1.
Spirit level
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A spirit level, bubble level or simply a level is an instrument designed to indicate whether a surface is horizontal or vertical. Early spirit levels had very slightly curved glass vials with constant inner diameter at each viewing point and these vials are incompletely filled with a liquid, usually a colored spirit or alcohol, leaving a bubble in the tube. They have an upward curve, so that the bubble naturally rests in the center. At slight inclinations the bubble travels away from the center position. Where a spirit level must also be usable upside-down or on its side, alcohols such as ethanol are often used rather than water. Alcohols have low viscosity and surface tension, which allows the bubble to travel the tube quickly, alcohols also have a much wider liquid temperature range, and wont break the vial as water could due to ice expansion. A colorant such as fluorescein, typically yellow or green, may be added to increase the visibility of the bubble. An extension of the level is the bulls eye level. It serves to level a surface across a plane, while the level only does so in the direction of the tube. To check the accuracy of a carpenters type level, a horizontal surface is not needed. The level is placed on a flat and roughly level surface and this reading indicates to what extent the surface is parallel to the horizontal plane, according to the level, which at this stage is of unknown accuracy. The spirit level is then rotated through 180 degrees in the horizontal plane, if the level is accurate, it will indicate the same orientation with respect to the horizontal plane. A difference implies that the level is inaccurate, a similar procedure is applied to more sophisticated instruments such as a surveyors level or a theodolite and is a matter of course each time the instrument is set up. In this latter case, the plane of rotation of the instrument is levelled and this is done in two horizontal perpendicular directions. The sensitivity is an important specification for a level, its accuracy depends on its sensitivity. The sensitivity of a level is given as the change of angle or gradient required to move the bubble by unit distance, if the bubble housing has graduated divisions then the sensitivity is the angle or gradient change that moves the bubble by one of these divisions. 2 mm is the spacing for graduations, on a surveyors level the bubble will move 2 mm when the vial is tilted about 0.005 degree. For a precision machinist level with 2mm divisions, when the vial is tilted 5 arc seconds the bubble will move one graduation and this is equivalent to movement of.0005 inches measured one foot from the pivot point, referred to as 5 ten-thousandths per foot
2.
Measuring instrument
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A measuring instrument is a device for measuring a physical quantity. In the physical sciences, quality assurance, and engineering, measurement is the activity of obtaining and comparing physical quantities of objects and events. Established standard objects and events are used as units, and the process of measurement gives a number relating the item under study, measuring instruments, and formal test methods which define the instruments use, are the means by which these relations of numbers are obtained. All measuring instruments are subject to varying degrees of instrument error, scientists, engineers and other humans use a vast range of instruments to perform their measurements. These instruments may range from simple objects such as rulers and stopwatches to electron microscopes, virtual instrumentation is widely used in the development of modern measuring instruments. In the past, a common time measuring instrument was the sundial, today, the usual measuring instruments for time are clocks and watches. For highly accurate measurement of time a clock is used. Stop watches are used to measure time in some sports. Energy is measured by an energy meter, examples of energy meters include, An electricity meter measures energy directly in kilowatt hours. A gas meter measures energy indirectly by recording the volume of gas used and this figure can then be converted to a measure of energy by multiplying it by the calorific value of the gas. A physical system that exchanges energy may be described by the amount of energy exchanged per time-interval, for the ranges of power-values see, Orders of magnitude. Action describes energy summed up over the time a process lasts and its dimension is the same as that of an angular momentum. A phototube provides a measurement which permits the calculation of the quantized action of light. This includes basic quantities found in classical- and continuum mechanics, dumpy level Laser line level Spirit level Gyroscope Ballistic pendulum, indirectly by calculation and or gauging Considerations related to electric charge dominate electricity and electronics. Electrical charges interact via a field and that field is called electric if the charge doesnt move. If the charge moves, thus realizing an electric current, especially in a neutral conductor. Electricity can be given a quality — a potential, and electricity has a substance-like property, the electric charge. Energy in elementary electrodynamics is calculated by multiplying the potential by the amount of charge found at that potential, potential times charge, electrometer is often used to reconfirm the phenomenon of contact electricity leading to triboelectric sequences
3.
Ancient Egypt
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Ancient Egypt was a civilization of ancient Northeastern Africa, concentrated along the lower reaches of the Nile River in what is now the modern country of Egypt. It is one of six civilizations to arise independently, Egyptian civilization followed prehistoric Egypt and coalesced around 3150 BC with the political unification of Upper and Lower Egypt under the first pharaoh Narmer. In the aftermath of Alexander the Greats death, one of his generals, Ptolemy Soter and this Greek Ptolemaic Kingdom ruled Egypt until 30 BC, when, under Cleopatra, it fell to the Roman Empire and became a Roman province. The success of ancient Egyptian civilization came partly from its ability to adapt to the conditions of the Nile River valley for agriculture, the predictable flooding and controlled irrigation of the fertile valley produced surplus crops, which supported a more dense population, and social development and culture. Its art and architecture were widely copied, and its antiquities carried off to far corners of the world and its monumental ruins have inspired the imaginations of travelers and writers for centuries. The Nile has been the lifeline of its region for much of human history, nomadic modern human hunter-gatherers began living in the Nile valley through the end of the Middle Pleistocene some 120,000 years ago. By the late Paleolithic period, the climate of Northern Africa became increasingly hot and dry. In Predynastic and Early Dynastic times, the Egyptian climate was less arid than it is today. Large regions of Egypt were covered in treed savanna and traversed by herds of grazing ungulates, foliage and fauna were far more prolific in all environs and the Nile region supported large populations of waterfowl. Hunting would have been common for Egyptians, and this is also the period when many animals were first domesticated. The largest of these cultures in upper Egypt was the Badari, which probably originated in the Western Desert, it was known for its high quality ceramics, stone tools. The Badari was followed by the Amratian and Gerzeh cultures, which brought a number of technological improvements, as early as the Naqada I Period, predynastic Egyptians imported obsidian from Ethiopia, used to shape blades and other objects from flakes. In Naqada II times, early evidence exists of contact with the Near East, particularly Canaan, establishing a power center at Hierakonpolis, and later at Abydos, Naqada III leaders expanded their control of Egypt northwards along the Nile. They also traded with Nubia to the south, the oases of the desert to the west. Royal Nubian burials at Qustul produced artifacts bearing the oldest-known examples of Egyptian dynastic symbols, such as the crown of Egypt. They also developed a ceramic glaze known as faience, which was used well into the Roman Period to decorate cups, amulets, and figurines. During the last predynastic phase, the Naqada culture began using written symbols that eventually were developed into a system of hieroglyphs for writing the ancient Egyptian language. The Early Dynastic Period was approximately contemporary to the early Sumerian-Akkadian civilisation of Mesopotamia, the third-century BC Egyptian priest Manetho grouped the long line of pharaohs from Menes to his own time into 30 dynasties, a system still used today
4.
Surveying
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Surveying or land surveying is the technique, profession, and science of determining the terrestrial or three-dimensional position of points and the distances and angles between them. A land surveying professional is called a land surveyor, Surveyors work with elements of geometry, trigonometry, regression analysis, physics, engineering, metrology, programming languages and the law. Surveying has been an element in the development of the environment since the beginning of recorded history. The planning and execution of most forms of construction require it and it is also used in transport, communications, mapping, and the definition of legal boundaries for land ownership. It is an important tool for research in other scientific disciplines. Basic surveyance has occurred since humans built the first large structures, the prehistoric monument at Stonehenge was set out by prehistoric surveyors using peg and rope geometry. In ancient Egypt, a rope stretcher would use simple geometry to re-establish boundaries after the floods of the Nile River. The almost perfect squareness and north-south orientation of the Great Pyramid of Giza, built c.2700 BC, the Groma instrument originated in Mesopotamia. The mathematician Liu Hui described ways of measuring distant objects in his work Haidao Suanjing or The Sea Island Mathematical Manual, the Romans recognized land surveyors as a profession. They established the basic measurements under which the Roman Empire was divided, Roman surveyors were known as Gromatici. In medieval Europe, beating the bounds maintained the boundaries of a village or parish and this was the practice of gathering a group of residents and walking around the parish or village to establish a communal memory of the boundaries. Young boys were included to ensure the memory lasted as long as possible, in England, William the Conqueror commissioned the Domesday Book in 1086. It recorded the names of all the owners, the area of land they owned, the quality of the land. It did not include maps showing exact locations, abel Foullon described a plane table in 1551, but it is thought that the instrument was in use earlier as his description is of a developed instrument. Gunters chain was introduced in 1620 by English mathematician Edmund Gunter and it enabled plots of land to be accurately surveyed and plotted for legal and commercial purposes. Leonard Digges described a Theodolite that measured horizontal angles in his book A geometric practice named Pantometria, joshua Habermel created a theodolite with a compass and tripod in 1576. Johnathon Sission was the first to incorporate a telescope on a theodolite in 1725, in the 18th century, modern techniques and instruments for surveying began to be used. Jesse Ramsden introduced the first precision theodolite in 1787 and it was an instrument for measuring angles in the horizontal and vertical planes
5.
Theodolite
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A theodolite /θiːˈɒdəlaɪt/ is a precision instrument for measuring angles in the horizontal and vertical planes. Theodolites are used mainly for surveying applications, and have adapted for specialized purposes such as meteorology. A modern theodolite consists of a telescope mounted within two perpendicular axes, the horizontal or trunnion axis and the zenith axis. A theodolite measures vertical angles as angles between the zenith, forwards or plunged—typically approximately 90 and 270 degrees, when the telescope is pointed at a target object, the angle of each of these axes can be measured with great precision, typically to seconds of arc. A theodolite may be either transit or non-transit, in a transit theodolite, the telescope can be inverted in the vertical plane, whereas the rotation in the same plane is restricted to a semi-circle in a non-transit theodolite. Some types of transit theodolites do not allow the measurement of vertical angles, the builders level is sometimes mistaken for a transit theodolite, but it measures neither horizontal nor vertical angles. It uses a level to set a telescope level to define a line of sight along a horizontal plane. A theodolite is mounted on its head by means of a forced centering plate or tribrach containing four thumbscrews, or in modern theodolites. Before use, a theodolite must be placed vertically above the point to be measured using a plumb bob. The instrument is then set level using leveling footscrews and circular, both axes of a theodolite are equipped with graduated circles that can be read through magnifying lenses. The vertical circle which transits about the horizontal axis should read 90° when the axis is horizontal, or 270° when the instrument is in its second position. Half of the difference between the two positions is called the index error, the horizontal and vertical axes of a theodolite must be perpendicular, if not then a horizontal axis error exists. This can be tested by aligning the tubular spirit bubble parallel to a line between two footscrews and setting the bubble central, a horizontal axis error is present if the bubble runs off central when the tubular spirit bubble is reversed. To adjust, the operator removes 1/2 the amount the bubble has run off using the screw, then re-level, test. If not, then a collimation error exists, index error, horizontal axis error and collimation error are regularly determined by calibration and are removed by mechanical adjustment. Their existence is taken account in the choice of measurement procedure in order to eliminate their effect on the measurement results of the theodolite. The term diopter was used in old texts as a synonym for theodolite. This derives from an astronomical instrument called a dioptra
6.
Tape measure
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A tape measure or measuring tape is a flexible ruler. It consists of a ribbon of cloth, plastic, fibre glass and it is a common measuring tool. Its design allows for a measure of length to be easily carried in pocket or toolkit. Today it is ubiquitous, even appearing in miniature form as a keychain fob, Surveyors use tape measures in lengths of over 100 m. Tape measures that were intended for use in tailoring or dressmaking were made from cloth or plastic. These types of tape measures were mainly used for the measuring of the humans waist line. Today, measuring tapes made for sewing are made of fiberglass, measuring tapes designed for carpentry or construction often use a stiff, curved metallic ribbon that can remain stiff and straight when extended, but retracts into a coil for convenient storage. This type of measure will have a floating tang or hook on the end to aid measuring. The tang is connected to the tape with loose rivets through oval holes, a tape measure of 25 or even 100 feet can wind into a relatively small container. The self-marking tape measure allows the user an accurate one hand measure, the first record of a people using a measuring device was by the Romans using marked strips of leather, but this was more like a regular ruler than a tape measure. On July 14,1868, a patent was filed by one Alvin J. Fellows of New Haven, Fellows rule, although crude and flimsy, was the first attempt to make a spring tape measure. On 3 January 1922, Hiram A. Farrand received the patent he filed in 1919 for his tape measure. Sometime between 1922 and December 1926, Farrand experimented with the help of The Brown Company in Berlin and it is there Hiram and William Wentworth Brown began mass-producing the tape measure. Their product was sold to Stanley Works. The basic design on all modern spring tape measures are built can trace its origins back to an 1868 patent by a New Haven. According to the text of his patent, Fellows tape measure was an improvement on other versions previously designed, the spring tape measure has existed since Fellows patent in 1868, but its usage did not become very popular due to the difficulty in communication from one town to another. In the early 1900s, carpenters began slowly adopting H. A. Farrands design as the one commonly used. With the mass production of the circuit the tape measure has also entered into the digital age with the digital tape measure. Some incorporate a digital screen to give measurement readouts in multiple formats, an early patent for this type of measure was published in 1977
7.
Lead
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Lead is a chemical element with atomic number 82 and symbol Pb. When freshly cut, it is bluish-white, it tarnishes to a dull gray upon exposure to air and it is a soft, malleable, and heavy metal with a density exceeding that of most common materials. Lead has the second-highest atomic number of the stable elements. Lead is a relatively unreactive post-transition metal and its weak metallic character is illustrated by its amphoteric nature and tendency to form covalent bonds. Compounds of lead are found in the +2 oxidation state. Exceptions are mostly limited to organolead compounds, like the lighter members of the group, lead exhibits a tendency to bond to itself, it can form chains, rings, and polyhedral structures. Lead is easily extracted from its ores and was known to people in Western Asia. A principal ore of lead, galena, often bears silver, Lead production declined after the fall of Rome and did not reach comparable levels again until the Industrial Revolution. Nowadays, global production of lead is about ten million tonnes annually, Lead has several properties that make it useful, high density, low melting point, ductility, and relative inertness to oxidation. In the late 19th century, lead was recognized as poisonous, Lead is a neurotoxin that accumulates in soft tissues and bones, damaging the nervous system and causing brain disorders and, in mammals, blood disorders. A lead atom has 82 electrons, arranged in a configuration of 4f145d106s26p2. The combined first and second ionization energies—the total energy required to remove the two 6p electrons—is close to that of tin, leads upper neighbor in group 14. This is unusual since ionization energies generally fall going down a group as an elements outer electrons become more distant from the nucleus, the similarity is caused by the lanthanide contraction—the decrease in element radii from lanthanum to lutetium, and the relatively small radii of the elements after hafnium. The contraction is due to shielding of the nucleus by the lanthanide 4f electrons. The combined first four ionization energies of lead exceed those of tin, for this reason lead, unlike tin, mostly forms compounds in which it has an oxidation state of +2, rather than +4. Relativistic effects, which become particularly prominent at the bottom of the periodic table, as a result, the 6s electrons of lead become reluctant to participate in bonding, a phenomenon called the inert pair effect. A related outcome is that the distance between nearest atoms in crystalline lead is unusually long, the lighter group 14 elements form stable or metastable allotropes having the tetrahedrally coordinated and covalently bonded diamond cubic structure. The energy levels of their outer s- and p-orbitals are close enough to allow mixing into four hybrid sp3 orbitals
8.
Dome
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A dome is an architectural element that resembles the hollow upper half of a sphere. The precise definition has been a matter of controversy, there are also a wide variety of forms and specialized terms to describe them. A dome can rest upon a rotunda or drum, and can be supported by columns or piers that transition to the dome through squinches or pendentives, a lantern may cover an oculus and may itself have another dome. Domes have a long architectural lineage that extends back into prehistory and they have been constructed from mud, snow, stone, wood, brick, concrete, metal, glass, and plastic over the centuries. The symbolism associated with domes includes mortuary, celestial, and governmental traditions that have developed over time. Domes have been found from early Mesopotamia, which may explain the forms spread and they are found in Persian, Hellenistic, Roman, and Chinese architecture in the Ancient world, as well as among a number of contemporary indigenous building traditions. They were popular in Byzantine and medieval Islamic architecture, and there are examples from Western Europe in the Middle Ages. The Renaissance style spread from Italy in the Early modern period, advancements in mathematics, materials, and production techniques since that time resulted in new dome types. The domes of the world can be found over religious buildings, legislative chambers, sports stadiums. The English word dome ultimately derives from the Latin domus —which, up through the Renaissance, labeled a revered house, such as a Domus Dei, or House of God, the French word dosme came to acquire the meaning of a cupola vault, specifically, by 1660. A dome is a rounded vault made of either curved segments or a shell of revolution, sometimes called false domes, corbel domes achieve their shape by extending each horizontal layer of stones inward slightly farther than the lower one until they meet at the top. A false dome may also refer to a wooden dome, true domes are said to be those whose structure is in a state of compression, with constituent elements of wedge-shaped voussoirs, the joints of which align with a central point. The validity of this is unclear, as domes built underground with corbelled stone layers are also in compression from the surrounding earth, as with arches, the springing of a dome is the level from which the dome rises. The top of a dome is the crown, the inner side of a dome is called the intrados and the outer side is called the extrados. The haunch is the part of an arch that lies halfway between the base and the top. The word cupola is another word for dome, and is used for a small dome upon a roof or turret. Cupola has also used to describe the inner side of a dome. Drums, also called tholobates, are cylindrical or polygonal walls with or without windows that support a dome, a tambour or lantern is the equivalent structure over a domes oculus, supporting a cupola
9.
Tower
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A tower is a tall structure, taller than it is wide, often by a significant margin. Towers are distinguished from masts by their lack of guy-wires and are therefore, along with tall buildings, Towers are specifically distinguished from buildings in that they are not built to be habitable but to serve other functions. Towers can be stand alone structures or be supported by adjacent buildings or can be a feature on top of a structure or building. Old English torr is from Latin turris via Old French tor, the Latin term together with Greek τύρσις was loaned from a pre-Indo-European Mediterranean language, connected with the Illyrian toponym Βου-δοργίς. The oldest known may be the stone tower in walls of Neolithic Jericho. Some of the earliest towers were ziggurats, which existed in Sumerian architecture since the 4th millennium BC, the most famous ziggurats include the Sumerian Ziggurat of Ur, built the 3rd millennium BC, and the Etemenanki, one of the most famous examples of Babylonian architecture. The latter was built in Babylon during the 2nd millennium BC and was considered the tallest tower of the ancient world, some of the earliest surviving examples are the broch structures in northern Scotland, which are conical towerhouses. These and other examples from Phoenician and Roman cultures emphasised the use of a tower in fortification, for example, the name of the Moroccan city of Mogador, founded in the first millennium BC, is derived from the Phoenician word for watchtower. The Romans utilised octagonal towers as elements of Diocletians Palace in Croatia, which monument dates to approximately 300 AD, while the Servian Walls, the Chinese used towers as integrated elements of the Great Wall of China in 210 BC during the Qin Dynasty. Towers were also an important element of castles, other well known towers include the Leaning Tower of Pisa in Pisa, Italy built from 1173 until 1372 and the Two Towers in Bologna, Italy built from 1109 until 1119. The Himalayan Towers are stone towers located chiefly in Tibet built approximately 14th to 15th century, up to a certain height, a tower can be made with the supporting structure with parallel sides. However, above a height, the compressive load of the material is exceeded. This can be avoided if the support structure tapers up the building. A second limit is that of buckling—the structure requires sufficient stiffness to avoid breaking under the loads it faces, many very tall towers have their support structures at the periphery of the building, which greatly increases the overall stiffness. A third limit is dynamic, a tower is subject to varying winds, vortex shedding and these are often dealt with through a combination of simple strength and stiffness, as well as in some cases tuned mass dampers to damp out movements. Varying or tapering the outer aspect of the tower with height avoids vibrations due to vortex shedding occurring along the building simultaneously. Although not correctly called towers many modern skyscraper are often called towers, in the United Kingdom, tall domestic buildings are referred to as tower blocks. In the United States, the original World Trade Center had the nickname the Twin Towers, the tower throughout history has provided its users with an advantage in surveying defensive positions and obtaining a better view of the surrounding areas, including battlefields
10.
Inclinometer
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A clinometer or inclinometer is an instrument for measuring angles of slope, elevation or depression of an object with respect to gravity. It is also known as a meter, tilt indicator, slope alert, slope gauge, gradient meter, gradiometer, level gauge, level meter, declinometer. Clinometers measure both inclines and declines using three different units of measure, degrees, percent, and topo, astrolabes are inclinometers that were used for navigation and locating astronomical objects from ancient times to the Renaissance. In aircraft, the ball in turn coordinators or turn and bank indicators is sometimes referred to as an inclinometer. Inclinometers include examples such as Wells in-clinometer, the parts of which are a flat side, or base, on which it stands. The glass face of the disk is surrounded by a scale that marks the angle at which the surface of the liquid stands. A forester using a clinometer makes use of basic trigonometry, first the observer measures a straight-line distance D from some observation point O to the object. Then, using the clinometer, the measures the angle a between O and the top of the object. Then the observer does the same for the angle b between O and the bottom of the object, multiplying D by the tangent of a gives the height of the object above the observer, and by the tangent of b the depth of the object below the observer. Adding the two of course gives the height of the object. The forester stands at a distance from the base of the tree. The most common distances in the United States are 50 feet and 66 feet, to obtain accurate readings it is best to use taped measured distance instead of paced distances. For the most accurate readings it is best to use a distance that is not less than the height of the tree being measured, that is, the observer sights to the top of tree, if total height is the desired measurement. If the desired measurement is merchantable height—that is, the height producing timber that can be sold—the observer sights to a point on the tree above which no more merchantable timber is found, note that the observer should use slopes expressed as a percent. The observer then measures to the bottom of the tree, again using percents, the observer than takes the slope to the top of the tree, and subtracts the slope of the bottom of the tree from it. Note that when the ground slopes downwards, the observer will record a negative slope to the base of the tree, when this is subtracted from the slope to the top of the tree, it is actually being added. These numbers are divided by 100, and multiplied by the distance from the tree. There is still some error in this number, because the distance is measured along the ground, by standing at the base of the tree, the observer should mark his/her eye level
11.
Figure drawing
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A figure drawing is a drawing of the human form in any of its various shapes and postures using any of the drawing media. The term can refer to the act of producing such a drawing. The degree of representation may range from detailed, anatomically correct renderings to loose. A life drawing is a drawing of the figure from observation of a live model. A figure drawing may be a work of art or a figure study done in preparation for a more finished work such as a painting. Figure drawing is arguably the most difficult subject an artist commonly encounters, the human figure is one of the most enduring themes in the visual arts, and the human figure can be the basis of portraiture, illustration, sculpture, medical illustration, and other fields. Artists take a variety of approaches to drawing the human figure and they may draw from live models or from photographs, from skeletal models, or from memory and imagination. Most instruction focuses on the use of models in life drawing courses, in developing the image, some artists focus on the shapes created by the interplay of light and dark values on the surfaces of the body. For those working without visual reference, proportions commonly recommended in figure drawing are and this can be illustrated to students in the classroom using paper plates to visually demonstrate the length of their bodies. An ideal figure, used for an impression of nobility or grace, is drawn at 8 heads tall, a heroic figure used in the depiction of gods and superheroes is eight-and-a-half heads tall. Most of the length comes from a bigger chest and longer legs. Note that these proportions are most useful for a standing model, poses which introduce foreshortening of various body parts will cause them to differ. The French Salon in the 19th century recommended the use of Conté crayons, erasure was not permitted, instead, the artist was expected to describe the figure in light strokes before making darker, more visible marks. A popular modern technique is the use of a stick, prepared from special vines. The charcoal adheres loosely to the paper, allowing very easy erasure, harder compressed charcoal can produce a more deliberate and precise effect, and graduated tones can be produced by smudging with the fingers or with a cylindrical paper tool called a stump. Graphite pencil is also used for figure drawing. For this purpose artists pencils are sold in formulations, ranging from 9B to 1B. Like charcoal, it can be erased and manipulated using a stump, the artist will often start with graphite pencil to sketch or outline the drawing, then the final line work is done with a pen or brush, with permanent ink
