparing the Earth's attraction on

448-458: A weighing scale ) is an entirely acceptable way of measuring mass. Similarly, a balance measures mass indirectly by comparing the weight of the measured item to that of an object(s) of known mass. Since the measured item and the comparison mass are in virtually the same location, so experiencing the same gravitational field , the effect of varying gravity does not affect the comparison or the resulting measurement. The Earth's gravitational field

560-541: A "survival of the fittest" origin of living things and their organs, and ridiculed the idea that accidents could lead to orderly results. To put his views into modern terms, he nowhere says that different species can have a common ancestor , or that one kind can change into another , or that kinds can become extinct . Aristotle did not do experiments in the modern sense. He used the ancient Greek term pepeiramenoi to mean observations, or at most investigative procedures like dissection. In Generation of Animals , he finds

672-419: A body by gravity. This is often expressed in the formula W = mg , where W is the weight, m the mass of the object, and g gravitational acceleration . In 1901, the 3rd General Conference on Weights and Measures (CGPM) established this as their official definition of weight : The word weight denotes a quantity of the same nature as a force : the weight of a body is the product of its mass and

784-562: A daughter whom they also named Pythias. In 343/42 BC, Aristotle was invited to Pella by Philip II of Macedon in order to become the tutor to his thirteen-year-old son Alexander ; a choice perhaps influenced by the relationship of Aristotle's family with the Macedonian dynasty. Aristotle taught Alexander at the private school of Mieza , in the gardens of the Nymphs , the royal estate near Pella. Alexander's education probably included

896-438: A fertilized hen's egg of a suitable stage and opens it to see the embryo's heart beating inside. Instead, he practiced a different style of science: systematically gathering data, discovering patterns common to whole groups of animals, and inferring possible causal explanations from these. This style is common in modern biology when large amounts of data become available in a new field, such as genomics . It does not result in

1008-497: A fluid such as air. In this system, heavy bodies in steady fall indeed travel faster than light ones (whether friction is ignored, or not ), and they do fall more slowly in a denser medium. Newton's "forced" motion corresponds to Aristotle's "violent" motion with its external agent, but Aristotle's assumption that the agent's effect stops immediately it stops acting (e.g., the ball leaves the thrower's hand) has awkward consequences: he has to suppose that surrounding fluid helps to push

1120-455: A house is the bricks, stones, timbers, etc., or whatever constitutes the potential house, while the form of the substance is the actual house, namely 'covering for bodies and chattels' or any other differentia that let us define something as a house. The formula that gives the components is the account of the matter, and the formula that gives the differentia is the account of the form. Like his teacher Plato, Aristotle's philosophy aims at

1232-597: A linear scale, and noted various exceptions, such as that sharks had a placenta like the tetrapods. To a modern biologist, the explanation, not available to Aristotle, is convergent evolution . Philosophers of science have generally concluded that Aristotle was not interested in taxonomy, but zoologists who studied this question in the early 21st century think otherwise. He believed that purposive final causes guided all natural processes; this teleological view justified his observed data as an expression of formal design. Aristotle's psychology , given in his treatise On

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1344-508: A man of mass 180 pounds weighs only about 30 pounds-force when visiting the Moon. In most modern scientific work, physical quantities are measured in SI units. The SI unit of weight is the same as that of force: the newton (N) – a derived unit which can also be expressed in SI base units as kg⋅m/s (kilograms times metres per second squared). In commercial and everyday use, the term "weight"

1456-480: A number of subjects, such as ethics and politics , as well as standard literary texts, like Euripides and Homer . It is likely that during Aristotle's time in the Macedonian court, other prominent nobles, like Ptolemy and Cassander , would have occasionally attended his lectures. Aristotle encouraged Alexander toward eastern conquest, and his own attitude towards Persia was strongly ethnocentric . In one famous example, he counsels Alexander to be "a leader to

1568-435: A part of particular things. For example, it is possible that there is no particular good in existence, but "good" is still a proper universal form. Aristotle disagreed with Plato on this point, arguing that all universals are instantiated at some period of time, and that there are no universals that are unattached to existing things. In addition, Aristotle disagreed with Plato about the location of universals. Where Plato spoke of

1680-498: A priori principles. Aristotle's "natural philosophy" spans a wide range of natural phenomena including those now covered by physics, biology and other natural sciences. In Aristotle's terminology, "natural philosophy" is a branch of philosophy examining the phenomena of the natural world, and includes fields that would be regarded today as physics, biology and other natural sciences. Aristotle's work encompassed virtually all facets of intellectual inquiry. Aristotle makes philosophy in

1792-418: A property or a relation to other things. When one looks at an apple, for example, one sees an apple, and one can also analyse a form of an apple. In this distinction, there is a particular apple and a universal form of an apple. Moreover, one can place an apple next to a book, so that one can speak of both the book and apple as being next to each other. Plato argued that there are some universal forms that are not

1904-408: A quality opposed to buoyancy , with the conflict between the two determining if an object sinks or floats. The first operational definition of weight was given by Euclid , who defined weight as: "the heaviness or lightness of one thing, compared to another, as measured by a balance." Operational balances (rather than definitions) had, however, been around much longer. According to Aristotle, weight

2016-405: A scale in a gravitational field. Gravitational force and weight thereby became essentially frame-dependent quantities. This prompted the abandonment of the concept as superfluous in the fundamental sciences such as physics and chemistry. Nonetheless, the concept remained important in the teaching of physics. The ambiguities introduced by relativity led, starting in the 1960s, to considerable debate in

2128-621: A set of six books called the Organon around 40 BC by Andronicus of Rhodes or others among his followers. The books are: The order of the books (or the teachings from which they are composed) is not certain, but this list was derived from analysis of Aristotle's writings. It goes from the basics, the analysis of simple terms in the Categories, the analysis of propositions and their elementary relations in On Interpretation , to

2240-549: A son whom Aristotle named after his father, Nicomachus . This period in Athens, between 335 and 323 BC, is when Aristotle is believed to have composed many of his philosophical works. He wrote many dialogues, of which only fragments have survived. Those works that have survived are in treatise form and were not, for the most part, intended for widespread publication; they are generally thought to be lecture aids for his students. His most important treatises include Physics , Metaphysics , Nicomachean Ethics , Politics , On

2352-457: A third of his original output has survived , none of it intended for publication. Aristotle provided a complex synthesis of the various philosophies existing prior to him. His teachings and methods of inquiry have had a significant impact across the world, and remain a subject of contemporary philosophical discussion. Aristotle's views profoundly shaped medieval scholarship . The influence of his physical science extended from late antiquity and

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2464-562: A thrown stone, in the Physics (254b10), and "natural motion", such as of a falling object, in On the Heavens (300a20). In violent motion, as soon as the agent stops causing it, the motion stops also: in other words, the natural state of an object is to be at rest, since Aristotle does not address friction . With this understanding, it can be observed that, as Aristotle stated, heavy objects (on

2576-544: A woman with origins from Chalcis , Euboea . Nicomachus was said to have belonged to the medical guild of Asclepiadae and was likely responsible for Aristotle's early interest in biology and medicine. Ancient tradition held that Aristotle's family descended from the legendary physician Asclepius and his son Machaon . Both of Aristotle's parents died when he was still at a young age and Proxenus of Atarneus became his guardian. Although little information about Aristotle's childhood has survived, he probably spent some time in

2688-466: Is pood rounded to metric units). For example, a 24 kg kettlebell is commonly referred to as "one-and-half pood kettlebell" ( polutorapudovaya girya ). It is also sometimes used when reporting the amounts of bulk agricultural production, such as grains or potatoes. An old Russian proverb reads, "You know a man when you have eaten a pood of salt with him." ( Russian : Человека узнаешь, когда с ним пуд соли съешь. ) In modern colloquial Russian,

2800-425: Is a change where the substrate of the thing that has undergone the change has itself changed. In that particular change he introduces the concept of potentiality ( dynamis ) and actuality ( entelecheia ) in association with the matter and the form. Referring to potentiality, this is what a thing is capable of doing or being acted upon if the conditions are right and it is not prevented by something else. For example,

2912-454: Is a historical accident: his works on botany have been lost, but two books on plants by his pupil Theophrastus have survived. Aristotle reports on the sea-life visible from observation on Lesbos and the catches of fishermen. He describes the catfish , electric ray , and frogfish in detail, as well as cephalopods such as the octopus and paper nautilus . His description of the hectocotyl arm of cephalopods, used in sexual reproduction,

3024-419: Is also a final cause or end. Then Aristotle proceeds and concludes that the actuality is prior to potentiality in formula, in time and in substantiality. With this definition of the particular substance (i.e., matter and form), Aristotle tries to solve the problem of the unity of the beings, for example, "what is it that makes a man one"? Since, according to Plato there are two Ideas: animal and biped, how then

3136-455: Is an intrinsic property of matter , whereas weight is a force that results from the action of gravity on matter: it measures how strongly the force of gravity pulls on that matter. However, in most practical everyday situations the word "weight" is used when, strictly, "mass" is meant. For example, most people would say that an object "weighs one kilogram", even though the kilogram is a unit of mass. The distinction between mass and weight

3248-490: Is immersed in a fluid the displacement of the fluid will cause an upward force on the object, making it appear lighter when weighed on a scale. The apparent weight may be similarly affected by levitation and mechanical suspension. When the gravitational definition of weight is used, the operational weight measured by an accelerating scale is often also referred to as the apparent weight. In modern scientific usage, weight and mass are fundamentally different quantities: mass

3360-541: Is man a unity? However, according to Aristotle, the potential being (matter) and the actual one (form) are one and the same. Aristotle's immanent realism means his epistemology is based on the study of things that exist or happen in the world, and rises to knowledge of the universal, whereas for Plato epistemology begins with knowledge of universal Forms (or ideas) and descends to knowledge of particular imitations of these. Aristotle uses induction from examples alongside deduction , whereas Plato relies on deduction from

3472-474: Is not uniform but can vary by as much as 0.5% at different locations on Earth (see Earth's gravity ). These variations alter the relationship between weight and mass, and must be taken into account in high-precision weight measurements that are intended to indirectly measure mass. Spring scales , which measure local weight, must be calibrated at the location at which the objects will be used to show this standard weight, to be legal for commerce. This table shows

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3584-623: Is that of force , which in the International System of Units (SI) is the newton . For example, an object with a mass of one kilogram has a weight of about 9.8 newtons on the surface of the Earth, and about one-sixth as much on the Moon . Although weight and mass are scientifically distinct quantities, the terms are often confused with each other in everyday use (e.g. comparing and converting force weight in pounds to mass in kilograms and vice versa). Further complications in elucidating

3696-411: Is the cgs unit of force and is not a part of SI, while weights measured in the cgs unit of mass, the gram, remain a part of SI. The sensation of weight is caused by the force exerted by fluids in the vestibular system , a three-dimensional set of tubes in the inner ear . It is actually the sensation of g-force , regardless of whether this is due to being stationary in the presence of gravity, or, if

3808-413: Is the fulfilment of the end of the potentiality. Because the end ( telos ) is the principle of every change, and potentiality exists for the sake of the end, actuality, accordingly, is the end. Referring then to the previous example, it can be said that an actuality is when a plant does one of the activities that plants do. For that for the sake of which ( to hou heneka ) a thing is, is its principle, and

3920-487: Is the surface of the Earth, the weight according to the ISO and gravitational definitions differ only by the centrifugal effects due to the rotation of the Earth. In many real world situations the act of weighing may produce a result that differs from the ideal value provided by the definition used. This is usually referred to as the apparent weight of the object. A common example of this is the effect of buoyancy , when an object

4032-518: Is unimportant for many practical purposes because the strength of gravity does not vary too much on the surface of the Earth. In a uniform gravitational field, the gravitational force exerted on an object (its weight) is directly proportional to its mass. For example, object A weighs 10 times as much as object B, so therefore the mass of object A is 10 times greater than that of object B. This means that an object's mass can be measured indirectly by its weight, and so, for everyday purposes, weighing (using

4144-402: Is usually used to mean mass, and the verb "to weigh" means "to determine the mass of" or "to have a mass of". Used in this sense, the proper SI unit is the kilogram (kg). In United States customary units , the pound can be either a unit of force or a unit of mass. Related units used in some distinct, separate subsystems of units include the poundal and the slug . The poundal is defined as

4256-976: The Early Middle Ages into the Renaissance , and was not replaced systematically until the Enlightenment and theories such as classical mechanics were developed. He influenced Judeo-Islamic philosophies during the Middle Ages, as well as Christian theology , especially the Neoplatonism of the Early Church and the scholastic tradition of the Catholic Church . Aristotle was revered among medieval Muslim scholars as "The First Teacher", and among medieval Christians like Thomas Aquinas as simply "The Philosopher", while

4368-652: The Early Modern period. John Philoponus (in Late antiquity ) and Galileo (in Early modern period ) are said to have shown by experiment that Aristotle's claim that a heavier object falls faster than a lighter object is incorrect. A contrary opinion is given by Carlo Rovelli , who argues that Aristotle's physics of motion is correct within its domain of validity, that of objects in the Earth 's gravitational field immersed in

4480-525: The Great Comet of 371 BC . Aristotle was one of the first people to record any geological observations. He stated that geological change was too slow to be observed in one person's lifetime. The geologist Charles Lyell noted that Aristotle described such change, including "lakes that had dried up" and "deserts that had become watered by rivers", giving as examples the growth of the Nile delta since

4592-476: The History of Animals in a graded scale of perfection, a nonreligious version of the scala naturae , with man at the top. His system had eleven grades of animal, from highest potential to lowest, expressed in their form at birth: the highest gave live birth to hot and wet creatures, the lowest laid cold, dry mineral-like eggs. Animals came above plants , and these in turn were above minerals. He grouped what

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4704-553: The Macedonian capital, making his first connections with the Macedonian monarchy . At the age of seventeen or eighteen, Aristotle moved to Athens to continue his education at Plato's Academy . He became distinguished as a researcher and lecturer, earning for himself the nickname "mind of the school" by his tutor Plato . In Athens, he probably experienced the Eleusinian Mysteries as he wrote when describing

4816-456: The Milky Way was made up of "those stars which are shaded by the earth from the sun's rays," pointing out partly correctly that if "the size of the sun is greater than that of the earth and the distance of the stars from the earth many times greater than that of the sun, then... the sun shines on all the stars and the earth screens none of them." He also wrote descriptions of comets, including

4928-508: The Physics (215a25), Aristotle effectively states a quantitative law, that the speed, v, of a falling body is proportional (say, with constant c) to its weight, W, and inversely proportional to the density, ρ, of the fluid in which it is falling:; Aristotle implies that in a vacuum the speed of fall would become infinite, and concludes from this apparent absurdity that a vacuum is not possible. Opinions have varied on whether Aristotle intended to state quantitative laws. Henri Carteron held

5040-418: The standard weight . The force whose magnitude is equal to mg newtons is also known as the m kilogram weight (which term is abbreviated to kg-wt ) In the operational definition, the weight of an object is the force measured by the operation of weighing it, which is the force it exerts on its support . Since W is the downward force on the body by the centre of earth and there is no acceleration in

5152-409: The true weight defined by gravity. Although Newtonian physics made a clear distinction between weight and mass, the term weight continued to be commonly used when people meant mass. This led the 3rd General Conference on Weights and Measures (CGPM) of 1901 to officially declare "The word weight denotes a quantity of the same nature as a force : the weight of a body is the product of its mass and

5264-412: The universal . Aristotle's ontology places the universal ( katholou ) in particulars ( kath' hekaston ), things in the world, whereas for Plato the universal is a separately existing form which actual things imitate. For Aristotle, "form" is still what phenomena are based on, but is "instantiated" in a particular substance. Plato argued that all things have a universal form , which could be either

5376-519: The "extreme view" that Aristotle's concept of force was basically qualitative, but other authors reject this. Archimedes corrected Aristotle's theory that bodies move towards their natural resting places; metal boats can float if they displace enough water ; floating depends in Archimedes' scheme on the mass and volume of the object, not, as Aristotle thought, its elementary composition. Aristotle's writings on motion remained influential until

5488-527: The Colonies , were composed by the philosopher for the young prince. After Philip II's assassination in 336 BC, Aristotle returned to Athens for the second and final time a year later. As a metic , Aristotle could not own property in Athens and thus rented a building known as the Lyceum (named after the sacred grove of Apollo Lykeios ), in which he established his own school. The building included

5600-476: The Earth towards the Sun. Newton considered time and space to be absolute. This allowed him to consider concepts as true position and true velocity. Newton also recognized that weight as measured by the action of weighing was affected by environmental factors such as buoyancy. He considered this a false weight induced by imperfect measurement conditions, for which he introduced the term apparent weight as compared to

5712-610: The Greeks and a despot to the barbarians". Alexander's education under the guardianship of Aristotle likely lasted for only a few years, as at around the age of sixteen he returned to Pella and was appointed regent of Macedon by his father Philip. During this time, Aristotle is said to have gifted Alexander an annotated copy of the Iliad , which reportedly became one of Alexander's most prized possessions. Scholars speculate that two of Aristotle's now lost works, On kingship and On behalf of

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5824-771: The Persians, and philosophical questions, like the definition of braveness. A widespread speculation in antiquity suggested that Aristotle played a role in Alexander's death, but the only evidence of this is an unlikely claim made some six years after the death. Following Alexander's death, anti-Macedonian sentiment in Athens was rekindled. In 322 BC, Demophilus and Eurymedon the Hierophant reportedly denounced Aristotle for impiety, prompting him to flee to his mother's family estate in Chalcis, Euboea , at which occasion he

5936-491: The Soul and Poetics . Aristotle studied and made significant contributions to "logic, metaphysics, mathematics, physics, biology, botany, ethics, politics, agriculture, medicine, dance, and theatre." While Alexander deeply admired Aristotle, near the end of his life, the two men became estranged having diverging opinions over issues, like the optimal administration of city-states, the treatment of conquered populations, such as

6048-500: The acceleration due to gravity", thus distinguishing it from mass for official usage. In the 20th century, the Newtonian concepts of absolute time and space were challenged by relativity. Einstein's equivalence principle put all observers, moving or accelerating, on the same footing. This led to an ambiguity as to what exactly is meant by the force of gravity and weight. A scale in an accelerating elevator cannot be distinguished from

6160-432: The acceleration due to gravity. This resolution defines weight as a vector, since force is a vector quantity. However, some textbooks also take weight to be a scalar by defining: The weight W of a body is equal to the magnitude F g of the gravitational force on the body. The gravitational acceleration varies from place to place. Sometimes, it is simply taken to have a standard value of 9.80665 m/s , which gives

6272-513: The actual gravity or gravitas , which changed as the object fell. The concept of gravitas was eventually replaced by Jean Buridan 's impetus , a precursor to momentum . The rise of the Copernican view of the world led to the resurgence of the Platonic idea that like objects attract but in the context of heavenly bodies. In the 17th century, Galileo made significant advances in

6384-400: The actual gravity that would be experienced near the poles. Aristotle Aristotle ( Attic Greek : Ἀριστοτέλης , romanized:  Aristotélēs ; 384–322 BC) was an Ancient Greek philosopher and polymath . His writings cover a broad range of subjects spanning the natural sciences , philosophy , linguistics , economics , politics , psychology , and the arts . As

6496-494: The ball along to make it continue to rise even though the hand is no longer acting on it, resulting in the Medieval theory of impetus . Aristotle suggested that the reason for anything coming about can be attributed to four different types of simultaneously active factors. His term aitia is traditionally translated as "cause", but it does not always refer to temporal sequence; it might be better translated as "explanation", but

6608-463: The basic physical quantities and units in mechanics as a part of the International standard ISO/IEC 80000 , the definition of weight is given as: Definition Remarks The definition is dependent on the chosen frame of reference . When the chosen frame is co-moving with the object in question then this definition precisely agrees with the operational definition. If the specified frame

6720-399: The becoming is for the sake of the end; and the actuality is the end, and it is for the sake of this that the potentiality is acquired. For animals do not see in order that they may have sight, but they have sight that they may see. In summary, the matter used to make a house has potentiality to be a house and both the activity of building and the form of the final house are actualities, which

6832-475: The body, there exists an opposite and equal force by the support on the body. Also it is equal to the force exerted by the body on its support because action and reaction have same numerical value and opposite direction. This can make a considerable difference, depending on the details; for example, an object in free fall exerts little if any force on its support, a situation that is commonly referred to as weightlessness . However, being in free fall does not affect

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6944-574: The broad sense coextensive with reasoning, which he also would describe as "science". However, his use of the term science carries a different meaning than that covered by the term "scientific method". For Aristotle, "all science ( dianoia ) is either practical, poetical or theoretical" ( Metaphysics 1025b25). His practical science includes ethics and politics; his poetical science means the study of fine arts including poetry; his theoretical science covers physics, mathematics and metaphysics. In his On Generation and Corruption , Aristotle related each of

7056-433: The cause of earthquakes was a gas or vapor ( anathymiaseis ) that was trapped inside the earth and trying to escape, following other Greek authors Anaxagoras , Empedocles and Democritus . Aristotle also made many observations about the hydrologic cycle. For example, he made some of the earliest observations about desalination: he observed early – and correctly – that when seawater is heated, freshwater evaporates and that

7168-410: The composite natural ones, the study of nature would be the primary kind of knowledge; but if there is some motionless independent thing, the knowledge of this precedes it and is first philosophy, and it is universal in just this way , because it is first. And it belongs to this sort of philosophy to study being as being, both what it is and what belongs to it just by virtue of being. Aristotle examines

7280-504: The concept of weight. He proposed a way to measure the difference between the weight of a moving object and an object at rest. Ultimately, he concluded weight was proportionate to the amount of matter of an object, not the speed of motion as supposed by the Aristotelean view of physics. The introduction of Newton's laws of motion and the development of Newton's law of universal gravitation led to considerable further development of

7392-407: The concept of weight. Weight became fundamentally separate from mass . Mass was identified as a fundamental property of objects connected to their inertia , while weight became identified with the force of gravity on an object and therefore dependent on the context of the object. In particular, Newton considered weight to be relative to another object causing the gravitational pull, e.g. the weight of

7504-406: The concepts of substance ( ousia ) and essence ( to ti ên einai , "the what it was to be") in his Metaphysics (Book VII), and he concludes that a particular substance is a combination of both matter and form, a philosophical theory called hylomorphism . In Book VIII, he distinguishes the matter of the substance as the substratum , or the stuff of which it is composed. For example, the matter of

7616-478: The concepts of heaviness (weight) and lightness (levity) date back to the ancient Greek philosophers . These were typically viewed as inherent properties of objects. Plato described weight as the natural tendency of objects to seek their kin. To Aristotle , weight and levity represented the tendency to restore the natural order of the basic elements: air, earth, fire and water. He ascribed absolute weight to earth and absolute levity to fire. Archimedes saw weight as

7728-399: The data to come to the theory of evolution . Aristotle's writings can seem to modern readers close to implying evolution, but while Aristotle was aware that new mutations or hybridizations could occur, he saw these as rare accidents. For Aristotle, accidents, like heat waves in winter, must be considered distinct from natural causes. He was thus critical of Empedocles's materialist theory of

7840-455: The details of Aristotle's life are not well-established. The biographies written in ancient times are often speculative and historians only agree on a few salient points. Aristotle was born in 384 BC in Stagira , Chalcidice , about 55 km (34 miles) east of modern-day Thessaloniki . He was the son of Nicomachus , the personal physician of King Amyntas of Macedon , and Phaestis,

7952-491: The earliest study of formal logic, and his conception of it was the dominant form of Western logic until 19th-century advances in mathematical logic . Kant stated in the Critique of Pure Reason that with Aristotle, logic reached its completion. Most of Aristotle's work is probably not in its original form, because it was most likely edited by students and later lecturers. The logical works of Aristotle were compiled into

8064-500: The effect of the centrifugal force from the Earth's rotation. The operational definition, as usually given, does not explicitly exclude the effects of buoyancy , which reduces the measured weight of an object when it is immersed in a fluid such as air or water. As a result, a floating balloon or an object floating in water might be said to have zero weight. In the ISO International standard ISO 80000-4:2006, describing

8176-423: The effects of gravity: the weight is the quantity that is measured by, for example, a spring scale. Thus, in a state of free fall , the weight would be zero. In this sense of weight, terrestrial objects can be weightless: so if one ignores air resistance , one could say the legendary apple falling from the tree , on its way to meet the ground near Isaac Newton , was weightless. The unit of measurement for weight

8288-430: The expression sto pudov ( сто пудов ) – 'a hundred poods ,' an intentional play on the foreign "hundred percent" – imparts the ponderative sense of overwhelming weight to the declarative sentence it is added to. The generic meaning of "very serious" or "absolutely sure" has almost supplanted its original meaning of "very heavy weight." The adjective stopudovy and the adverb stopudovo are also used to convey

8400-407: The factory. When the scale is moved to another location on Earth, the force of gravity will be different, causing a slight error. So to be highly accurate and legal for commerce, spring scales must be re-calibrated at the location at which they will be used. A balance on the other hand, compares the weight of an unknown object in one scale pan to the weight of standard masses in the other, using

8512-442: The first century AD editor who assembled various small selections of Aristotle's works to create the treatise we know by the name Metaphysics . Aristotle called it "first philosophy", and distinguished it from mathematics and natural science (physics) as the contemplative ( theoretikē ) philosophy which is "theological" and studies the divine. He wrote in his Metaphysics (1026a16): If there were no other independent things besides

8624-533: The following. Brood size decreases with (adult) body mass, so that an elephant has fewer young (usually just one) per brood than a mouse. Lifespan increases with gestation period , and also with body mass, so that elephants live longer than mice, have a longer period of gestation, and are heavier. As a final example, fecundity decreases with lifespan, so long-lived kinds like elephants have fewer young in total than short-lived kinds like mice. Aristotle distinguished about 500 species of animals , arranging these in

8736-473: The force necessary to accelerate an object of one-pound mass at 1   ft/s , and is equivalent to about 1/32.2 of a pound- force . The slug is defined as the amount of mass that accelerates at 1   ft/s when one pound-force is exerted on it, and is equivalent to about 32.2 pounds (mass). The kilogram-force is a non-SI unit of force, defined as the force exerted by a one-kilogram mass in standard Earth gravity (equal to 9.80665 newtons exactly). The dyne

8848-531: The forms as existing separately from the things that participate in them, Aristotle maintained that universals exist within each thing on which each universal is predicated. So, according to Aristotle, the form of apple exists within each apple, rather than in the world of the forms. Concerning the nature of change ( kinesis ) and its causes, as he outlines in his Physics and On Generation and Corruption ( 319b–320a), he distinguishes coming-to-be ( genesis , also translated as 'generation') from: Coming-to-be

8960-571: The founder of the Peripatetic school of philosophy in the Lyceum in Athens , he began the wider Aristotelian tradition that followed, which set the groundwork for the development of modern science . Little is known about Aristotle's life. He was born in the city of Stagira in northern Greece during the Classical period . His father, Nicomachus , died when Aristotle was a child, and he

9072-515: The four elements proposed earlier by Empedocles , earth , water , air , and fire , to two of the four sensible qualities, hot, cold, wet, and dry. In the Empedoclean scheme, all matter was made of the four elements, in differing proportions. Aristotle's scheme added the heavenly aether , the divine substance of the heavenly spheres , stars and planets. Aristotle describes two kinds of motion: "violent" or "unnatural motion", such as that of

9184-428: The ground, say) require more force to make them move; and objects pushed with greater force move faster. This would imply the equation incorrect in modern physics. Natural motion depends on the element concerned: the aether naturally moves in a circle around the heavens, while the 4 Empedoclean elements move vertically up (like fire, as is observed) or down (like earth) towards their natural resting places. In

9296-639: The head of the Lyceum, who in turn passed them down to Neleus of Scepsis in Asia Minor. There, the papers remained hidden for protection until they were purchased by the collector Apellicon . In the meantime, many copies of Aristotle's major works had already begun to circulate and be used in the Lyceum of Athens, Alexandria , and later in Rome . With the Prior Analytics , Aristotle is credited with

9408-440: The image. According to Aristotle, spontaneity and chance are causes of some things, distinguishable from other types of cause such as simple necessity. Chance as an incidental cause lies in the realm of accidental things , "from what is spontaneous". There is also more a specific kind of chance, which Aristotle names "luck", that only applies to people's moral choices. In astronomy , Aristotle refuted Democritus 's claim that

9520-403: The local force of gravity can vary by up to 0.5% at different locations, spring scales will measure slightly different weights for the same object (the same mass) at different locations. To standardize weights, scales are always calibrated to read the weight an object would have at a nominal standard gravity of 9.80665   m/s (approx. 32.174   ft/s ). However, this calibration is done at

9632-468: The modern zoologist would call vertebrates as the hotter "animals with blood", and below them the colder invertebrates as "animals without blood". Those with blood were divided into the live-bearing ( mammals ), and the egg-laying ( birds , reptiles , fish ). Those without blood were insects, crustacea (non-shelled – cephalopods, and shelled ) and the hard-shelled molluscs ( bivalves and gastropods ). He recognised that animals did not exactly fit into

9744-433: The object by other objects in its environment, although there is some variation and debate as to the exact definition. Some standard textbooks define weight as a vector quantity, the gravitational force acting on the object. Others define weight as a scalar quantity, the magnitude of the gravitational force. Yet others define it as the magnitude of the reaction force exerted on a body by mechanisms that counteract

9856-437: The object would weigh at standard gravity, not the actual local force of gravity on the object. If the actual force of gravity on the object is needed, this can be calculated by multiplying the mass measured by the balance by the acceleration due to gravity – either standard gravity (for everyday work) or the precise local gravity (for precision work). Tables of the gravitational acceleration at different locations can be found on

9968-404: The oceans are then replenished by the cycle of rainfall and river runoff ("I have proved by experiment that salt water evaporated forms fresh and the vapor does not when it condenses condense into sea water again.") Aristotle was the first person to study biology systematically, and biology forms a large part of his writings. He spent two years observing and describing the zoology of Lesbos and

10080-400: The person is in motion, the result of any other forces acting on the body such as in the case of acceleration or deceleration of a lift, or centrifugal forces when turning sharply. Weight is commonly measured using one of two methods. A spring scale or hydraulic or pneumatic scale measures local weight, the local force of gravity on the object (strictly apparent weight force ). Since

10192-407: The poet Dante called him "the master of those who know". His works contain the earliest known formal study of logic, and were studied by medieval scholars such as Peter Abelard and Jean Buridan . Aristotle's influence on logic continued well into the 19th century. In addition, his ethics , although always influential, gained renewed interest with the modern advent of virtue ethics . In general,

10304-433: The same certainty as experimental science, but it sets out testable hypotheses and constructs a narrative explanation of what is observed. In this sense, Aristotle's biology is scientific. From the data he collected and documented, Aristotle inferred quite a number of rules relating the life-history features of the live-bearing tetrapods (terrestrial placental mammals) that he studied. Among these correct predictions are

10416-459: The same sense of certainty. The word is also used in Polish idiomatically or as a proverb (with the original/strict meaning commonly forgotten): nudy na pudy (Polish for 'unsupportable boredoms', literally 'boredoms [that could be measured] in poods ') Weight In science and engineering , the weight of an object is a quantity associated with the gravitational force exerted on

10528-439: The seed of a plant in the soil is potentially ( dynamei ) a plant, and if it is not prevented by something, it will become a plant. Potentially, beings can either 'act' ( poiein ) or 'be acted upon' ( paschein ), which can be either innate or learned. For example, the eyes possess the potentiality of sight (innate – being acted upon), while the capability of playing the flute can be possessed by learning (exercise – acting). Actuality

10640-706: The sights one viewed at the Mysteries, "to experience is to learn" ( παθεĩν μαθεĩν ). Aristotle remained in Athens for nearly twenty years before leaving in 348/47 BC after Plato's death. The traditional story about his departure records that he was disappointed with the Academy's direction after control passed to Plato's nephew Speusippus , although it is possible that the anti-Macedonian sentiments in Athens could have also influenced his decision. Aristotle left with Xenocrates to Assos in Asia Minor , where he

10752-756: The study of more complex forms, namely, syllogisms (in the Analytics ) and dialectics (in the Topics and Sophistical Refutations ). The first three treatises form the core of the logical theory stricto sensu : the grammar of the language of logic and the correct rules of reasoning. The Rhetoric is not conventionally included, but it states that it relies on the Topics . What is today called Aristotelian logic with its types of syllogism (methods of logical argument), Aristotle himself would have labelled "analytics". The term "logic" he reserved to mean dialectics . The word "metaphysics" appears to have been coined by

10864-446: The surface of the Sun, the Earth's moon, each of the planets in the solar system. The "surface" is taken to mean the cloud tops of the giant planets (Jupiter, Saturn, Uranus, and Neptune). For the Sun, the surface is taken to mean the photosphere . The values in the table have not been de-rated for the centrifugal effect of planet rotation (and cloud-top wind speeds for the giant planets) and therefore, generally speaking, are similar to

10976-422: The surface of the Moon , an object can have a significantly different weight than on Earth. The gravity on the surface of the Moon is only about one-sixth as strong as on the surface of the Earth. A one-kilogram mass is still a one-kilogram mass (as mass is an intrinsic property of the object) but the downward force due to gravity, and therefore its weight, is only one-sixth of what the object would have on Earth. So

11088-558: The surrounding seas, including in particular the Pyrrha lagoon in the centre of Lesbos. His data in History of Animals , Generation of Animals , Movement of Animals , and Parts of Animals are assembled from his own observations, statements given by people with specialized knowledge, such as beekeepers and fishermen, and less accurate accounts provided by travellers from overseas. His apparent emphasis on animals rather than plants

11200-401: The teaching community as how to define weight for their students, choosing between a nominal definition of weight as the force due to gravity or an operational definition defined by the act of weighing. Several definitions exist for weight , not all of which are equivalent. The most common definition of weight found in introductory physics textbooks defines weight as the force exerted on

11312-475: The time of Homer , and "the upheaving of one of the Aeolian islands , previous to a volcanic eruption ."' Meteorologica lends its name to the modern study of meteorology, but its modern usage diverges from the content of Aristotle's ancient treatise on meteors . The ancient Greeks did use the term for a range of atmospheric phenomena, but also for earthquakes and volcanic eruptions. Aristotle proposed that

11424-478: The traditional rendering will be employed here. Aristotle describes experiments in optics using a camera obscura in Problems , book 15. The apparatus consisted of a dark chamber with a small aperture that let light in. With it, he saw that whatever shape he made the hole, the sun's image always remained circular. He also noted that increasing the distance between the aperture and the image surface magnified

11536-413: The unknown object and standard masses in the scale pans. In the absence of a gravitational field, away from planetary bodies (e.g. space), a lever-balance would not work, but on the Moon, for example, it would give the same reading as on Earth. Some balances are marked in weight units, but since the weights are calibrated at the factory for standard gravity, the balance will measure standard weight, i.e. what

11648-431: The variation of acceleration due to gravity (and hence the variation of weight) at various locations on the Earth's surface. The historical use of "weight" for "mass" also persists in some scientific terminology – for example, the chemical terms "atomic weight", "molecular weight", and "formula weight", can still be found rather than the preferred " atomic mass ", etc. In a different gravitational field, for example, on

11760-413: The various concepts of weight have to do with the theory of relativity according to which gravity is modeled as a consequence of the curvature of spacetime . In the teaching community, a considerable debate has existed for over half a century on how to define weight for their students. The current situation is that a multiple set of concepts co-exist and find use in their various contexts. Discussion of

11872-405: The web. Gross weight is a term that is generally found in commerce or trade applications, and refers to the total weight of a product and its packaging. Conversely, net weight refers to the weight of the product alone, discounting the weight of its container or packaging; and tare weight is the weight of the packaging alone. The table below shows comparative gravitational accelerations at

11984-404: The weight according to the gravitational definition. Therefore, the operational definition is sometimes refined by requiring that the object be at rest. However, this raises the issue of defining "at rest" (usually being at rest with respect to the Earth is implied by using standard gravity ). In the operational definition, the weight of an object at rest on the surface of the Earth is lessened by

12096-584: Was brought up by a guardian. At around eighteen years old, he joined Plato 's Academy in Athens and remained there until the age of thirty seven ( c.  347 BC ). Shortly after Plato died, Aristotle left Athens and, at the request of Philip II of Macedon , tutored his son Alexander the Great beginning in 343 BC. He established a library in the Lyceum, which helped him to produce many of his hundreds of books on papyrus scrolls . Though Aristotle wrote many treatises and dialogues for publication, only around

12208-413: Was invited by his former fellow student Hermias of Atarneus ; he stayed there for a few years and left around the time of Hermias' death. While at Assos, Aristotle and his colleague Theophrastus did extensive research in botany and marine biology , which they later continued at the near-by island of Lesbos . During this time, Aristotle married Pythias , Hermias's adoptive daughter and niece, and had

12320-523: Was said to have stated "I will not allow the Athenians to sin twice against philosophy" – a reference to Athens's trial and execution of Socrates . He died in Chalcis, Euboea of natural causes later that same year, having named his student Antipater as his chief executor and leaving a will in which he asked to be buried next to his wife. Aristotle left his works to Theophrastus, his successor as

12432-435: Was the direct cause of the falling motion of an object, the speed of the falling object was supposed to be directly proportionate to the weight of the object. As medieval scholars discovered that in practice the speed of a falling object increased with time, this prompted a change to the concept of weight to maintain this cause-effect relationship. Weight was split into a "still weight" or pondus , which remained constant, and

12544-588: Was widely disbelieved until the 19th century. He gives accurate descriptions of the four-chambered fore-stomachs of ruminants , and of the ovoviviparous embryological development of the hound shark . He notes that an animal's structure is well matched to function so birds like the heron (which live in marshes with soft mud and live by catching fish) have a long neck, long legs, and a sharp spear-like beak, whereas ducks that swim have short legs and webbed feet. Darwin , too, noted these sorts of differences between similar kinds of animal, but unlike Aristotle used

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