This presentation is for academic purpose
Topics:-
1) Steps in casting
2) Types of pattern
3) Materials used for pattern making
4) Pattern allowances
5)Sand
6) Core and types of core
7) Gating system
8) Chvorinov's rule
9) Freezing ratio
10) Special casting processes
11) Types of furnace
12) Casting Defects
Grain size measurement according to astm standardsJMB
This document discusses three standard ASTM methods for measuring grain size: the comparison method, planimetric/Jeffries' method, and intercept method. The comparison method involves comparing a grain structure to graded images or overlays at 10x magnification, with a repeatability of ±1 grain size number. The planimetric method counts grains within a known area at higher magnifications from 100-500x, achieving ±0.25 grain size units precision. The intercept method counts the number of grains intercepted by a test line, allowing measurement of elongated grains faster than the planimetric method at the same precision of ±0.5 grain size units.
Shear properties of composite materials and ASTM standardsKaustubh Garud
This document discusses different test methods for determining the shear properties of composite materials, including in-plane shear properties and interlaminar shear strength. It describes tests such as the shear test (ASTM D3518), off-axis test, Iosipescu shear test (ASTM D5379), and rail shear method (ASTM D4255) for measuring in-plane shear modulus and strength. It also covers the short-beam shear test (ASTM D2344) for evaluating interlaminar shear strength between laminates using three-point bending of a short beam specimen. Calculations for determining shear stress and strain from the test results are also presented.
Macro structure examination and identification of fracture surfaceLahiru Dilshan
This document summarizes a practical experiment on identifying fracture surfaces of failed materials. The experiment involves examining samples of ductile and brittle materials to observe their macro structures and identify the mode of failure. Ductile materials exhibit necking and a cup and cone fracture surface. Brittle materials break without deformation and have a flat, polished surface. Fatigue fractures show both ductile and brittle regions. Engineering design can be improved by selecting appropriate materials and modifying structures to avoid stress concentrations and prevent different failure modes from occurring.
The document discusses the iron-carbon phase diagram, which shows the different crystal structures that iron takes on at various temperatures depending on the amount of carbon present. It defines various phases including austenite, ferrite, cementite, pearlite, and martensite, and explains how heating and cooling rates affect the microstructure. Heat treatments like tempering, annealing, and normalizing are also summarized in terms of their effects on the steel microstructure.
There are three categories of tempering depending on the temperature range: low, medium, and high temperature tempering. Low temperature tempering from 1-2 hours at up to 250°C is used to reduce brittleness in hardened steels and increases strength and toughness while reducing internal stresses. Medium temperature tempering from 350-500°C produces a Troostite microstructure with good strength, toughness, and hardness. High temperature tempering from 500-650°C produces ultrafine grains in plain carbon and low alloy steels, increasing strength and toughness for machine components.
This document discusses various types of phase transformations in solids, including the mechanisms and processes involved. It describes polymorphic transformations that occur between different crystal structures of a single component system. It also covers precipitation transformations, eutectoid transformations, ordering reactions, and massive transformations, which may involve compositional changes. The document discusses the roles of nucleation and growth in phase transformations, noting that transformations occur through the formation and growth of nuclei rather than an entire system transforming at once. It also addresses concepts like hysteresis, undercooling, and the competing roles of chemical driving force and surface energy during phase transformation processes.
The document discusses various weldability tests used to evaluate the suitability of materials for welding and the performance of welded joints. It describes tests such as the Murex test, Houldcroft test, ring weldability test, controlled thermal severity test, Tekken test, implant test, and Lehigh restraint test. These tests are employed to quantify weldability and provide clues on precautions needed like filler material selection, preheat, and energy input to minimize defects like hot cracking and cold cracking in welded joints.
This presentation is for academic purpose
Topics:-
1) Steps in casting
2) Types of pattern
3) Materials used for pattern making
4) Pattern allowances
5)Sand
6) Core and types of core
7) Gating system
8) Chvorinov's rule
9) Freezing ratio
10) Special casting processes
11) Types of furnace
12) Casting Defects
Grain size measurement according to astm standardsJMB
This document discusses three standard ASTM methods for measuring grain size: the comparison method, planimetric/Jeffries' method, and intercept method. The comparison method involves comparing a grain structure to graded images or overlays at 10x magnification, with a repeatability of ±1 grain size number. The planimetric method counts grains within a known area at higher magnifications from 100-500x, achieving ±0.25 grain size units precision. The intercept method counts the number of grains intercepted by a test line, allowing measurement of elongated grains faster than the planimetric method at the same precision of ±0.5 grain size units.
Shear properties of composite materials and ASTM standardsKaustubh Garud
This document discusses different test methods for determining the shear properties of composite materials, including in-plane shear properties and interlaminar shear strength. It describes tests such as the shear test (ASTM D3518), off-axis test, Iosipescu shear test (ASTM D5379), and rail shear method (ASTM D4255) for measuring in-plane shear modulus and strength. It also covers the short-beam shear test (ASTM D2344) for evaluating interlaminar shear strength between laminates using three-point bending of a short beam specimen. Calculations for determining shear stress and strain from the test results are also presented.
Macro structure examination and identification of fracture surfaceLahiru Dilshan
This document summarizes a practical experiment on identifying fracture surfaces of failed materials. The experiment involves examining samples of ductile and brittle materials to observe their macro structures and identify the mode of failure. Ductile materials exhibit necking and a cup and cone fracture surface. Brittle materials break without deformation and have a flat, polished surface. Fatigue fractures show both ductile and brittle regions. Engineering design can be improved by selecting appropriate materials and modifying structures to avoid stress concentrations and prevent different failure modes from occurring.
The document discusses the iron-carbon phase diagram, which shows the different crystal structures that iron takes on at various temperatures depending on the amount of carbon present. It defines various phases including austenite, ferrite, cementite, pearlite, and martensite, and explains how heating and cooling rates affect the microstructure. Heat treatments like tempering, annealing, and normalizing are also summarized in terms of their effects on the steel microstructure.
There are three categories of tempering depending on the temperature range: low, medium, and high temperature tempering. Low temperature tempering from 1-2 hours at up to 250°C is used to reduce brittleness in hardened steels and increases strength and toughness while reducing internal stresses. Medium temperature tempering from 350-500°C produces a Troostite microstructure with good strength, toughness, and hardness. High temperature tempering from 500-650°C produces ultrafine grains in plain carbon and low alloy steels, increasing strength and toughness for machine components.
This document discusses various types of phase transformations in solids, including the mechanisms and processes involved. It describes polymorphic transformations that occur between different crystal structures of a single component system. It also covers precipitation transformations, eutectoid transformations, ordering reactions, and massive transformations, which may involve compositional changes. The document discusses the roles of nucleation and growth in phase transformations, noting that transformations occur through the formation and growth of nuclei rather than an entire system transforming at once. It also addresses concepts like hysteresis, undercooling, and the competing roles of chemical driving force and surface energy during phase transformation processes.
The document discusses various weldability tests used to evaluate the suitability of materials for welding and the performance of welded joints. It describes tests such as the Murex test, Houldcroft test, ring weldability test, controlled thermal severity test, Tekken test, implant test, and Lehigh restraint test. These tests are employed to quantify weldability and provide clues on precautions needed like filler material selection, preheat, and energy input to minimize defects like hot cracking and cold cracking in welded joints.
The document discusses the iron-carbon phase diagram, which maps the different crystal structures that iron alloys adopt at various temperatures and carbon concentrations. It defines various structures including ferrite, austenite, cementite, pearlite, and martensite. The diagram shows three important reaction lines - the peritectic, eutectic, and eutectoid reactions. It explains how the microstructure of steels with different carbon levels transforms during heating and cooling, resulting in different microstructures like pearlite or ferrite/cementite mixtures. The phase diagram is important for understanding the properties of steels and their heat treatment.
There are several types of imperfections or defects that can occur in crystal structures including point defects, line defects, interfacial defects, and bulk defects. Point defects include vacancies and interstitials which occur naturally in all crystals. Line defects are imperfections where rows of atoms have a differing structure, such as dislocations. Interfacial defects include grain boundaries and twin boundaries. The number and type of defects can be controlled and affect material properties, both positively and negatively.
The document discusses simulation and optimization of metal forming processes. It describes the Center for Precision Forming (CPF) and its work determining sheet material properties through bulge testing, evaluating stamping lubricants using tests like deep drawing, and simulating processes like multi-point cushion systems. CPF uses finite element analysis and experiments to optimize blank holder forces in multi-point cushions and validate simulations. Future work may adjust forces in production to compensate for material variability.
This document provides information on an Indian standard regarding the micrographic determination of apparent grain size in steels. It specifies methods for revealing grain boundaries in ferritic and austenitic steels and for estimating the average grain size. The standard describes determining grain size by comparing micrographs to standard charts, counting the number of grains per unit area, or measuring the mean intercepted segment length. It provides details on specimen selection and preparation, as well as specific etching techniques for revealing grain boundaries in different steel types.
Expandable Pattern Casting and Plaster Mold CastingMarry Sol Lare
Expandable pattern casting and plaster mold casting are two types of expendable mold casting processes. Expandable pattern casting uses an expandable polystyrene pattern that is coated, embedded in sand in a flask, and then vaporized when molten metal is poured, leaving an exact replica of the pattern. Plaster mold casting similarly uses a plaster mold instead of sand and is best for smaller, non-ferrous metal castings due to temperature limitations of plaster. Both methods can produce complex, close-tolerance castings with minimal finishing required.
This document discusses toughness and fracture toughness testing. It defines toughness as the energy absorbed by a material until fracture. Common toughness tests include the Charpy and Izod impact tests, which measure the energy absorbed during a high-velocity impact. However, these tests do not provide data needed for designing with cracks and flaws. Fracture toughness is a better property for design, as it indicates the stress required to propagate a preexisting flaw. The document outlines fracture toughness testing methods like compact tension and single edge notch bending specimens. It also discusses factors that influence fracture toughness values like material thickness, grain orientation, and plane strain versus plane stress conditions.
The document discusses the Jominy end quench test, which is used to measure the hardenability of steels. In the test, a cylindrical steel sample is uniformly heated, then quenched at one end with water to rapidly cool it. Hardness measurements are then taken at intervals along the sample's length from the quenched end. The results show decreasing hardness further from the quenched end, indicating how deep within the material the heat treatment can harden it. Alloying elements like chromium, molybdenum, and manganese can shift the hardness "nose" deeper, improving hardenability by slowing the transformation of austenite. The test provides critical information for selecting ste
Non-Metallic Inclusions in Steel Products
The document discusses non-metallic inclusions in steel products and methods for inclusion assessment, control, and modification. Small amounts of inclusions can significantly impact steel properties like strength and ductility. Inclusions originate from deoxidation reactions and refractory materials. Common inclusions are oxides, sulfides, and carbides. Inclusion size, morphology, distribution, and chemistry all influence steel properties. Inclusion control involves ladle shrouding, argon stirring, and tundish/mold flux design to prevent reoxidation. Calcium treatment is used to modify hard alumina inclusions into spherical calcium aluminate and calcium sulfide inclusions less likely to
Plastic deformation of single crystals can occur through slip or twinning. Slip is the most common mode, occurring when dislocations move through the crystal upon exceeding the elastic limit, resulting in a step formation on the crystal surface. Twinning involves the parallel displacement of planes of atoms in the same direction, resulting in a mirrored atomic arrangement across the twinning plane. Plastic deformation was studied to understand how slip and twinning can lead to permanent shape changes in crystals under stress.
This document summarizes induction hardening and flame hardening surface hardening techniques. It explains that surface hardening increases the hardness of a component's outer surface while leaving the core soft. Induction hardening uses an induction coil to heat a component's surface above the critical temperature, then quenches it to form martensite for hardness. Flame hardening uses an oxy-acetylene flame to selectively harden specific surface areas, then quenches. Both provide wear resistance and control over hardness depth. Induction hardening offers more control and less distortion while flame hardening is economical for large or complex parts.
1) O documento descreve as principais características e fases da Guerra Fria, incluindo a corrida armamentista e espacial entre EUA e URSS.
2) A propaganda de ambos os lados glorificava seus respectivos sistemas ideológicos durante a Guerra Fria.
3) A ascensão de Gorbachev na União Soviética levou a uma transição para uma nova ordem política e econômica, pavimentando o caminho para o fim da Guerra Fria.
This document discusses the complexity of measuring grain size in metals and the evolution of standardization methods. It notes that grains have varying three-dimensional shapes, sizes, and distributions that complicate measurement. Early methods measured planar grain size using number of grains per unit area or average intercept length. Later, ASTM introduced a simplified exponential scale (G number) to specify grain size. Standardization aimed to develop consistent preparation and comparison methods for grain size assessment.
The presentation takes into account widely used surface finishing processes including electroplating, anodizing, alodining, cadmium plating, zinc plating, phosphating, passivation
Weld joint geometry and welding symbolsSudhir Reddy
This document discusses types of welds including groove welds. There are nine categories of welds associated with welding symbols including groove, fillet, plug, stud, spot, seam, backing, surfacing, and flange welds. Groove welds are made in a groove between work pieces and there are eight types: square, scarf, V, bevel, U, J, flare-V, and flare-bevel grooves. The type of groove weld used depends on considerations like joint accessibility, welding process, structural design suitability, and cost.
The document discusses various microstructural transformations in steel alloys as a function of temperature and time. It introduces time-temperature-transformation (TTT) diagrams and continuous cooling transformation (CCT) diagrams as tools to predict microstructures resulting from different heat treatments. TTT diagrams apply to isothermal heat treatments where temperature is held constant, while CCT diagrams apply to continuous cooling processes. The document outlines various microstructures including pearlite, bainite, martensite, and spheroidite and how they form on these diagrams. It also discusses how alloying elements can shift the transformation curves and impact critical cooling rates required to form martensite.
Mumbai University.
Mechanical Engineering
SEM III
Material Technology
MOdule 3
TTT diagram, CCT diagram Hardenability concepts and tests, Graphitization of Iron- Grey iron, white iron, Nodular and malleable irons, their microstructures, properties and applications
This document discusses different types of crystal defects including point defects, line defects, planar defects, and volumetric defects. Point defects include vacancies, self-interstitial atoms, substitutional impurities, and interstitial impurities. Line defects are caused by misalignments of atoms and include edge and screw dislocations. Planar defects form boundaries that separate crystal regions of differing orientations, such as stacking faults, grain boundaries, and twin boundaries. Volumetric defects occur on a larger scale and include voids, porosity, and precipitates.
This document discusses various mechanical properties of materials including elastic deformation, engineering strain, tensile strength, toughness, yielding, modulus of elasticity, Poisson's ratio, ductility, malleability, hardness, and fatigue. It provides definitions and explanations of these key material properties and how they relate to a material's behavior under stress or loads over time.
The document discusses the iron-carbon phase diagram, which maps the different crystal structures that iron alloys adopt at various temperatures and carbon concentrations. It defines various structures including ferrite, austenite, cementite, pearlite, and martensite. The diagram shows three important reaction lines - the peritectic, eutectic, and eutectoid reactions. It explains how the microstructure of steels with different carbon levels transforms during heating and cooling, resulting in different microstructures like pearlite or ferrite/cementite mixtures. The phase diagram is important for understanding the properties of steels and their heat treatment.
There are several types of imperfections or defects that can occur in crystal structures including point defects, line defects, interfacial defects, and bulk defects. Point defects include vacancies and interstitials which occur naturally in all crystals. Line defects are imperfections where rows of atoms have a differing structure, such as dislocations. Interfacial defects include grain boundaries and twin boundaries. The number and type of defects can be controlled and affect material properties, both positively and negatively.
The document discusses simulation and optimization of metal forming processes. It describes the Center for Precision Forming (CPF) and its work determining sheet material properties through bulge testing, evaluating stamping lubricants using tests like deep drawing, and simulating processes like multi-point cushion systems. CPF uses finite element analysis and experiments to optimize blank holder forces in multi-point cushions and validate simulations. Future work may adjust forces in production to compensate for material variability.
This document provides information on an Indian standard regarding the micrographic determination of apparent grain size in steels. It specifies methods for revealing grain boundaries in ferritic and austenitic steels and for estimating the average grain size. The standard describes determining grain size by comparing micrographs to standard charts, counting the number of grains per unit area, or measuring the mean intercepted segment length. It provides details on specimen selection and preparation, as well as specific etching techniques for revealing grain boundaries in different steel types.
Expandable Pattern Casting and Plaster Mold CastingMarry Sol Lare
Expandable pattern casting and plaster mold casting are two types of expendable mold casting processes. Expandable pattern casting uses an expandable polystyrene pattern that is coated, embedded in sand in a flask, and then vaporized when molten metal is poured, leaving an exact replica of the pattern. Plaster mold casting similarly uses a plaster mold instead of sand and is best for smaller, non-ferrous metal castings due to temperature limitations of plaster. Both methods can produce complex, close-tolerance castings with minimal finishing required.
This document discusses toughness and fracture toughness testing. It defines toughness as the energy absorbed by a material until fracture. Common toughness tests include the Charpy and Izod impact tests, which measure the energy absorbed during a high-velocity impact. However, these tests do not provide data needed for designing with cracks and flaws. Fracture toughness is a better property for design, as it indicates the stress required to propagate a preexisting flaw. The document outlines fracture toughness testing methods like compact tension and single edge notch bending specimens. It also discusses factors that influence fracture toughness values like material thickness, grain orientation, and plane strain versus plane stress conditions.
The document discusses the Jominy end quench test, which is used to measure the hardenability of steels. In the test, a cylindrical steel sample is uniformly heated, then quenched at one end with water to rapidly cool it. Hardness measurements are then taken at intervals along the sample's length from the quenched end. The results show decreasing hardness further from the quenched end, indicating how deep within the material the heat treatment can harden it. Alloying elements like chromium, molybdenum, and manganese can shift the hardness "nose" deeper, improving hardenability by slowing the transformation of austenite. The test provides critical information for selecting ste
Non-Metallic Inclusions in Steel Products
The document discusses non-metallic inclusions in steel products and methods for inclusion assessment, control, and modification. Small amounts of inclusions can significantly impact steel properties like strength and ductility. Inclusions originate from deoxidation reactions and refractory materials. Common inclusions are oxides, sulfides, and carbides. Inclusion size, morphology, distribution, and chemistry all influence steel properties. Inclusion control involves ladle shrouding, argon stirring, and tundish/mold flux design to prevent reoxidation. Calcium treatment is used to modify hard alumina inclusions into spherical calcium aluminate and calcium sulfide inclusions less likely to
Plastic deformation of single crystals can occur through slip or twinning. Slip is the most common mode, occurring when dislocations move through the crystal upon exceeding the elastic limit, resulting in a step formation on the crystal surface. Twinning involves the parallel displacement of planes of atoms in the same direction, resulting in a mirrored atomic arrangement across the twinning plane. Plastic deformation was studied to understand how slip and twinning can lead to permanent shape changes in crystals under stress.
This document summarizes induction hardening and flame hardening surface hardening techniques. It explains that surface hardening increases the hardness of a component's outer surface while leaving the core soft. Induction hardening uses an induction coil to heat a component's surface above the critical temperature, then quenches it to form martensite for hardness. Flame hardening uses an oxy-acetylene flame to selectively harden specific surface areas, then quenches. Both provide wear resistance and control over hardness depth. Induction hardening offers more control and less distortion while flame hardening is economical for large or complex parts.
1) O documento descreve as principais características e fases da Guerra Fria, incluindo a corrida armamentista e espacial entre EUA e URSS.
2) A propaganda de ambos os lados glorificava seus respectivos sistemas ideológicos durante a Guerra Fria.
3) A ascensão de Gorbachev na União Soviética levou a uma transição para uma nova ordem política e econômica, pavimentando o caminho para o fim da Guerra Fria.
This document discusses the complexity of measuring grain size in metals and the evolution of standardization methods. It notes that grains have varying three-dimensional shapes, sizes, and distributions that complicate measurement. Early methods measured planar grain size using number of grains per unit area or average intercept length. Later, ASTM introduced a simplified exponential scale (G number) to specify grain size. Standardization aimed to develop consistent preparation and comparison methods for grain size assessment.
The presentation takes into account widely used surface finishing processes including electroplating, anodizing, alodining, cadmium plating, zinc plating, phosphating, passivation
Weld joint geometry and welding symbolsSudhir Reddy
This document discusses types of welds including groove welds. There are nine categories of welds associated with welding symbols including groove, fillet, plug, stud, spot, seam, backing, surfacing, and flange welds. Groove welds are made in a groove between work pieces and there are eight types: square, scarf, V, bevel, U, J, flare-V, and flare-bevel grooves. The type of groove weld used depends on considerations like joint accessibility, welding process, structural design suitability, and cost.
The document discusses various microstructural transformations in steel alloys as a function of temperature and time. It introduces time-temperature-transformation (TTT) diagrams and continuous cooling transformation (CCT) diagrams as tools to predict microstructures resulting from different heat treatments. TTT diagrams apply to isothermal heat treatments where temperature is held constant, while CCT diagrams apply to continuous cooling processes. The document outlines various microstructures including pearlite, bainite, martensite, and spheroidite and how they form on these diagrams. It also discusses how alloying elements can shift the transformation curves and impact critical cooling rates required to form martensite.
Mumbai University.
Mechanical Engineering
SEM III
Material Technology
MOdule 3
TTT diagram, CCT diagram Hardenability concepts and tests, Graphitization of Iron- Grey iron, white iron, Nodular and malleable irons, their microstructures, properties and applications
This document discusses different types of crystal defects including point defects, line defects, planar defects, and volumetric defects. Point defects include vacancies, self-interstitial atoms, substitutional impurities, and interstitial impurities. Line defects are caused by misalignments of atoms and include edge and screw dislocations. Planar defects form boundaries that separate crystal regions of differing orientations, such as stacking faults, grain boundaries, and twin boundaries. Volumetric defects occur on a larger scale and include voids, porosity, and precipitates.
This document discusses various mechanical properties of materials including elastic deformation, engineering strain, tensile strength, toughness, yielding, modulus of elasticity, Poisson's ratio, ductility, malleability, hardness, and fatigue. It provides definitions and explanations of these key material properties and how they relate to a material's behavior under stress or loads over time.
Los niños de un jardín de infantes inventaron una historia sobre dragones basada en imágenes que la maestra les mostró. Trabajaron juntos describiendo detalles de las imágenes y desarrollando una trama con inicio, nudo y final. La historia trata de una princesa amenazada por un dragón verde llamado Valentín Federico hasta que es rescatada por un caballero llamado Pepe montado en un caballo llamado "Correr del Campo". Pepe mata al dragón con su lanza y luego se enamora de la princes
Sant Jordi es una leyenda. Ángela les contó la leyenda de Sant Jordi por la tarde a los niños con todos sus personajes y disfraces. Los niños la pasaron muy bien escuchando la historia.
El documento lista los nombres de 26 jugadores del FC Barcelona en orden alfabético, incluyendo a Éric Abidal, Sergio Busquets, Carles Puyol, Daniel Alves, Adriano Correia, Jeffren Suárez, Gabriel Alejandro Milito, Xavi Hernández, Andrés Iniesta, Bojan Krkic, Seydou Keita, Víctor Valdés, Lionel Messi, Andreu Fontàs, José Manuel Pinto, Gerard Piqué, Pedro Rodríguez, Javier Mascherano, Josep Guardiola, David Villa, Maxwell Scherrer, Ibra
Poemes infantils i juvenils per gaudir del Dia del Llibre i el Dia de Sant Jordi. Editat al blog "Poesia Infantil i Juvenil"
Feliç Sant Jordi 2011 i bona lectura
Ibiza es una pequeña isla con una larga historia que ha sido habitada sucesivamente por cartagineses, fenicios, romanos, vándalos, bizantinos y musulmanes, dejando atrás una rica cultura e influencias en su gastronomía y monumentos. La isla ofrece playas, pueblos pesqueros, salinas y una cultura única que merece ser conocida y respetada para poder disfrutar plenamente de su belleza.
El documento describe la historia de la exploración espacial, desde los primeros telescopios de Galileo hasta las misiones espaciales modernas. Explica la evolución de los telescopios ópticos y los principales tipos como reflectores, refractores y cassegrain. También describe importantes sondas espaciales como Voyager 1, Cassini-Huygens y New Horizons, así como los cohetes de lanzamiento y las dos únicas estaciones espaciales tripuladas actualmente en órbita, la Estación Espacial Internacional y la Est
Se han detectado más de 2030 exoplanetas orbitando otras estrellas desde la primera detección en 1995. La principal herramienta de detección es el telescopio espacial Kepler. Algunos exoplanetas se encuentran dentro de la zona de habitabilidad de su estrella donde podrían existir condiciones similares a la Tierra, como Kepler-438b con un índice de similitud terrestre de 0.88 o el posible exoplaneta Koi-4878.01 con un índice de 0.98 que podría ser una segunda Tierra.
El documento describe las características de los cuerpos del sistema solar como el Sol, planetas como Mercurio, Venus, Tierra, Marte, Júpiter, Saturno, Urano y Neptuno, así como Plutón y otros planetas enanos. También habla sobre cometas, asteroides y meteoritos, cuerpos menores que proporcionan información sobre el origen y evolución del sistema solar.
1. Declaració Universal
dels Drets Humans
Resumida i en llenguatge senzill
Declaració
Universal
dels
Drets
Humans
La construcció d’un món solidari, sense injustícies ni violència, només és possible
si totes les nacions i tots els individus ens esforcem a promoure, arreu del món, els drets
i les llibertats d’aquesta Declaració
(Adaptació del Preàmbul de la Declaració)
Article 1: Tots els éssers humans naixem lliures, amb els Article 6: Tots els nostres drets han de ser reconeguts a tot
mateixos drets i amb la mateixa dignitat. Com que tenim raó arreu.
i consciència, ens hem de tractar sempre amb respecte.
Article 7: La llei és la mateixa per a tothom. No se'ns pot
Article 2: Els drets que proclama aquesta Declaració són aplicar de forma diferent.
per a tothom. Encara que parlem una altra llengua, encara
que tinguem el color de la pell diferent, encara que pensem Article 8: Quan algú no respecta els nostres drets podem
d'una altra manera, encara que sigui una altra la nostra religió, demanar la protecció de la justícia.
tant si som pobres com si som rics com si som d'un altre
país. Article 9: Ningú no té dret, arbitràriament, a detenir-nos, a
mantenir-nos a la presó ni a expulsar-nos del país on vivim.
Article 3: Tots tenim dret a viure. A viure lliurement i amb
seguretat. Article 10: Si hem de ser jutjats ha de ser públicament. I
aquells que ens jutgin han de ser completament imparcials.
Article 4: Ningú no ens pot esclavitzar. L'esclavitud està
prohibida en tots els casos. Article 11: Si som acusats, sempre tenim dret a defensar-
nos. S'ha d'admetre que som innocents mentre no es pugui
Article 5: Ningú no té dret a torturar-nos ni a tractar-nos de provar que som culpables. Ningú no té dret a condemnar-
forma cruel, inhumana o degradant. nos ni a castigar-nos per coses que no hem fet.
2. Article 12: Ningú no pot ficar-se arbitràriament en la nostra nos de tots els avantatges socials, culturals i econòmics per
vida privada, en la nostra família, la nostra casa o la nostra poder viure dignament.
correspondència.
Article 23: Tenim dret a treballar, a triar lliurement una feina i
Article 13: Tenim dret a entrar i sortir del nostre país quan a rebre un sou que ens permeti viure dignament, a nosaltres
vulguem. i a la nostra família. Totes les persones que facin el mateix
treball, tenen dret, sense cap discriminació, al mateix sou. Si
Article 14: Si ens persegueixen, tenim dret a anar a un altre treballem, tenim dret a agrupar-nos per defensar els nostres
país i demanar que ens protegeixin. Però perdem aquest interessos.
dret si no respectem els articles d'aquesta Declaració.
Article 24: Tots tenim dret a descansar. Per tant, la jornada
Article 15: Tenim dret a pertànyer a un país. I, si desitgem laboral no ha de ser excessivament llarga i, periòdicament,
pertànyer a un altre país, ningú no pot, arbitràriament, impedir- hem de poder tenir vacances pagades.
nos-ho.
Article 25: Tant nosaltres com la nostra família tenim dret a
Article 16: Quan tenim edat de casar-nos, tenim dret a fer-ho un nivell de vida que ens asseguri l'alimentació, el vestit,
sigui quina sigui la nostra raça, el nostre país d'origen o la l'habitatge i l'assistència en cas de malaltia.
nostra religió. Les dones i els homes tenim els mateixos Tenim dret a ser ajudats si no podem treballar, ja sigui perquè
drets quan som casats i quan ens separem. No hi ha ningú no hi ha feina, perquè estem malalts, perquè som massa
que ens pugui obligar a casar-nos i, si ho fem, el govern del grans o per qualsevol altra raó independent de la nostra
nostre país ha de protegir la nostra família. voluntat.
Tots els nens i nenes tenen els mateixos drets, encara que
Article 17: Com tothom, tenim dret a tenir les nostres coses, els seus pares no estiguin casats.
i ningú no té dret a prendre'ns-les.
Article 26: Tenim dret a anar a l'escola, i a beneficiar-nos de
Article 18: Tenim dret a pensar el que volem i a canviar de l'escola obligatòria sense haver de pagar res.
manera de pensar. També tenim dret a triar lliurement la L'escola ha de fomentar la convivència i el desenvolupament
religió que volem, a canviar de religió i a practicar-la com ens dels talents de cadascú. Els pares tenen dret a triar el tipus
sembli, sols o amb d'altres persones. d'educació dels seus fills.
Article 19: Tots tenim dret a la llibertat d'opinió i d'expressió. Article 27: Tots tenim dret a participar i beneficiar-nos tant de
Tenim dret a intercanviar idees amb les persones d'altres la vida cultural com del progrés científic de la societat en què
països sense que les fronteres ens ho impedeixin. vivim.
Article 20: Tots tenim dret a organitzar grups i reunions, i a Article 28: Per tal que tots els drets i les llibertats de què hem
participar-hi de manera pacífica. Ningú no ens pot obligar a parlat fins ara puguin ser protegits adequadament, cal que
formar part d'un grup. existeixi un ordre social i internacional que ho faci possible.
Article 21: Tenim dret a participar activament en les decisions Article 29: Tots tenim deures en relació amb les persones
del nostre país, directament o escollint representants que que ens envolten, a les quals, d'altra banda, necessitem per
tinguin les nostres idees i votant lliurement per indicar la desenvolupar-nos plenament. La nostra llibertat i els nostres
nostra elecció. drets només estan limitats pel reconeixement i el respecte
Per poder escollir els nostres governants, periòdicament necessari a la llibertat i els drets dels altres.
s'han de fer eleccions no manipulades en les que tothom
pugui votar lliurement. Article 30: Cap Estat, cap grup, cap ésser humà, pot utilitzar
cap principi d'aquesta Declaració per suprimir el drets i
Article 22: Cadascú de nosaltres tenim dret a beneficiar- llibertats que s'hi proclamen.