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Computer Screens Harder To Understand, Less Persuasive
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- Computer operations.
- Curation by Algorithm
- Texts for physics in english for high school Physical quantities and measurements
- 2. Mechanics Kinematics
- Conservation law In physics, a conservation law
- Oscillation and Wave
- 3. Thermal Physics Molecular physics
- Термодинамика
- 4.Electricity and magnetism Alternating current
Computer Screens Harder To Understand, Less Persuasive WASHINGTON Students who read essays on a computer screen found the text harder to understand, less interesting and less persuasive than students who read the same essay on paper, a new study has found. Researchers had 131 undergraduate students read two articles that had appeared in Time magazine - some read from the magazine, some read the exact same text after it had been scanned into a computer. "We were surprised that students found paper texts easier to understand and somewhat more convincing," said P. Karen Murphy, co-author of the study and assistant professor of educational psychology at Ohio State University. "It may be that students need to learn different processing abilities when they are attempting to read computerized text." Murphy said the results of this preliminary study cast doubt on the assumption that computerized texts are essentially more interesting and, thus, more likely to enhance learning. "Given that there is such an emphasis on using computers in the classroom, this study gives educators reason to pause and examine the supposed benefits associated with computer use in classrooms," she said. "This study provides a first step toward understanding how computers might influence the learning process." Murphy conducted the study with Ohio State graduate students Joyce Long, Theresa Holleran and Elizabeth Esterly. They presented their results Aug. 5 in Washington at the annual meeting of the American Psychological Association. 353 The study involved 64 men and 67 women, all undergraduates at Ohio State. The students read two essays that had appeared in Time, one involving doctor-assisted suicide for terminally ill patients and the other about school integration. Before they read the essays, the students completed questionnaires analyzing their knowledge and beliefs about the subjects in the texts. After the readings, the students completed questionnaires that probed their understanding of the essays and also asked them about how persuasive and interesting they thought the essays were. One-third of the students read the print essays and responded to the questionnaires on paper. One-third read the essays on a computer and then responded to the questionnaire on paper. The final third of participants read the essays on the computer screens and responded to the questionnaire online. The results showed that students in all three groups increased their knowledge after reading the texts, and the beliefs of students in each group became more closely aligned with the authors. However, there were important differences, such as the fact that students who read the essays on the computer screen found the texts more difficult to understand. This was true regardless of how much computer experience the students reported. "In some ways, this is surprising because the computerized essays were the exact same text, presenting the exact same information," Murphy said. The computerized texts even included the small picture that appeared in the print edition. "There is no reason they should be harder to understand. But we think readers develop strategies about how to remember and comprehend printed texts, but these students were unable to transfer those strategies to computerized texts." The students found the computerized texts less interesting than printed text, which should be expected if they didn't understand the computerized versions as well, she said. Students who read the essays online also rated the authors as less credible and the arguments as less persuasive. "Again, it may be that if these students did not understand the message, they would not judge the author to be as credible and might not find the arguments as persuasive." There were no significant differences between the students who read the texts online and responded to the questionnaires on paper, and those who read the online texts and also responded to the questions online. Murphy said that if the college students in this study had difficulty understanding computerized text, such text may present additional hurdles for less competent readers. "We shouldn't make it more difficult for children to learn, which is why we need to be careful about how we use computers in the classroom," she said. "A lot of questions have to be answered before we continue further into making computers part of the curriculum." Story Source: The above post is reprinted from materials provided by Ohio State University. Computer operations. 354
Much of the processing computers can be divided into two general types of operation. Arithmetic procedures. Early computers performed mostly arithmetic operations, which gave the false impression that only engineers and scientists could benefit from computers .Of equal importance is the computers operations are computations with numbers such as addition, subtraction, and other mathematical ability to compare two values to determine if one is larger than, smaller than, or equal to the other. This is called a logical operation .The comparison may take place between numbers, letters, sounds, or even drawings The processingofthe computer is based on the computer’sability to perform logical and arithmetical operations. Instructions must be given to the computer to tell it how to process the data it receives and the format needed for output and storage. The ability to follow the program sets computers apart from most tools. However, new tools ranging from typewriters to microwave ovens have embedded computers, or build-in computers .An embedded computer can accept data to use several options in it’s program, but the program itself cannot be changed. This makes these devices flexible and convenient but not the embedded computers itself. Curation by Algorithm Tarleton Gillespie Social media and content-sharing platforms must regularly make decisions about what can be said and done on their sites, extending centuries-old debates about the proper boundaries of public expression into the digital era. But, in addition, the particular ways in which these sites enforce these choices have their own consequences. While some providers depend on editorially managing content, or lean on their user community to govern for them, some are beginning to employ algorithmic means of managing their archive, so offending content can be procedurally and automatically removed, or kept from some users and not others. Curation by algorithm raises new questions about what judgments are being made, whose values are being inscribed into the technical infrastructure, and what a dependence on these tools might mean for the contours of public discourse and users' participation in it. 355
Texts for physics in english for high school Physical quantities and measurements Speaking A physical quantity (or "physical magnitude") is a physical property of a phenomenon, body, or substance, that can be quantified bymeasurement.[1] A physical quantity can be expressed as the combination of a number – usually a real number – and a unit or combination of units; for example, 1.6749275×10−27 kg (the mass of the neutron), or 299792458 metres per second (the speed of light). Physical quantities are measured as 'nu' where n is the number and u is the unit. For example: A boy measured the length of a room as 3m. Here 3 is the number and m(metre) is the unit. 3m can also be written as 300cm. This shows that n1u1 =n2u2. Almost all matters have quantity. 2. Mechanics Kinematics Kinematics is used in astrophysics to describe the motion of celestial bodies and collections of such bodies. In mechanical engineering, robotics, and biomechanics[7] kinematics is used to describe the motion of systems composed of joined parts (multi-link systems) such as an engine, a robotic arm or the skeleton of the human body. The use of geometric transformations, also called rigid transformations, to describe the movement of components of a mechanical system simplifies the derivation of its equations of motion, and is central to dynamic analysis. Kinematic analysis is the process of measuring the kinematic quantities used to describe motion. In engineering, for instance, kinematic analysis may be used to find the range of movement for a given mechanism, and working in reverse, using kinematic synthesis used to design a mechanism for a desired range of motion.[8] In addition, kinematics applies algebraic geometry to the study of the mechanical advantage of a mechanical system or mechanism. Dynamics The study of dynamics falls under two categories: linear and rotational. Linear dynamics pertains to objects moving in a line and involves such quantities as force, mass/inertia,displacement (in units of distance), velocity (distance per unit time), acceleration (distance per unit of time squared) and momentum (mass times unit of velocity). Rotational dynamics pertains to objects that are rotating or moving in a curved path and involves such quantities as torque, moment of inertia/rotational inertia, angular displacement (in radians or less often, degrees), angular velocity (radians per unit time), angular acceleration (radians per unit of time squared) and angular momentum (moment of inertia times unit of angular velocity). Very often, objects exhibit linear and rotational motion. For classical electromagnetism, it is Maxwell's equations that describe the dynamics. And the dynamics of classical systems involving both mechanics and 356
electromagnetism are described by the combination of Newton's laws, Maxwell's equations, and the Lorentz force. Conservation law In physics, a conservation law states that a particular measurable property of an isolated physical system does not change as the system evolves over time. Exact conservation laws include conservation of energy, conservation of linear momentum, conservation of angular momentum, and conservation of electric charge. There are also many approximate conservation laws, which apply to such quantities as mass,parity, lepton number, baryon number, strangeness, hypercharge, etc. These quantities are conserved in certain classes of physics processes, but not in all. A local conservation law is usually expressed mathematically as a continuity equation, a partial differential equation which gives a relation between the amount of the quantity and the "transport" of that quantity. It states that the amount of the conserved quantity at a point or within a volume can only change by the amount of the quantity which flows in or out of the volume. From Noether's theorem, each conservation law is associated with a symmetry in the underlying physics. Oscillation and Wave The harmonic oscillator and the systems it models have a single degree of freedom. More complicated systems have more degrees of freedom, for example two masses and three springs (each mass being attached to fixed points and to each other). In such cases, the behavior of each variable influences that of the others. This leads to a coupling of the oscillations of the individual degrees of freedom. For example, two pendulum clocks (of identical frequency) mounted on a common wall will tend to synchronise. This phenomenon was first observed by Christiaan Huygens in 1665. The apparent motions of the compound oscillations typically appears very complicated but a more economic, computationally simpler and conceptually deeper description is given by resolving the motion into normal modes. More special cases are the coupled oscillators where energy alternates between two forms of oscillation. Well -known is the Wilberforce pendulum, where the oscillation alternates between an elongation of a vertical spring and the rotation of an object at the end of that spring. A single, all-encompassing definition for the term wave is not straightforward. A vibration can be defined as a back-and-forthmotion around a reference value. However, a vibration is not necessarily a wave. An attempt to define the necessary and sufficient characteristics that qualify a phenomenon to be called a wave results in a fuzzy border line. The term wave is often intuitively understood as referring to a transport of spatial disturbances that are generally not accompanied by a motion of the medium occupying this space as a whole. In a wave, the energy of a vibration is moving away from the source in the form of a disturbance within the surrounding medium (Hall 1980, p. 8). However, this motion is problematic for a standing wave (for example, a wave on a string), where energy is moving in both directions equally, or for electromagnetic (e.g., light) waves in a vacuum, where the concept of medium does not apply and interaction with a target is the key to wave detection and practical 357
applications. There are water waves on the ocean surface; gamma waves and light waves emitted by the Sun; microwaves used in microwave ovens and in radar equipment; radio waves broadcast by radio stations; and sound waves generated by radio receivers, telephone handsets and living creatures (as voices), to mention only a few wave phenomena. It may appear that the description of waves is closely related to their physical origin for each specific instance of a wave process. For example, acoustics is distinguished fromoptics in that sound waves are related to a mechanical rather than an electromagnetic wave transfer caused by vibration. Concepts such as mass, momentum, inertia, orelasticity, become therefore crucial in describing acoustic (as distinct from optic) wave processes. This difference in origin introduces certain wave characteristics particular to the properties of the medium involved. For example, in the case of air: vortices, radiation pressure, shock waves etc.; in the case of solids: Rayleigh waves, dispersion; and so on.... Other properties, however, although usually described in terms of origin, may be generalized to all waves. For such reasons, wave theory represents a particular branch ofphysics that is concerned with the properties of wave processes independently of their physical origin.[1] For example, based on the mechanical origin of acoustic waves, a moving disturbance in space–time can exist if and only if the medium involved is neither infinitely stiff nor infinitely pliable. If all the parts making up a medium were rigidly bound , then they would all vibrate as one, with no delay in the transmission of the vibration and therefore no wave motion. On the other hand, if all the parts were independent, then there would not be any transmission of the vibration and again, no wave motion. Although the above statements are meaningless in the case of waves that do not require a medium, they reveal a characteristic that is relevant to all waves regardless of origin: within a wave, the phase of a vibration (that is, its position within the vibration cycle) is different for adjacent points in space because the vibration reaches these points at different times. 3. Thermal Physics Molecular physics Molecular mechanics is one aspect of molecular modelling, as it refers to the use of classical mechanics/Newtonian mechanics to describe the physical basis behind the models. Molecular models typically describe atoms (nucleus and electrons collectively) as point charges with an associated mass. The interactions between neighbouring atoms are described by spring-like interactions (representing chemical bonds) and van der Waals forces. The Lennard-Jones potential is commonly used to describe van der Waals forces. The electrostatic interactions are computed based onCoulomb's law. Atoms are assigned coordinates in Cartesian space or in internal coordinates, and can also be assigned velocities in dynamical simulations. The atomic velocities are related to the temperature of the system, a macroscopic quantity. The collective mathematical expression is known as a potential function and is related to the system internal energy (U), a thermodynamic quantity equal to the sum of potential and kinetic energies. Methods which minimize the potential energy are 358
known as energy minimization techniques (e.g., steepest descent and conjugate gradient), while methods that model the behaviour of the system with propagation of time are known as molecular dynamics. This function, referred to as a potential function, computes the molecular potential energy as a sum of energy terms that describe the deviation of bond lengths, bond angles and torsion angles away from equilibrium values, plus terms for non-bonded pairs of atoms describing van der Waals and electrostatic interactions. The set of parameters consisting of equilibrium bond lengths, bond angles, partial charge values, force constants and van der Waals parameters are collectively known as a force field. Different implementations of molecular mechanics use different mathematical expressions and different parameters for the potential function. The common force fields in use today have been developed by using high level quantum calculations and/or fitting to experimental data. The technique known as energy minimization is used to find positions of zero gradient for all atoms, in other words, a local energy minimum. Lower energy states are more stable and are commonly investigated because of their role in chemical and biological processes. Amolecular dynamics simulation, on the other hand, computes the behaviour of a system as a function of time. It involves solving Newton's laws of motion, principally the second law, . Integration of Newton's laws of motion, using different integration algorithms, leads to atomic trajectories in space and time. The force on an atom is defined as the negative gradient of the potential energy function. The energy minimization technique is useful for obtaining a static picture for comparing between states of similar systems, while molecular dynamics provides information about the dynamic processes with the intrinsic inclusion of temperature effects. Термодинамика The history of thermodynamics as a scientific discipline generally begins with Otto von Guericke who, in 1650, built and designed the world's first vacuum pump and demonstrated a vacuum using his Magdeburg hemispheres. Guericke was driven to make a vacuum in order to disprove Aristotle's long-held supposition that 'nature abhors a vacuum'. Shortly after Guericke, the English physicist and chemist Robert Boyle had learned of Guericke's designs and, in 1656, in coordination with English scientist Robert Hooke, built an air pump.[17] Using this pump, Boyle and Hooke noticed a correlation between pressure, temperature, and volume. In time, Boyle's Law was formulated, which states that pressure and volume are inversely proportional. Then, in 1679, based on these concepts, an associate of Boyle's named Denis Papinbuilt a steam digester, which was a closed vessel with a tightly fitting lid that confined steam until a high pressure was generated. Later designs implemented a steam release valve that kept the machine from exploding. By watching the valve rhythmically move up and down, Papin conceived of the idea of a piston and a cylinder engine. He did not, however, follow through with his design. Nevertheless, in 1697, based on Papin's designs, engineer Thomas Savery built the first engine, followed by Thomas Newcomen in 1712. Although 359
these early engines were crude and inefficient, they attracted the attention of the leading scientists of the time. The fundamental concepts of heat capacity and latent heat, which were necessary for the development of thermodynamics, were developed by Professor Joseph Black at the University of Glasgow, where James Watt was employed as an instrument maker. Black and Watt performed experiments together, but it was Watt who conceived the idea of the external condenser which resulted in a large increase in steam engineefficiency.[18] Drawing on all the previous work led Sadi Carnot, the "father of thermodynamics", to publish Reflections on the Motive Power of Fire (1824), a discourse on heat, power, energy and engine efficiency. The paper outlined the basic energetic relations between the Carnot engine, the Carnot cycle, and motive power. It marked the start of thermodynamics as a modern science.[10] The first thermodynamic textbook was written in 1859 by William Rankine, originally trained as a physicist and a civil and mechanical engineering professor at the University of Glasgow.[19] The first and second laws of thermodynamics emerged simultaneously in the 1850s, primarily out of the works of William Rankine, Rudolf Clausius, and William Thomson (Lord Kelvin). The foundations of statistical thermodynamics were set out by physicists such as James Clerk Maxwell, Ludwig Boltzmann, Max Planck,Rudolf Clausius and J. Willard Gibbs. During the years 1873-76 the American mathematical physicist Josiah Willard Gibbs published a series of three papers, the most famous being On the Equilibrium of Heterogeneous Substances ,[3] in which he showed how thermodynamic processes, including chemical reactions, could be graphically analyzed, by studying the energy, entropy, volume, temperature and pressure of the thermodynamic system in such a manner, one can determine if a process would occur spontaneously.[20] Also Pierre Duhem in the 19th century wrote about chemical thermodynamics.[4] During the early 20th century, chemists such as Gilbert N. Lewis, Merle Randall,[5] and E. A. Guggenheim[6][7] applied the mathematical methods of Gibbs to the analysis of chemical processes. 4.Electricity and magnetism Alternating current The first alternator to produce alternating current was a dynamo electric generator based on Michael Faraday's principles constructed by the French instrument maker Hippolyte Pixii in 1832.[4] Pixii later added a commutator to his device to produce the (then) more commonly used direct current. The earliest recorded practical application of alternating current is by Guillaume Duchenne, inventor and developer of electrotherapy. In 1855, he announced that AC was superior to direct current for electrotherapeutic triggering of muscle contractions.[5] Alternating current technology had first developed in Europe due to the work of Guillaume Duchenne (1850s), The Hungarian Ganz Works (1870s), Sebastian Ziani de Ferranti(1880s), Lucien Gaulard, and Galileo Ferraris. In 1876, Russian engineer Pavel Yablochkov invented a lighting system based 360
on a set of induction coils where the primary windings were connected to a source of AC. The secondary windings could be connected to several 'electric candles' (arc lamps) of his own design.[6][7] The coils Yablochkov employed functioned essentially as transformers.[6] In 1878, the Ganz factory, Budapest, Hungary, began manufacturing equipment for electric lighting and, by 1883, had installed over fifty systems in Austria-Hungary. Their AC systems used arc and incandescent lamps, generators, and other equipment.[8] A power transformer developed by Lucien Gaulard and John Dixon Gibbs was demonstrated in London in 1881, and attracted the interest of Westinghouse. They also exhibited the invention in Turin in 1884. In the autumn of 1884, Károly Zipernowsky, Ottó Bláthy and Miksa Déri (ZBD), three engineers associated with the Ganz factory, determined that open-core devices were impractical, as they were incapable of reliably regulating voltage.[11] In their joint 1885 patent applications for novel transformers (later called ZBD transformers), they described two designs with closed magnetic circuits where copper windings were either a) wound around iron wire ring core or b) surrounded by iron wire core.[10] In both designs, the magnetic flux linking the primary and secondary windings traveled almost entirely within the confines of the iron core, with no intentional path through air (see Toroidal cores below). The new transformers were 3.4 times more efficient than the open-core bipolar devices of Gaulard and Gibbs.[12] The Ganz factory in 1884 shipped the world's first five high-efficiency AC transformers.[13] This first unit had been manufactured to the following specifications: 1,400 W, 40 Hz, 120:72 V, 11.6:19.4 A, ratio 1.67:1, one-phase, shell form.[13] The ZBD patents included two other major interrelated innovations: one concerning the use of parallel connected, instead of series connected, utilization loads, the other concerning the ability to have high turns ratio transformers such that the supply network voltage could be much higher (initially 1,400 to 2,000 V) than the voltage of utilization loads (100 V initially preferred).[14][15] When employed in parallel connected electric distribution systems, closed-core transformers finally made it technically and economically feasible to provide electric power for lighting in homes, businesses and public spaces.[16][17] The other essential milestone was the introduction of 'voltage source, voltage intensive' (VSVI) systems'[18] by the invention of constant voltage generators in 1885.[19] Ottó Bláthy also invented the first AC electricity meter.[20][21][22][23] The AC power systems was developed and adopted rapidly after 1886 due to its ability to distribute electricity efficiently over long distances, overcoming the limitations of thedirect current system. In 1886, the ZBD engineers designed, and the Ganz factory supplied electrical equipment for, the world's first power station that used AC generators to power a parallel connected common electrical network, the steam-powered Rome-Cerchi power plant.[24] The reliability of the AC technology received impetus after the Ganz Works electrified a large European metropolis: Rome in 1886.[24] 361
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