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Basic Technology (Introductory Technology)

basic technology (Secondary School)

Rubber and plastics

Rubber vs. Plastic In the past, people have seen the progress of technology. From the simple usage of wood and cement to the invention of metal, mankind has really made great progress to become what they are today. Along with this progress are some changes to their lifestyle. These changes were brought about by the materials surrounding them, and two materials that revolutionized man’s life today is rubber and plastic.   It is quite easy to differentiate between the two. By simply looking at each material, one can immediately tell that a particular thing, or object, is made of rubber and not plastic, or vice versa. The only confusion between the two is when the term polymer is used. Yes, polymer as a term that greatly denotes plastics, but nonetheless, this term also describes the characteristic of rubbers. Although rubber is more of the specific elastomer (a viscous or elastic… Read More »Rubber and plastics

basic technology (Secondary School)

Properties of ceramics and glass

Ceramic Material Characteristics Ceramics and glasses are inorganic, nonmetallic materials consisting of metallic and nonmetallic elements bonded primarily with ionic and covalent bonds. These high strength bonds give rise to the special characteristics of these materials. They occupy a unique place in the spectrum of engineered materials offering many desirable alternatives to the metals and polymers in common usage. General Characteristics of Structural Materials Characteristic Ceramics Metals Polymers Density Low to High Low to High Low Hardness High Medium Low Tensile Strength Low to Medium High Low Compressive Strength High Medium to High Low to Medium Young’s Modulus Medium to High Low to High Low Melting Point High Low to High Low Dimensional Stability High Low to Medium Low Thermal Expansion Low to Medium Medium to High High Thermal Conductivity Medium Medium to High Low Thermal Shock Low Medium to High High Electrical Resistance High Low High Chemical Resistance High… Read More »Properties of ceramics and glass

basic technology (Secondary School)

Metals

Metals – Ferrous and Non Ferrous 1. Metals. Exercise 1: Make a list of all the different metals that you know about. 2. Metals. Two main groups, 1.Ferrous. 2.Non-Ferrous. 3. Metals Ferrous Pure Ferrous Metals Non Ferrous Ferrous Alloys Pure Non Ferrous Metals Copper Non Ferrous Alloys Alum. Brass Bronze Solder Zinc Tin High Speed Steel Copper + Zinc Copper + Tin Lead + Tin Lead Silver High Speed Steel Cutting Tools Gold Mercury Steel Iron Mercury is the only non ferrous metal that is liquid at room temperature. Alloying. 4. Ferrous Metals. Ferrous metals: Ferrous metals are metals that consist mostly of iron and small amounts of other elements. Ferrous metals are prone to rusting if exposed to moisture. Ferrous metals can also be picked up by a magnet. The rusting and magnetic properties in ferrous metals are both down due to the iron. Typical ferrous metals include mild steel, cast iron… Read More »Metals

basic technology (Secondary School)

Properties of metals

Differences and similarities between metals and non-metals Properties: Metals: Non-metals: Strong Brittle Malleable and ductile Brittle React with oxygen to form basic oxides React with oxygen to form acidic oxides Sonorous Dull sound when hit with hammer High melting and boiling points Low melting and boiling points Good conductors of electricity Poor conductors of electricity Good conductors of heat Poor conductors of heat Mainly solids at room temp. Exception mercury – liquid at room temp. Solids, liquids and gases at room.temp. Shiny when polished Dull looking When they form ions, the ions are positive When they form ions, the ions are negative – except hydrogen that forms a positive ion, H+. High density Low density   Common Metals and Non-Metals Metals: Non-metals: Calcium Sulphur Potassium Oxygen Lead Chlorine Copper Hydrogen Aluminium Bromine Zinc Nitrogen Lithium Helium   Uses of metals and non-metals Metals The uses of metals are related to… Read More »Properties of metals

basic technology (Secondary School)

Wood

identification of wood up vote13down voteaccepted Hardwood is usually from a deciduous tree and softwood is usually from a coniferous one. Hardwoods typically have a higher density(hence hardwood). For the most part that is the general accepted (although broad) definition and yes there are several exceptions. Little more than that please Much like identifying wood species; determining if a particular wood is soft or hard depends on the kind of tree it came from. More specifically Hardwood Comes from dicot angiosperm which mean the tree reproduces with flowers and most have broad leaves that are shed in response to natural climate change or drought. There are several species of evergreen that fit into this category as well. These evergreens are usually located in more tropical/subtropical zones. Hardwood trees have large vessels for transporting water. These pores are responsible for the grain appearance in hardwood and are best seen under microscope. Softwood Almost all softwood… Read More »Wood

basic technology (Secondary School)

Properties of materials

What is wood? You often hear people grumbling about money and all kinds of other things that “don’t grow on trees”; the great thing about wood is that it does grow on trees—or, more specifically, in their trunks and branches. Structure of wood Take a tree and peel off the outer “skin” or bark and what you’ll find is two kinds of wood. Closest to the edge there’s a moist, light, living layer called sapwood packed with tubes called xylem that help a tree pipe water and nutrients up from its roots to its leaves; inside the sapwood there’s a much darker, harder, part of the tree called the heartwood, which is dead, where the xylem tubes have blocked up with resins or gums and stopped working.   Around the outer edge of the sapwood (and the trunk) is a thin active layer called the cambium where the tree is actually growing outward by a little bit each year,… Read More »Properties of materials

basic technology (Secondary School)

Workshop safety

Rules and Regulations 1) Never work alone in the workshop, work at least in pairs. This is so because in case of industrial/workshop accident the other partner will be a helper (Ecclesiastes 4:9-10) it’s all about Teamwork. 2) Think about what you are doing; think before you start a job and during the entire time you are doing it. Remember that your own personal caution is of more value to you than all the safeguards that can be set up. 3) Know where the main switch is. This stops processes immediately should anything go wrong in the industry. 4) Smoking and carrying matches or naked flames by employees is prohibited in and about the complex except in zone specifically designed for such purposes. Safety section must see that “No smoking” signs are placed in and about their area to warn the employee and visitors. 5) When work is being done… Read More »Workshop safety

basic technology (Secondary School)

Work Shop Safety

Workshop rules and safety considerations Workshop safety is everyone’s responsibility, the following rules have been put in place to ensure the safety of all students and staff. Please read the safety rules carefully before entering the workshop. Workshop rules Student affected by drugs or alcohol are not permittedin the workshop Students with any health problems that may affect workplace safety (e.g. medication, epileptic fits) must report these conditions to the workshop staff Notify the workshop staff of your arrival No food or drink in the workshop Wear the correct protective equipment for the tools you are using – ask if in doubt All chemicals (e.g. glues and paints) must be checked through Chemwatch and with workshop staff before use Immediately notify the workshop supervisor of any faulty or broken equipment Ask how to use the tools safely Make sure your work piece is fixed securely before work commences Keep leads up… Read More »Work Shop Safety

basic technology (Secondary School)

Technology

Technology (“science of craft”, from Greek τέχνη, techne, “art, skill, cunning of hand”; and -λογία, -logia[2]) is the collection of techniques, skills, methods, and processes used in the production of goods or services or in the accomplishment of objectives, such as scientific investigation. Technology can be the knowledge of techniques, processes, and the like, or it can be embedded in machines to allow for operation without detailed knowledge of their workings.   The simplest form of technology is the development and use of basic tools. The prehistoric discovery of how to control fire and the later Neolithic Revolution increased the available sources of food, and the invention of the wheel helped humans to travel in and control their environment. Developments in historic times, including the printing press, the telephone, and the Internet, have lessened physical barriers to communication and allowed humans to interact freely on a global scale. The steady progress of military technology has brought weapons of ever-increasing destructive power, from clubs to nuclear weapons.   Technology has many effects. It has helped develop more advanced economies (including today’s global economy) and has allowed the rise of a leisure class. Many technological processes produce… Read More »Technology

basic technology (Secondary School)

Orthographic Drawing

Imagine you are shopping for a chair to go in your living room. You find the perfect one, but it is way too expensive. Fortunately, you have a cousin that builds furniture. Maybe he can build the chair for you! Describing the chair over the phone was more than a challenge. Your cousin suggests you send him pictures of the chair from multiple angles, along with the measurements. This experience illustrates the process that a furniture designer must go through in order for the manufacturer to create the chair as intended. Three-dimensional drawings can be used to show the overall concept and design, but they are often not clear or detailed enough. Orthographic drawings can help to overcome those challenges. An orthographic drawing represents a three-dimensional object using several two-dimensional views of the object. It is also known as an orthographic projection. For example, you can see in this image the front,… Read More »Orthographic Drawing

basic technology (Secondary School)

Perspective Drawing

A mathematical system for representing three-dimensional objects and space on a two-dimensional surface by means of intersecting lines that are drawn vertically and horizontally and that radiate from one point on a horizon line… Although this definition sounds complicated, the concept is relatively simple. One point perspective is a drawing method that shows how things appear to get smaller as they get further away, converging towards a single ‘vanishing point’ on the horizon line. It is a way of drawing objects upon a flat piece of paper (or other drawing surface) so that they look three-dimensional and realistic. Drawing in one point perspective is usually appropriate when the subject is viewed ‘front-on’ (such as when looking directly at the face of a cube or the wall of building) or when looking directly down something long, like a road or railway track. It is popular drawing method with architects and illustrators,… Read More »Perspective Drawing

basic technology (Secondary School)

Oblique Drawing

Definition of oblique drawing  a projective drawing of which the frontal lines are given in true proportions and relations and all others at suitable angles other than 90 degrees without regard to the rules of linear perspe ‘Cabinet Oblique’ In Cabinet obliquethe scale (depth) is halved whilst in Cavalier oblique the depth scale is the same as in the X and Y directions. One remaining drawing conventions is Oblique drawing –In this convention the angles used are 45 degrees and 90 degrees.  The only difference between the two named styles is in the scale of the dimension going away from the viewer. This first example is Cavalier Obliqueand shows the full scale (1:1) in the axis. This drawing (shown to the left) is symmetric about the horizontal centre-line.Centre-lines are chain-dotted and are used for symmetric objects, and also for  showing the centre of circles and holes. Drawing dimensions should generally be done directly to… Read More »Oblique Drawing

basic technology (Secondary School)

Drawing Practices

Isometric drawing; A pictorial representation of an object in which all three dimensions are drawn at full scale rather than foreshortening them to the true projection. An isometric drawing looks like an isometric projection but all its lines parallel to the three major axes are measurable. Isometric drawing, also called isometric projection, method of graphic representation of three-dimensional objects, used by engineers, technical illustrators, and, occasionally, architects. The technique is intended to combine the illusion of depth, as in a perspective rendering, with the undistorted presentation of the object’s principal dimensions—that is, those parallel to a chosen set of three mutually perpendicular coordinate axes.   Encyclopædia Britannica, Inc. The isometric is one class of orthographic projections. (In making an orthographic projection, any point in the object is mapped onto the drawing by dropping a perpendicular from that point to the plane of the drawing.) An isometric projection results if the plane is oriented so that it makes equal angles (hence “isometric,”… Read More »Drawing Practices

basic technology (Secondary School)

Metal Processing

Metal Alloys An alloy is a material made by melting one or more metals together with other elements. This is an alphabetical list of alloys grouped according to the base metal of the alloy. Some alloys are listed under more than one element, since the composition of the alloy may vary such that one element is present in a higher concentration than the others. ALUMINUM ALLOYS AA-8000: used for building wire Al-Li (aluminum, lithium, sometimes mercury) Alnico (aluminum, nickel, copper) Duralumin (copper, aluminum) Magnalium (aluminum, 5% magnesium) Magnox (magnesium oxide, aluminum) Nambe (aluminum plus seven other unspecified metals) Silumin (aluminum, silicon) Zamak (zinc, aluminum, magnesium, copper) Aluminum forms other complex alloys with magnesium, manganese, and platinum   Properties of metals Metals: Non-metals: Strong Brittle Malleable and ductile Brittle React with oxygen to form basic oxides React with oxygen to form acidic oxides Sonorous Dull sound when hit with hammer High melting and boiling… Read More »Metal Processing

basic technology (Secondary School)

Processing of wood

Defects in wood: wood defects Timber is far from being a stable and consistent material. One of the biggest challenges of working with timber is learning to work within the constraints of a timber’s. The following are a list of the most common wood defects. BOW (BOWING) The curvature of a piece of sawn timber in the direction of its length, cf. Spring and Curvature. BOXED HEART A term used when the heart is enclosed within the four surfaces of a piece of sawn timber. Well boxed Heart means that the heart is enclosed within the four surfaces of piece of sawn or hewn timber throughout its entire length, and is reasonably well centered at both ends. CHECKS Are small separations of the wood fibers in a longitudinal Wood Defects direction, not penetrating as far as the opposite or adjoining side of a piece of sawn timber; they usually result… Read More »Processing of wood

basic technology (Secondary School)

Processing Wood

What is wood conversion? Wood conversion is the process where a newly felled tree is converted into workable lumber. There are many different cuts that can be used to convert a downed tree to lumber. FULL ANSWER If the lumber is going to be used for construction, the wood is cut plain or through and through. This is less expensive to cut, and while it does produce increased chances of cupping, the wood is stronger when used properly. If the lumber is intended for decorative purposes, it is cut quartered or rift sawn. This is more expensive and produces more waste; however, the wood is much more decorative in appearance and is less prone to both cupping and expansion. Conversion and processing Conversion The conversion of timber is a phrase usually used in reference to turning a log into a pile of boards/planks. This is done using a saw mill of… Read More »Processing Wood

basic technology (Secondary School)

Processing of Wood

Wood processing is an engineering discipline comprising the production of forest products, such as pulp and paper, construction materials, and tall oil. Paper engineering is a subfield of wood processing. The major wood product categories are: sawn timber, wood-based panels, wood chips, paper and paper products and miscellaneous others including poles and railway sleepers. Forest product processing technologies have undergone extraordinary advances in some of the above categories. Improvements have been achieved in recovery rates, durability and protection, greater utilization of NTFPs such as various grain stalks and bamboo, and the development of new products such as reconstituted wood-panels. Progress has not been homogenous in all the forest product utilization categories. Although there is little information available on the subjects of technology acquisition, adaptation and innovation for the forest-based industrial sector, it is clear that sawmilling has been far less affected by the spread of innovations than the manufacturing of panel products.[1] Wood processing produces additives for… Read More »Processing of Wood

basic technology (Secondary School)

Carrier opportunities in technology

We use technology more than ever these days to stay connected to our friends and family, get up-to-date on the latest and greatest happenings in our world and sometimes just to pass the time. With all the computers, tablets, smartphones and other high-tech devices our society is dependent on, we need the skills of professionals in technology jobs to make our obsession with tech possible. The Labor Department predicts that tech jobs will grow faster than the average for all jobs at a rate of 12 percent this decade, but it’s not just hiring demand that makes this industry one to watch. U.S. News’ Best Technology Jobs of 2017 are also high-paying jobs that boast low unemployment rates. Check out what makes these gigs so great, and read more on how we rank the best jobs. Computer Systems Analyst Computer systems analysts must have a diverse skill set. The position… Read More »Carrier opportunities in technology

basic technology (Secondary School)

VOLTAGE, RESISTANCE, INDUCTANCE AND CAPACITANCE CONTENT

VOLTAGE (POTENTIAL DIFFRENCE) Difference between points in electric field: the work done in moving a unit electric charge between two points in an electric field. Electric potential: electric potential expressed in volts. It is measured in volts. The instrument for measurement is a voltmeter.   RESISTANCE Resistance is the opposition that a circuit, component, or substance presents to the flow of electricity. Symbol R electricity source of resistance: something that is a source of opposition to the flow of electricity, e.g. a resistor. It is measured in ohms. The instrument for measurement is a ohmmeter   INDUCTORS An inductor is a circuit element which has the ability to produce an induced voltage in response to changing current. A device, usually a compact coil, which opposes any change in a circuit current is called an inductor.  Inductance is a measure of this ability.   When an electric current is passed through… Read More »VOLTAGE, RESISTANCE, INDUCTANCE AND CAPACITANCE CONTENT

basic technology (Secondary School)

BASIC COMPONENTS OF ELECTRIC CIRCUIT

ELECTRIC CIRCUITS Electric circuit can be defined as the path provided for easy flow of electric current.  It is for conversion of the electric current into useful purposes such as lighting and heating.  Electric circuit is connected or fitted with devices that control and measure the current and energy used in the process. Simple electric circuit   BASIC COMPONENTS OF ELECTRIC CIRCUIT THE CELL OR BATTERY The cell or battery is to push the free electrons round the circuit.  The work done when one coulomb of charge moves from one point to the other in the conductor is known as potential difference (p.d).  It is measured in volt.  The instrument used for measuring the potential difference is called the voltmeter (v).The ammeter (A) is used to measure the current flow.  Current is represented by the symbol I and it is measured in Amperes.  The instrument used for measuring current is… Read More »BASIC COMPONENTS OF ELECTRIC CIRCUIT

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