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DEFINITION OF ENGINEERING
Engineering is the application of science to the optimum conversion ofthe resources of nature to the uses of humankind. The field has beendefined by the Engineers Council for Professional Development, in theUnited States, as the creative application of scientific principles todesign or develop structures, machines, apparatus, or manufacturingprocesses, or works utilizing them singly or in combination; or toconstruct or operate the same with full cognizance of their design; orto forecast their behavior under specific operating conditions; all asrespects an intended function, economics of operation and safety tolife and property. The term engineering is sometimes more looselydefined, especially in Great Britain, as the manufacture or assembly of
engines, machine tools, and machine parts.
The words engine and ingenious are derived from the same Latin root,ingenerare, which means to create. The early English verb enginemeant to contrive. Thus the engines of war were devices such ascatapults, floating bridges, and assault towers; their designer was theengine-er, or military engineer. The counterpart of the militaryengineer was the civil engineer, who applied essentially the sameknowledge and skills to designing buildings, streets, water supplies,sewage systems, and other projects.
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Associated with engineering is a great body of special knowledge;preparation for professional practice involves extensive training in the
application of that knowledge. Standards of engineering practice aremaintained through the efforts of professional societies, usuallyorganized on a national or regional basis, with each memberacknowledging a responsibility to the public over and aboveresponsibilities to his employer or to other members of his society.
The function of the scientist is to know, while that of the engineer is todo. The scientist adds to the store of verified, systematized knowledgeof the physical world; the engineer brings this knowledge to bear onpractical problems.
Engineering is based principally on physics, chemistry, andmathematics and their extensions into materials science, solid andfluid mechanics, thermodynamics, transfer and rate processes, andsystems analysis.
Unlike the scientist, the engineer is not free to select the problem thatinterests him; he must solve problems as they arise; his solution mustsatisfy conflicting requirements. Usually efficiency costs money;safety adds to complexity; improved performance increases weight.The engineering solution is the optimum solution, the end result that,taking many factors into account, is most desirable.
It may be the most reliable within a given weight limit, the simplestthat will satisfy certain safety requirements, or the most efficient for agiven cost. In many engineering problems the social costs aresignificant.
Engineers employ two types of natural resourcesmaterials andenergy. Materials are useful because of their properties: theirstrength, ease of fabrication, lightness, or durability; their ability toinsulate or conduct; their chemical, electrical, or acoustical properties.Important sources of energy include fossil fuels (coal, petroleum,
gas), wind, sunlight, falling water, and nuclear fission. Since mostresources are limited, the engineer must concern himself with thecontinual development of new resources as well as the efficientutilization of existing ones.
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HISTORY OF ENGINEERING
The first engineer known by name and achievement is Imhotep,builder of the Step Pyramid at aqqrah, Egypt, probably in about2550 bc. Imhoteps successorsEgyptian, Persian, Greek, and Romancarried civil engineering to remarkable heights on the basis ofempirical methods aided by arithmetic, geometry, and a smatteringof physical science. The Pharos (lighthouse) of Alexandria,Solomons Temple in Jerusalem, the Colosseum in Rome, the Persianand Roman road systems, the Pont du Gard aqueduct in France, andmany other large structures, some of which endure to this day, testify
to their skill, imagination, and daring. Of many treatises written bythem, one in particular survives to provide a picture of engineeringeducation and practice in classical times: VitruviusDe architectura,published in Rome in the 1st century ad, a 10-volume work coveringbuilding materials, construction methods, hydraulics, measurement,and town planning.
In construction medieval European engineers carried technique, in theform of the Gothic arch and flying buttress, to a height unknown tothe Romans. The sketchbook of the 13th-century French engineerVillard de Honnecourt reveals a wide knowledge of mathematics,geometry, natural and physical science, and draftsmanship.
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In Asia, engineering had a separate but very similar development,
with more and more sophisticated techniques of construction,hydraulics, and metallurgy helping to create advanced civilizationssuch as the Mongol empire, whose large, beautiful cities impressedMarco Polo in the 13th century.
Civil engineering emerged as a separate discipline in the 18thcentury, when the first professional societies and schools ofengineering were founded. Civil engineers of the 19th century builtstructures of all kinds, designed water-supply and sanitation systems,laid out railroad and highway networks, and planned cities. Englandand Scotland were the birthplace ofmechanical engineering, as a
derivation of the inventions of the Scottish engineer James Watt andthe textile machinists of the Industrial Revolution. The developmentof the British machine-tool industry gave tremendous impetus to thestudy of mechanical engineering both in Britain and abroad.
The growth of knowledge of electricityfrom Alessandro Voltasoriginal electric cell of 1800 through the experiments of Michael
Faraday and others, culminating in 1872 in the Gramme dynamoand electric motor (named after the Belgian Z.T. Gramme)led tothe development of electrical and electronics engineering. Theelectronics aspect became prominent through the work of suchscientists asJames Clerk Maxwell of Britain and Heinrich Hertz ofGermany in the late 19th century. Major advances came with thedevelopment of the vacuum tube by Lee De Forest of the UnitedStates in the early 20th century and the invention of the transistor in
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the mid-20th century. In the late 20th century electrical andelectronics engineers outnumbered all others in the world.
Chemical engineering grew out of the 19th-century proliferation ofindustrial processes involving chemical reactions in metallurgy,food, textiles, and many other areas. By 1880 the use of chemicals inmanufacturing had created an industry whose function was the massproduction of chemicals. The design and operation of the plants ofthis industry became a function of the chemical engineer.
Engineering functions
Problem solving is common to all engineering work. The problem mayinvolve quantitative or qualitative factors; it may be physical oreconomic; it may require abstract mathematics or common sense.Of great importance is the process of creative synthesis or design,putting ideas together to create a new and optimum solution.
Although engineering problems vary in scope and complexity, thesame general approach is applicable. First comes an analysis of thesituation and a preliminary decision on a plan of attack. In line withthis plan, the problem is reduced to a more categorical question thatcan be clearly stated. The stated question is then answered by
deductive reasoning from known principles or by creative synthesis,as in a new design. The answer or design is always checked foraccuracy and adequacy. Finally, the results for the simplified problemare interpreted in terms of the original problem and reported in anappropriate form.
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In order of decreasing emphasis on science, the major functions of all
engineering branches are the following:
Research. Using mathematical and scientific concepts,experimental techniques, and inductive reasoning, the researchengineer seeks new principles and processes.
Development. Development engineers apply the results ofresearch to useful purposes. Creative application of new knowledgemay result in a working model of a new electrical circuit, a chemicalprocess, or an industrial machine.
Design. In designing a structure or a product, the engineer selectsmethods, specifies materials, and determines shapes to satisfytechnical requirements and to meet performance specifications.
Construction. The construction engineer is responsible forpreparing the site, determining procedures that will economically andsafely yield the desired quality, directing the placement of materials,and organizing the personnel and equipment.
Production. Plant layout and equipment selection are theresponsibility of the production engineer, who chooses processes and
tools, integrates the flow of materials and components, and providesfor testing and inspection.
Operation. The operating engineer controls machines, plants, andorganizations providing power, transportation, and communication;determines procedures; and supervises personnel to obtain reliableand economic operation of complex equipment.
Management and other functions. In some countries andindustries, engineers analyze customers requirements, recommendunits to satisfy needs economically, and resolve related problems.
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TYPES OF ENGINEERING
CHEMICAL ENGINEERING
It consists on the development of processes and the design andoperation of plants in which materials undergo changes in theirphysical or chemical state. Applied throughout the process industries,it is founded on the principles of chemistry, physics, and mathematics.The laws ofphysical chemistry and physics govern the practicabilityand efficiency of chemical engineering operations. Energy changes,deriving from thermodynamic considerations, are particularlyimportant. Mathematics is a basic tool in optimization and modeling.
Optimization means arranging materials, facilities, and energy to yieldas productive and economical an operation as possible. Modeling isthe construction of theoretical mathematical prototypes of complexprocess systems, commonly with the aid of computers.
Chemical engineers are employed in the design and development ofboth processes and plant items. In each case, data and predictionsoften have to be obtained or confirmed with pilot experiments. Plantoperation and control is increasingly the sphere of the chemicalengineer rather than the chemist. Chemical engineering provides anideal background for the economic evaluation of new projects and, inthe plant construction sector, for marketing.
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CIVIL ENGINEERING
It is the profession of designing and executing structural works thatserve the general public. The term was first used in the 18th centuryto distinguish the newly recognized profession from militaryengineering, until then preeminent. From earliest times, however,engineers have engaged in peaceful activities, and many of the civilengineering works of ancient and medieval timessuch as the Romanpublic baths, roads, bridges, and aqueducts; the Flemish canals; theDutch sea defenses; the French Gothic cathedrals; and many othermonumentsreveal a history of inventive genius and persistentexperimentation.
The functions of the civil engineer can be divided into threecategories: those performed before construction (feasibility studies,site investigations, and design), those performed during construction(dealing with clients, consulting engineers, and contractors), andthose performed after construction (maintenance and research).
SCIENCE AND SYSTEMS ENGINEERING
Computer engineering involves many aspects of computer design,
the creation of individual components for computer equipment,networking design, and integrating software options with thehardware that will drive the applications. A competent computerengineer can secure work in any environment where computers play arole in the operation of the business. Because a computer engineerwill have an extensive understanding of such electronic devices asmicroprocessors, local and wide area networks, and evensupercomputers that form the basis for worldwide communications,the career paths are wide and varied. Computer engineers can findwork in such fields as telecommunications, transportation,manufacturing, and product development.
Some of the common tasks associated with the computer engineerinclude software design that is customized for a particular industrytype. Operating systems that are peculiar to the culture of a givencompany often require the input of a computer engineer, ensuringthat the functionality of the custom design meets all the needs of theapplication. In general, a computer engineer is not only part of thedesign process of a new application, but also continues to provide
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service and support as new versions of software are released, and inimplementing additional customizations or fixes to existing software.
One area where opportunities are expanding for qualified computerengineers is in the roboticsindustry. The unique skills ofthe computer engineer ishelping to move roboticsforward, by making the bestuse of traditional electronictechnology and the latest incomputer generatedapplications. The computer
engineer can find significantopportunities within robotic sto purse the design of newmotors, improved communication devices, and more sensitive sensorsthat can help robotic equipment function more efficiently.
ELECTRIC AND ELECTRONICS ENGINEERING
Electric engineering is the branch of engineering concerned with thepractical applications ofelectricity in all its forms, including those of
the field of electronics. Electronics engineering is that branch ofelectrical engineering concerned with the uses of theelectromagnetic spectrum and with the application of suchelectronic devices as integrated circuits, transistors, and vacuumtubes.
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In engineering practice, the distinction between electrical engineering
and electronics is based on the comparative strength of the electriccurrents used. In this sense, electrical engineering is the branchdealing with heavy currentthat is, electric light and power systemsand apparatuseswhereas electronics engineering deals with suchlight current applications as wire and radio communication, thestored-program electronic computer, radar, and automatic controlsystems.
The distinction between the fields has become less sharp withtechnical progress. For example, in the high-voltage transmission ofelectric power, large arrays of electronic devices are used to convert
transmission-line current at power levels in the tens of megawatts.Moreover, in the regulation and control of interconnected powersystems, electronic computers are used to compute requirementsmuch more rapidly and accurately than is possible by manualmethods.
The functions performed by electrical and electronics engineersinclude (1) basic research in physics, other sciences, and appliedmathematicsin order to extend knowledge applicable to the field ofelectronics, (2) applied research based on the findings of basicresearch and directed at discovering new applications and principles
of operation, (3) development of new materials, devices, assemblies,and systems suitable for existing or proposed product lines, (4) designof devices, equipment, and systems for manufacture, (5) field-testingof equipment and systems, (6) establishment of quality controlstandards to be observed in manufacture, (7) supervision ofmanufacture and production testing, (8) postproduction assessment ofperformance, maintenance, and repair, and (9) engineeringmanagement, or the direction of research, development,
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The rapid proliferation of new discoveries, products, and markets in
the electrical and electronics industries has made it difficult forworkers in the field to maintain the range of skills required to managetheir activities. Consulting engineers, specializing in new fields, areemployed to study and recommend courses of action.
The educational background required for these functions tends to behighest in basic and applied research. In most major laboratories adoctorate in science or engineering is required to fill leadership roles.Most positions in design, product development, and supervision ofmanufacture and quality control require a masters degree. In thehigh-technology industries typical of modern electronics, an
engineering background at not less than the bachelors level isrequired to assess competitive factors in sales engineering to guidemarketing strategy.
ENVIRONMENTAL ENGINEERING
Environmental engineering consists on the development of processesand infrastructure for the supply of water, the disposal of waste, andthe control ofpollution of all kinds. These endeavours protect publichealth by preventing disease transmission, and they preserve thequality of the environment byaverting the contamination anddegradation of air, water, and landresources.
Environmental engineering is a fieldof broad scope that draws on suchdisciplines as chemistry, ecology,
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geology, hydraulics, hydrology, microbiology, economics, andmathematics. It was traditionally a specialized field within civil
engineering and was called sanitary engineering until the mid-1960s, when the more accurate name environmental engineering wasadopted.
Projects in environmental engineering involve the treatment anddistribution of drinking water (see water supply system); thecollection, treatment, and disposal of wastewater (see wastewater
treatment); the control of air pollution and noise pollution;municipal solid-waste management and hazardous-wastemanagement; the cleanup of hazardous-waste sites; and thepreparation of environmental assessments, audits, and impactstudies. Mathematical modeling and computer analysis are widelyused to evaluate and design the systems required for such tasks.
Chemical and mechanical engineers may also be involved in theprocess. Environmental engineering functions include appliedresearch and teaching; project planning and management; thedesign, construction, and operation of facilities; the sale and
marketing of environmental-control equipment; and the enforcementof environmental standards and regulations.
The education of environmental engineers usually involves graduate-level course work, though some colleges and universities allowundergraduates to specialize or take elective courses in theenvironmental field. Programs offering associate (two-year) degreesare available for training environmental technicians. In the publicsector, environmental engineers are employed by national andregional environmental agencies, local health departments, andmunicipal engineering and public works departments. In the private
sector, they are employed by consulting engineering firms,construction contractors, water and sewerage utility companies, andmanufacturing industries.
INDUSTRIAL ENGINEERING
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It is the application of engineering principles and techniques ofscientific management to the maintenance of a high level of
productivity at optimum cost in industrial enterprises.
The managers responsible for industrial production require anenormous amount of assistance and support because of thecomplexity of most production systems, and the additional burdenof planning, scheduling, and coordination. Historically, this supportwas provided by industrial engineers whose major concern was withmethods, standards, and the organization of process technology.
Industrial engineering originated with the studies of Taylor, the
Gilbreths, and other pioneers of mass production methods. Theirwork expanded into responsibilities that now include the developmentof work methods to increase efficiency and eliminate worker fatigue;the redesign and standardization of manufacturing processes andmethods for handling and transporting materials; the development ofproduction planning and control procedures; and the determinationand maintenance of output standards for workers and machines.Today the field is characterized by an emphasis on mathematical andcomputer modeling.
MECHANICAL ENGINEERING
It is the branch of engineering concerned with the design,manufacture, installation, and operation of engines and machines andwith manufacturing processes. It is particularly concerned with forcesand motion.
Four functions of the mechanical engineer, common to all branches ofmechanical engineering, can be cited. The first is the understanding of
and dealing with the bases of mechanical science. These includedynamics, concerning the relation between forces and motion, such asin vibration; automatic control; thermodynamics, dealing with therelations among the various forms of heat, energy, and power; fluidflow; heat transfer; lubrication; and properties of materials.
Second is the sequence of research, design, and development. Thisfunction attempts to bring about the changes necessary to meet
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present and future needs. Such work requires a clear understanding ofmechanical science, an ability to analyze a complex system into its
basic factors, and the originality to synthesize and invent.
Third is production of products and power, which embraces planning,operation, and maintenance. The goal is to produce the maximumvalue with the minimum investment and cost while maintaining orenhancing longer term viability and reputation of the enterprise or theinstitution.Fourth is the coordinating function of the mechanical engineer,including management, consulting, and, in some cases, marketing.
In these functions there is a long continuing trend toward the use ofscientific instead of traditional or intuitive methods. Operations
research, value engineering, and PABLA (problem analysis by logicalapproach) are typical titles of such rationalized approaches. Creativity,however, cannot be rationalized. The ability to take the important andunexpected step that opens up new solutions remains in mechanicalengineering, as elsewhere, largely a personal and spontaneouscharacteristic.
MATHEMATICS
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It is the science of structure, order, and relation that has evolved from
elemental practices of counting, measuring, and describing theshapes of objects. It deals with logical reasoning and quantitativecalculation, and its development has involved an increasing degree ofidealization and abstraction of its subject matter. Since the 17thcentury, mathematics has been an indispensable adjunct to thephysical sciences and technology, and in more recent times it hasassumed a similar role in the quantitative aspects of the life sciences.The substantive branches of mathematics are: algebra; analysis;arithmetic; combinatorics; game theory; geometry; numbertheory; numerical analysis; optimization; probability theory;set theory; statistics; trigonometry.
PHYSICS
It is the science that deals with the structure of matter and theinteractions between the fundamental constituents of the observableuniverse. In the broadest sense, physics (from the Greek physikos) isconcerned with all aspects of nature on both the macroscopic andsubmicroscopic levels. Its scope of study encompasses not only thebehaviour of objects under the action of given forces but also thenature and origin of gravitational, electromagnetic, and nuclearforce fields. Its ultimate objective is the formulation of a fewcomprehensive principles that bring together and explain all such
disparate phenomena.
Physics is the basic physical science. Until rather recent timesphysics and natural philosophywere used interchangeably for thescience whose aim is the discovery and formulation of thefundamental laws of nature. As the modern sciences developed andbecame increasingly specialized, physics came to denote that part ofphysical science not included in astronomy, chemistry, geology,and engineering. Physics plays an important role in all the naturalsciences, however, and all such fields have branches in which physicallaws and measurements receive special emphasis, bearing such
names as astrophysics, geophysics, biophysics, and evenpsychophysics. Physics can, at base, be defined as the science ofmatter, motion, and energy. Its laws are typically expressed witheconomy and precision in the language ofmathematics.
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MEASUREMENT SYSTEMS
Any of the systems used in the process of associating numbers withphysical quantities and phenomena. Although the concept of weightsand measures today includes such factors as temperature, luminosity,pressure, and electric current, it once consisted of only four basicmeasurements: mass (weight), distance or length, area, and volume(liquid or grain measure). The last three are, of course, closely related.
Basic to the whole idea of weights and measures are the concepts ofuniformity, units, and standards. Uniformity, the essence of anysystem of weights and measures, requires accurate, reliable standardsof mass and length.
UK AND US SYSTEMS
Measurement units that were historically used in the BritishCommonwealth countries. They were very similar, but not identical,
to the units that are still predominantly used in the United States.
The Commonwealth countries have since switched to the SI system ofunits. Because references to the units of the old British customaryimperial units are still found, the following discussion describes thedifferences between the U.S. and British customary systems.
Differences between the U.S. and British Customary Systems
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Measures of length
After 1959, the U.S. and the British inch were defined identically forscientific work and were identical in commercial usage (however, theU.S. retained the slightly different survey inch for specializedsurveying purposes).
Measures of volume
The U.S. customary bushel and the U.S. gallon, and their subdivisionsdiffer from the corresponding British Imperial units.
Also, the British ton is 2240 pounds, whereas the ton generally used inthe United States is the short ton of 2000 pounds.
The American colonists adopted the English wine gallon of 231 cubicinches. The English of that period used this wine gallon and they alsohad another gallon, the ale gallon of 282 cubic inches. In 1824, theBritish abandoned these two gallons when they adopted the BritishImperial gallon, which they defined as the volume of 10 pounds ofwater, at a temperature of 62F, which, by calculation, is equivalent to277.42 cubic inches. At the same time, they redefined the bushel as 8gallons.
METRIC SYSTEM
The metric system is a relatively modern system (just over 200 yearsold) which has been developed based on scientific principles to meetthe requirements of science and trade. As discussed above, theImperial and USA systems have evolved without any such constraints,resulting in a complex set of measurements that fit everyday life in asimple agricultural society but which are unsuited to the requirementsof science and modern trade. Consequently, the metric system offers
a number of substantial advantages:
Simplicity. The Metric system has only 7 basic measures, plus asubstantial number of measures using various combinations of thesebase measures. The imperial system (prior to the UK converting tometric) and the USA system have over 300 different measures ofwhich many are ambiguous.
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Ease of calculation. All the units in the metric system are multiplied by10 (to make larger units) or divided by 10 (to make smaller units). For
example a kilometer is 1000 meters (10 * 10 * 10). It's nearestequivalent is a mile which is 5280 feet (8 * 10 * 22 * 3; based on thecalculation that a mile is 8 furlongs, 10 chains to a furlong, 22 yards toa chain, 3 feet to a yard). Although complex calculations can be doneusing the Imperial or USA system, almost all calculations can be doneeasier and faster in the metric system.
International Standard. With the exception of the USA, all majorcountries have converted to the metric system (although in somecountries, such as the UK, the conversion to metric is not yetcomplete). Consequently, for any international communication (trade,
science, etc.) the metric system is the most widely used andaccepted.
Length
Metric Imperial
1 millimetre [mm]0.03937
in
1 centimetre
[cm]
10
mm 0.3937 in
1 metre [m]100
cm
1.0936
yd
1 kilometre
[km]
1000
m
0.6214
mile
Imperial Metric
1 inch [in] 2.54 cm
1 foot [ft] 12 in0.3048
m
1 yard [yd] 3 ft0.9144
m
1 mile 1760 yd1.6093
km
1 int nautical 2025.4 1.853
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mile yd km
Area
Metric Imperial
1 sq cm
[cm2]100 mm2 0.1550 in2
1 sq m[m2]
10,000cm2
1.1960yd2
1 hectare
[ha]
10,000
m2
2.4711
acres
1 sq km
[km2]100 ha
0.3861
mile2
Imperial Metric
1 sq inch [in2]6.4516
cm2
1 sq foot[ft2]
144 in20.0929m2
1 sq yd [yd2] 9 ft20.8361
m2
1 acre4840
yd2
4046.9
m2
1 sq mile
[mile2]
640
acres 2.59 km2
Volume
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MetricImperi
al
1 cu cm [cm3]0.0610
in3
1 cu
decimetre
[dm3]
1,000
cm3
0.0353
ft3
1 cu metre
[m3]
1,000
dm3
1.3080
yd3
1 litre [l]1
dm31.76 pt
1
hectolitre
[hl]
100 l21.997
gal
Imperial Metric
1 cu inch
[in3]
16.387
cm3
1 cu
foot
[ft3]
1,728
in3
0.0283
m3
1 fluid ounce[fl oz]
28.413ml
1 pint
[pt]
20 fl
oz
0.5683
l
Mass
Metric Imperial
1 milligram [mg]0.0154
grain
1 gram [g]1,000
mg0.0353 oz
1 kilogram
[kg]1,000 g 2.2046 lb
1 tonne [t]1,000
kg
0.9842
ton
Imperial Metric
1 ounce [oz]437.5
grain28.35 g
1 pound [lb] 16 oz0.4536
kg
1 stone 14 lb6.3503
kg
1 hundredweight
[cwt]112 lb
50.802
kg
USA measureMetri
c
1 fluid
ounce
1.0408
uk fl oz
29.57
4 ml
1 pint
(16 fl
oz)
0.8327
uk pt
0.473
1 l
1
gallon
0.8327
uk gal
3.785
4 l
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1 long ton (uk) 20 cwt 1.016 t
MEASUREMENT INSTRUMENTATION
For time
Clock:A clock is an instrument used to indicate, measure, keep, and
co-ordinate time. The modern clock has been used since the 14thCentury.
Chronometer:A chronometer is a very accurate time-keeping devicethat is used for determining precise duration of events.
www.enchantedlearning.com/explorers/glossary.shtml
Calendar: A calendar is a system of organizing days for social,religious, commercial, or administrative purposes. This is done bygiving names to periods of time, typically days, weeks, months, and
years. The name given to each day is known as a date.
wordnetweb.princeton.edu/perl/webwn
Atomic Clock: a timepiece that derives its time scale from thevibration of atoms or molecules.
wordnetweb.princeton.edu/perl/webwn
For Length
Tape Measure: measuring instrument consisting of a narrow strip(cloth or metal) marked in inches or centimeters and used formeasuring lengths.
wordnetweb.princeton.edu/perl/webwn
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Odometer: Instrument used to record journeys or total mileage of acar.
www.mechanicsregister.com/glossary.php
Altimeter: an instrument that measures the height above ground;used in navigation
Vernier Scale: A small movable scale that slides along a main scale;the small scale is calibrated to indicate fractional divisions of the mainscale
Caliper: an instrument for measuring the distance between two
points (often used in the plural)
.
Opisometer: An opisometer, also called a meilograph or map
measurer, is an instrument for measuring the lengths of arbitrarycurved lines.
For Volume
Measuring cup: Graduated cup used to measure liquid or granularingredients.
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Pipet: Measuring instrument consisting of a graduated glass tubeused to measure or transfer precise volumes of a liquid by drawing the
liquid up.
Beaker: A beaker is a simple container for stirring, mixing andheating liquids commonly used in many laboratories. Beakers aregenerally cylindrical in shape, with a flat bottom and a lip for pouring.
Eudiometer: Measuring instrument consisting of a graduated glasstube for measuring volume changes in chemical reactions betweengases.
For Speed:
Radar gun: Measuring instrument consisting of a graduated glasstube for measuring volume changes in chemical reactions betweengases.
Speedometer: An instrument that records the speed of a vehicle inmotion for the driver of the vehicle.
Tachometer:Used to measure the speed of rotation of a gear or
shaft or other rotating part of the engine.
www.mechanicsregister.com/glossary.php
For mass:
Balance: A devise based on gravity and equilibrium among two sides,one side used for the measuring sample and the other for thecomparing standard.
Weighing Scales: is a measuring instrument for determining theweight or mass of an object
Mass spectrometer: is an instrument that can measure the massesand relative concentrations of atoms and molecules. It makes use ofthe basic magnetic force on a moving charged particle. Massspectrometers are sensitive detectors of isotopes based on theirmasses
http://www.google.com/url?ei=mcK_S5SYOoO78gbf_cnGCA&sig2=UIauwpmr7OVE-okanzU-Lg&q=http://www.mechanicsregister.com/glossary.php&ei=mcK_S5SYOoO78gbf_cnGCA&sa=X&oi=define&ct=&cd=1&ved=0CBAQpAMoBQ&usg=AFQjCNH3L4pfoVDNxgE3kWsOTf-NpY9LBQhttp://en.wikipedia.org/wiki/Measuring_instrumenthttp://en.wikipedia.org/wiki/Weighthttp://en.wikipedia.org/wiki/Masshttp://www.google.com/url?ei=mcK_S5SYOoO78gbf_cnGCA&sig2=UIauwpmr7OVE-okanzU-Lg&q=http://www.mechanicsregister.com/glossary.php&ei=mcK_S5SYOoO78gbf_cnGCA&sa=X&oi=define&ct=&cd=1&ved=0CBAQpAMoBQ&usg=AFQjCNH3L4pfoVDNxgE3kWsOTf-NpY9LBQhttp://en.wikipedia.org/wiki/Measuring_instrumenthttp://en.wikipedia.org/wiki/Weighthttp://en.wikipedia.org/wiki/Mass8/23/2019 libro tl1
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For Pressure:
Anemometer: A gauge for recording the speed and direction of wind.
Barometer: An instrument that measures atmospheric pressure.
Manometer: Device to measure pressures. A common simplemanometer consists of a U shaped tube of glass filled with someliquid. Typically the liquid is mercury because of its high density.
Tire Pressure Gauge: A tire-pressure gauge is a pressure gauge
used to measure the pressure of tires on a vehicle.
For Electricity:
Ohmmeter: A meter for measuring electrical resistance in ohms,
Ammeter: A meter that measures the flow of electrical current inamperes.
Voltimeter: meter that measures the potential difference betweentwo points in volts.
Multimeter: A multimeter or a multitester, also known as a volt/ohmmeter or VOM, is an electronicmeasuring instrument that combinesseveral measurement functions in one unit. A typical multimeter mayinclude features such as the ability to measure voltage, current and
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resistance. There are two categories of multimeters, analogmultimeters and digital multimeters (often abbreviated DMM or
DVOM.)
For Angles:
Protractor:A semi-circle device used for measuring angles. The edge is subdividedinto degrees.
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SCIENCE AND TECHNOLOGY
DEFINITION
When you hear the term science, it is typically associated with theterm technology. Although these two terms are often interchanged,there is actually a sparse difference between the two.
Perhaps the best way to differentiate science from technology is tohave a quick definition of each term. Science is a system of acquiringknowledge based on the scientific method, as well as the organizedbody of knowledge gained through such research, in order to reliablypredict the type of outcome. It can be broadly defined as the study ofthings with branches like biology, chemistry, physics and psychology.
Technology, on the other hand, is more of an applied science. Its abroad concept that deals with a species' usage and knowledge of toolsand crafts to control and adapt them to its environment, and also tobe used for the study of a particular science. For example, the scienceof energy can have technology as its application. In the case of energyas a subject in science, solar panels can be used for a variety oftechnologies, an example of which are solar-powered lights.
If the goal of science is the pursuit of knowledge for sciences sake,technology aims to create systems to meet the needs of people.Science has a quest of explaining something, while technology isleaning more towards developing a use for something.
Science focuses more on analysis, generalizations and the creation oftheories, while technology focuses more on analysis and synthesis ofdesign. Science is controlled by experimentation, while technologyalso involves design, invention and production. If science is all abouttheories, technology is all about processes. Finally, in order to excel inscience, its needed to have experimental and logical skills.
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Meanwhile, technology requires a myriad of skills including design,construction, testing, quality assurance and problem-solving.
DIFFERENCES BETWEEN SCIENCE AND TECHNOLOGY
Kingsley Davis (1908 1997), identified by the American PhilosophicalSociety as one of the most outstanding social scientists of thetwentieth century, tried to distinguish between science andtechnology. According to him, science is the part of the culturalheritage which represents a systematic knowledge of nature, whiletechnology contains the application of this knowledge.
Other distinction between these two terms is that the ends oftechnology are empirical, which can be practically demonstrated.These ends are purely instrumental, which isnt the case with thescience.
Another difference, pointed out by Kingsley Davis, is that technologyencounters less conflict with morality in one sense because it isalways aimed in achieving a utilitarian goal. Without the goal, the
technology would be meaningless. Therefore, the usefulness oftechnology is always apparent, whereas the usefulness for the searchof truth is not so apparent.
Summarizing all of the above, the differentiation between science andtechnology can be characterized by three key factors:
1. The domains core business (its purpose)
2. Its view of what exists in the world (its ontological stance)3. How it defines and validates knowledge (its epistemology)
To have a better idea of these key factors, lets check the followingchart:
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SCIENCE TECHNOLOGY
Most
observed
quality:
Drawing correct
conclusions based on
good theories and
accurate data
Taking good decisions
based on incomplete data
and approximate models
Skills
needed to
excel:
Experimental and
logical skills needed
Design, construction,
testing, planning, qualityassurance, problem
solving, decision making,
interpersonal and
communication skills
Mission:The search for and
theorizing about cause
The search for and
theorizing about new
processes
Motto:
Reductionism,
involving the isolation
and definition of
distinct concepts
Holism, involving the
integration of many
competing demands,
theories, data and ideas
Result
Relevance:
Making virtually value-
free statements
Activities always value-
laden
Goal:
Pursuit of knowledge
and understanding for
its own sake (New
knowledge)
The creation of artifacts
and systems to meet
people's needs (New
products)
Goals
achieved
through:
Corresponding
Scientific Processes
Key Technological
Processes
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Developmen
t Methods:
Discovery (controlled
by experimentation)
Design, invention,
production
Evaluation
Methods:
Analysis,
generalization and
creation of theories
Analysis and synthesis of
design
HOW DO SCIENCE AND TECHNOLOGY RELATE?
Scientific knowledge and methodologies themselves provide a majorsource of input into the development of technological practices andoutcomes. They are also key tools in the establishment of
explanations of why technological interventions were, or were not,successful. In short, science can provide powerful explanations for thewhy and why not behind technological intervention. However, as theseinterventions rely on more than an understanding of the natural world,they can only provide partial justification for technological practicesand outcomes.
Technological practices, knowledge and outcomes can provide
mechanisms for science to gain a better view of its defined world, and
in fact can provide serious challenges to the defining of that world. Forexample, the development of the technological artefacts that extend
the observation capabilities of humans (such as the telescope and
microscope), made visible and available new worlds for science to
interrogate and explain.
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CHEMISTRY
Chemistry is the science of the materials that make up our physicalworld (physical science). Chemistry tends to focus on the properties ofsubstances and the interactions between different types of matter,
particularly reactions that involve electrons. Physics tends to focusmore on the nuclear part of the atom, as well as the subatomic realm.No person could expect to master all aspects of such a vast field, so ithas been found convenient to divide the subject into smaller areas.
For example:
Organic chemists study compounds of carbon. Atoms of thiselement can form stable chains and rings, giving rise to verylarge numbers of natural and synthetic compounds.
Biochemists concern themselves with the chemistry of the
living world.
Inorganic chemists are interested in all elements, butparticularly in metals, and are often involved in the preparationof new catalysts.
Physical chemists study the structures of materials, and ratesand energies of chemical reactions.
Theoretical chemists with the use of mathematics andcomputational techniques derive unifying concepts to explainchemical behavior.
Analytical chemists develop test procedures to determine theidentity, composition and purity of chemicals and materials.New analytical procedures often discover the presence ofpreviously unknown compounds.
One of the main functions of the chemist is to rearrange the atoms ofknown substances to produce new products. For example, chemists
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have developed previously unknown synthetic fibers such as Kevlar,which has desirable qualities not found in natural fibers. The
development of plastics such as polyethylene and Teflon has resultedin the production of many new items previously unavailable becauseno natural product could do the job. New alloys and special fuels allowus to travel in outer space. Chemists have helped to develop theseand thousands of other new and useful products.
Atomic and Molecular Structure
All matter consists of particles called atoms. Atoms are single units ofan element. Ions can be made up of one or more types of elementsand carry an electrical charge. Learn about the parts of an atom andhow to identify the different types of ions.
Atoms cannot be divided using chemicals. They do consist of parts,which include protons, neutrons, and electrons, but an atom is a basicchemical building block of matter.
Each electron has a negative electrical charge.
Each proton has a positive electrical charge. The charge of a
proton and an electron are equal in magnitude, yet opposite insign. Electrons and protons are electrically attracted to eachother.
Each neutron is electrically neutral. In other words, neutrons donot have a charge and are not electrically attracted to eitherelectrons or protons.
Protons and neutrons are about the same size as each other andare much larger than electrons. The mass of a proton isessentially the same as that of a neutron. The mass of a proton
is 1840 times greater than the mass of an electron.
The nucleus of an atom contains protons and neutrons. Thenucleus carries a positive electrical charge.
Electrons move around outside the nucleus.
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Almost all of the mass of an atom is in its nucleus; almost all ofthe volume of an atom is occupied by electrons.
The number of protons (also known as its atomic number)determines the element. Varying the number of neutrons resultsin isotopes. Varying the number of electrons results in ions.Isotopes and ions of an atom with a constant number of protonsare all variations of a single element.
The particles within an atom are bound together by powerfulforces. In general, electrons are easier to add or remove from anatom than a proton or neutron. Chemical reactions largelyinvolve atoms or groups of atoms and the interactions between
their electrons.
Atomic numbers and Atomic Mass
Since atomic number is the number of protons in an atom and atomicmass is the mass of protons, neutrons, and electrons in an atom, itseems intuitively obvious that increasing the number of protons wouldincrease the atomic mass, but the reality is different: Atomic number
doesnt always equate to increasing mass because many atoms don'thave a number of neutrons equal to the number of protons. In otherwords, several isotopes of an element may exist (elements with thesame atomic number but with different atomic mass). If a sizeableportion of an element of lower atomic number exists in the form ofheavy isotopes, then the mass of that element may (overall) beheavier than that of the next element. If there were no isotopes andall elements had a number of neutrons equal to the number ofprotons, then atomic mass would be approximately twice the atomicnumber (approximately because protons and neutrons don't haveexactly the same mass... the mass of electrons is so small that it is
negligible).
Molecule
Molecules are small particles that make up all living and non-livingthings. Every molecule is unique due to its chemical properties. Theyare made up of even tinier particles called atoms. Molecules in living
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things are made from only about 25 of more than 100 known atoms inthe universe. Molecules are made from as few as two atoms to
hundreds of millions of atoms. Molecules main characteristic is itsgeometry or structure, which is unique to every molecule.
The Mole
A mole is defined as the quantity of a substance that has the samenumber of particles as are found in 12.000 grams of carbon-12. Thisnumber, Avogadro's number, is 6.022x1023. The mass in grams of onemole of a compound is equal to the molecular weight of the compoundin atomic mass units. One mole of a compound contains 6.022x10 23
molecules of the compound. The mass of 1 mole of a compound is
called its molar weightor molar mass. The units for molar weight ormolar mass are grams per mole. Here is the formula for determiningthe number of moles of a sample:
mol = weight of sample (g) / molar weight (g/mol)
Chemical bond
It is a region that forms when electrons from different atoms interactwith each other. The electrons that participate in chemical bonds arethe valence electrons, which are the electrons found in an atom's
outermost shell. When two atoms approach each other these outerelectrons interact. Electrons repel each other, yet they are attractedto the protons within atoms. The interplay of forces results in someatoms forming bonds with each other and sticking together.
The two main types of bonds formed between atoms are ionic bondsand covalent bonds. An ionic bond is formed when one atom acceptsor donates one or more of its valence electrons to another atom. Acovalent bond is formed when atoms share valence electrons. Theatoms do not always share the electrons equally, so a polar covalentbond may be the result. When electrons are shared by two metallic
atoms a metallic bond may be formed. In a covalent bond, electronsare shared between two atoms. The electrons that participate inmetallic bonds may be shared between any of the metal atoms in theregion.
If the electronegativity values of two atoms are:
Similar...
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o Metallic bonds form between two metal atoms.
o Covalent bonds form between two non-metal atoms.
o Nonpolar covalent bonds form when the electronegativityvalues are very similar.
o Polar covalent bonds form when the electronegativityvalues are a little further apart.
Different...
o Ionic bonds are formed.
Chemical Reaction
A chemical reaction is a process that is usually characterized by achemical change in which the starting materials (reactants) aredifferent from the products. Chemical reactions tend to involve themotion ofelectrons, leading to the formation and breaking ofchemicalbonds. There are several different types of chemical reactions andmore than one way of classifying them. Here are some commonreaction types:
Direct Combination or Synthesis ReactionIn a synthesis reaction two or more chemical species combine toform a more complex product.
A + B --> AB
The combination of iron and sulfur to form iron (II) sulfide is anexample of a synthesis reaction:
8 Fe + S8 --> 8 FeS
Chemical Decomposition or Analysis ReactionIn a decomposition reaction a compound is broken into smallerchemical species.
AB --> A + B
The electrolysis of water into oxygen and hydrogen gas is anexample of a decomposition reaction:
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2 H2O --> 2 H2 + O2
Single Displacement or Substitution ReactionA substitution or single displacement reaction is characterizedby one element being displaced from a compound by anotherelement.
A + BC --> AC + B
An example of a substitution reaction occurs when zinccombines with hydrochloric acid. The zinc replaces thehydrogen:
Zn + 2 HCl --> ZnCl2 + H2
Metathesis or Double Displacement ReactionIn a double displacement or metathesis reaction two compoundsexchange bonds or ions in order to form different compounds.
AB + CD --> AD + CB
An example of a double displacement reaction occurs betweensodium chloride and silver nitrate to form sodium nitrate and
silver chloride.
NaCl(aq) + AgNO3(aq) --> NaNO3(aq) + AgCl(s)
Acid-Base ReactionAn acid-base reaction is type of double displacement reactionthat occurs between an acid and a base. The H+ ion in the acidreacts with the OH- ion in the base to form water and an ionicsalt:
HA + BOH --> H2O + BA
The reaction between hydrobromic acid (HBr) and sodiumhydroxide is an example of an acid-base reaction:
HBr + NaOH --> NaBr + H2O
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Oxidation-Reduction or Redox ReactionIn a redox reaction the oxidation numbers of atoms are
changed. Redox reactions may involve the transfer of electronsbetween chemical species.
The reaction that occurs when In which I2 is reduced to I- andS2O32- (thiosulfate anion) is oxidized to S4O62- provides anexample of a redox reaction:
2 S2O32(aq) + I2(aq) --> S4O62(aq) + 2 I(aq)
CombustionA combustion reaction is a type of redox reaction in which a
combustible material combines with an oxidizer to form oxidizedproducts and generate heat (exothermic reaction). Usually incombustion reactions oxygen combines with another compoundto form carbon dioxide and water. An example of a combustionreaction is the burning of naphthalene:
C10H8 + 12 O2 ---> 10 CO2 + 4 H2O Isomerization
In an isomerization reaction, the structural arrangement of acompound is changed but its net atomic composition remainsthe same.
Hydrolysis Reaction
A hydrolysis reaction involves water. The general form for ahydrolysis reaction is:
X-(aq) + H2O(l) HX(aq) + OH-(aq)
Why Study Chemistry?
Understanding chemistry helps you to understand the world around
you. Cooking is chemistry. Everything you can touch or taste or smellis a chemical. When you study chemistry, you come to understand abit about how things work. Chemistry isn't secret knowledge, uselessto anyone but a scientist. It's the explanation for everyday things, likewhy laundry detergent works better in hot water or how baking sodaworks or why not all pain relievers work equally well on a headache. Ifyou know some chemistry, you can make educated choices abouteveryday products that you use.
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Chemistry is involved with everything with which we come in contact.The life processes of all organisms involve chemical changes.
Chemists play a key role in the development of drugs, which arehelping to cure and alleviate diseases and prolong life span. Chemistsare involved in biochemistry and genetic engineering.
For example, there is much interest in producing new bacterialstrains, which can synthesize useful products such as human insulin orinterferon. Chemists are also at the forefront of developing fields suchas nanotechnology. They are actively involved in environmental issuesand are helping to tap new sources of energy to replace the earth'sfinite reserves of petroleum.
Our high standard of living depends heavily on the contributions ofchemists to agriculture, manufacturing, new technologies, and thedevelopment of efficient means of transportation and communication.Thus, with its broad scope, chemistry offers an exciting array ofintellectual adventures and opportunities.
What Fields of Study Use Chemistry?
You could use chemistry in most fields, but it's commonly seen in thesciences and in medicine. Chemists, physicists, biologists, andengineers study chemistry. Doctors, nurses, dentists, pharmacists,
physical therapists, and veterinarians all take chemistry courses.Science teachers study chemistry. Fire fighters and people who makefireworks learn about chemistry. So do truck drivers, plumbers, artists,hairdressers, chefs... the list is extensive.
The career options in chemistry are practically endless!
Chemistry is a part of biology and physics, plus, there are lots ofcategories of chemistry! Here's look at some of the career optionsrelated to chemistry:
Chemistry Engineering EnvironmentalLaw
Pharmaceuticals
Patent Law TechnicalWriting
Space Exploration Biotechnology
Oceanography
SoftwareDesign
GovernmentPolicy
CeramicsIndustry
Metallurgy Plastics Forensic Paper Industry
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Medicine
Industry
Teaching
Science
Ethnobotany Geochemistry
Agrochemistry MilitarySystems
STATISTICSStatistics can be defined as the practice of collecting, organizing,describing, and analyzing data to draw conclusions from the data toapply to a cause. Data must either be numeric in origin or transformedby researchers into numbers.
There are two main branches of statistics: descriptive and inferential.Descriptive statistics is used to say something about a set ofinformation that has been collected only. Inferential statistics is usedto make predictions or comparisons about a larger group (a
population) using information gathered about a small part of thatpopulation. Thus, inferential statistics involves generalizing beyondthe data, something that descriptive statistics does not do.
According to the order, first, descriptive statistics will be explained inthis textbook. It is recommended to read and study the main conceptsrelated with statistics, which are defined along with this topic in thistextbook.
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Descriptive Statistics
Descriptive statistics describe patterns and general trends in a dataset. In most cases, descriptive statistics are used to examine orexplore one variable at a time. However, the relationship between twovariables can also be described as with correlation and regression.
The first phase of data analysis involves the placing of some order onsome sort of chaos. Typically the data are reduced down to one ortwo descriptive summaries like the mean and standard deviation orcorrelation, or by visualization of the data through various graphicalprocedures like histograms, frequency distributions, and scatter plots.
Frequency Distributions
These types of distributions are a way of displaying chaos of numbersin an organized manner so such questions can be answered easily. Afrequency distribution is simply a table that, at minimum, displayshow many times in a data set each response or "score" occurs. A goodfrequency distribution will display more information than this althoughwith just this minimum information, many other bits of informationcan be computed.Measures of Central Tendency
This type of measurements gives a single description of the averageor "typical" score in a data distribution. These measures attempt toquantify what we mean when we think of as the "average" score in adata set. The concept is extremely important and we encounter itfrequently in daily life. For example, we often want to know beforepurchasing a car its average distance per liter of petrol. Or beforeaccepting a job, you might want to know what a typical salary is forpeople in that position so you will know whether or not you are goingto be paid what you are worth.
In the mathematical world, where everything must be precise, we
define several ways of finding the center of a set of data, such as:
1. Median: the median is the middle number of a set of numbersarranged in numerical order. If the number of values in a set is even,then the median is the sum of the two middle values, divided by 2.
The median is not affected by the magnitude of the extreme (smallestor largest) values. Thus, it is useful because it is not affected by one or
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two abnormally small or large values, and because it is very simple tocalculate. (For example, to obtain a relatively accurate average life of
a particular type of lightbulb, you could measure the median life byinstalling several bulbs and measuring how much time passed beforehalf of them died. Alternatives would probably involve measuring thelife of each bulb.)
2. Mode: the mode is the most frequent value in a set. A set can havemore than one mode; if it has two, it is said to be bimodal. The modeis useful when the members of a set are very different, for examplethe comparison of grades of a test (A, B, C, D, E). On the other hand,the fact that the mode is absolute (which means that, for instance2.99 and 3 are considered completely different) can make the mode a
poor choice for determining a center.
3. Mean: the mean is the sum of all the values in a set, divided by thenumber of values. The mean of a whole population is usually denoted
by , while the mean of a sample is usually denoted by .
Measures of Variability
The average score in a distribution is important in many researchcontexts. So too is another set of statistics that quantify how variableor how dispersed the scores in a set of data tend to be. Sometimesvariability in scores is the central issue in a research question.Variability is a quantitative concept, so none of this applies todistributions of qualitative data. The principal measures of variabilityare described in the following subtopics.
1. Range: the range is the difference between the largest and
smallest values of a set. The range of a set is simple to calculate, butis not very useful because it depends on the extreme values, whichmay be distorted.
2. Variance: the variance is a measure of how items are dispersedabout their mean. The variance 2 of a whole population is given bythe equation:
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The variance s2 of a sample is calculated differently:
3. Standard deviation: The standard deviation (or s for asample) is the square root of the variance. (Thus, for a population, thestandard deviation is the square root of the average of the squareddeviations from the mean. For a sample, the standard deviation is the
square root of the sum of the squared deviations from the mean,divided by the number of samples minus 1.)
4. Relative variability:The relative variability of a set is its standarddeviation divided by its mean. The relative variability is useful forcomparing several variances.
Inferential Statistics
Inferential statistics are used to judge the meaning of data. Inferentialstatistics assess how likely it is that group differences or correlationswould exist in the population rather than occurring only due tovariables associated with the chosen sample.
Two basic uses of inferential statistics are possible:
a) Confidence intervals, which is also referred to as Intervalestimation.
b) Hypothesis testing, which is also referred to as Point Estimation.
Confidence Intervals and point estimation are two different ways ofexpressing the same information.
Using Confidence Intervals we make statements like the following:
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The probability that the population mean (, or the 'true' valueof the population mean) lies between 19 and 23 is 0.80;
The probability that the population correlation value (r, or the'true' value of the correlation between these two variables) liesbetween 0.20 and 0.24 is 0.60
Using Hypothesis testing we say:
The probability that our sample mean comes from a populationwith a mean of 21 is greater than 0.95
The probability that our sample comes from a population inwhich the true correlation is zero is 0.60.
The most remarkable topics regarding this type of statistics are dealtas it follows.
The Hypothesis testing
Oftentimes we want to determine whether a claim is true or false.Such a claim is called a hypothesis. It is important to clear up someterms such as:
1. Null hypothesis: a specific hypothesis to be tested in anexperiment. The null hypothesis is usually labeled H0.
2. Alternative hypothesis: a hypothesis that is different from thenull hypothesis, which we usually want to show that is true (therebyshowing that the null hypothesis is false). The alternative hypothesisis usually labeled Ha.
If the alternative involves showing that some value is greater than orless than a number, there is some value c that separates the nullhypothesis rejection region from the fail to reject region. This value isknown as the critical value.
The null hypothesis is tested through the following procedure:
a) Determine the null hypothesis and an alternative hypothesis.
b) Pick an appropriate sample.
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c) Use measurements from the sample to determine the likelihood ofthe null hypothesis.
Other important concepts when studying hypothesis test are:
1. Type 1 Error: If the null hypothesis is true but the sample mean issuch that the null hypothesis is rejected, a Type I error occurs. The
probability that such an error will occur is the risk.
2. Type 2 Error: If the null hypothesis is false but the sample mean issuch that the null hypothesis cannot be rejected, a Type II error
occurs. The probability that such an error will occur is called the risk.
Confidence Intervals
Interval estimation is used when we wish to be fairly certain that thetrue population value is contained within that interval. When weattach a probability statement to an estimated interval, we obtain aconfidence interval.
Confidence is defined as (1 minus the significance level). Thus,
when we construct a 95% confidence interval, we are saying that weare 95% certain that the true population mean is covered by theinterval - consequently, of course, we have a 5% chance of beingwrong. Any statistic that can be evaluated in a test of significance("hypothesis testing") can be used in constructing a confidenceinterval. Always, when constructing a confidence interval, two limits("Upper" and "Lower") are computed. For each limit, the information
needed is the computed statistic (e.g., ), the two-tailed critical
values (e.g., ), and the standard error for the statistic.
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PHYSICS
Physics is the science of natural phenomena, the relationship betweenspace and time, based on their properties.It is divided into several branches:
Kinematics: Examines the consequences of the motion of bodiesin space and time.
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Dynamics: Examines the causes of the motion of bodies inrelation to space and time.
Geometric Optics: studies all the phenomena of light by meansof analytical geometry.
Electromagnetic Optics: studies all the phenomena of light bymeans of their frequencies.
Acoustic: studies all phenomena linked to mechanical waves andelectromagnetic.
Thermodynamics: studies all phenomena related to thetemperature (not just with the heat, as many believe).
Electricity: studies all phenomena related to electricity. This issometimes subdivided into: * static: studies everything relatedto electrical energy stored in objects. * Dynamic: Studieseverything related to the movement of electrons.
Electromagnetism: Studies everything about the causes andeffects of magnetic fields.
Physics and its applications
Many applications of physics illustrate and use concepts from across awide range of topics. Physics applications will eventually containcollections of experiments covering applications such ascommunications, transport and medical imaging.
Ultimately, the goal of physics is not only to understand the workingsof the univ
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