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1a. Technology is the application of knowledge, tools, and skills to solve problems and extend human capabilities. b. A technology system is a group of.

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Presentation on theme: "1a. Technology is the application of knowledge, tools, and skills to solve problems and extend human capabilities. b. A technology system is a group of."— Presentation transcript:

1 1a. Technology is the application of knowledge, tools, and skills to solve problems and extend human capabilities. b. A technology system is a group of subsystems working together to solve problems and extend human capabilities. c.An artifact is something made by humans for a practical purpose.

2 Question 2: 12 steps of design process. 1.Defining a problem 2.Identifying criteria and specifying constraints 3.Researching and generating ideas 4.Brainstorming 5.Exploring possibilities 6.Selecting an approach 7.Developing a design proposal – purpose is to communicate final design and steps to construct it. 8.Making a model or prototype 9.Testing and evaluating the design, using specifications 10.Refining the design 11.Creating or making it 12.Communicating processes and results

3 3. Principle: a law of nature underlying the working of an artificial device 4.Mechanical technology: the technology of putting together mechanical parts to produce, control, and transmit motion. 5.Machines: artifacts that transmit or change the application of power, force, or motion. 6.Machines can be simple or complex. Complex machines are made up of simple machines. 7.Core technologies are the “building blocks” of all technology.

4 8a. Door latch: mechanical, structural, material b. Fan: mechanical, electrical, structural, material c. Crankshaft: mechanical, material, structural d. Battery: structural, electrical, material e. Thermostat: material, electronic, thermal f. Cylinder: structural, material g. Gas tank: structural, material 9.Simple machines work on the principle of the lever and the inclined plane. 10. Lever: lever, pulley, wheel and axle; Inclined plane: inclined plane, wedge, screw

5 11 12 F x d = WORK 13 Wo / Wi = EFFICIENCY 14 A systematic application is an organized or established procedure, a set of steps. 15 “A” would be easier to push down. 16 The load of “B” will travel the greater distance. 17 A force multiplier is a machine that increases the force applied to the work at hand. A distance multiplier is a machine that increases the distance the load moves. “A” above is the force multiplier. “B” is the distance multiplier.

6 18. Mechanical Advantage (M.A.) is the number of times a mechanical device multiplies an applied force. The equation for M.A. is DF / DL and L / F. 19. A pulley is a mechanical device that is an adaptation of a wheel and axle. To find M.A. of a pulley, count the total number of strands supporting the load. 20. A fixed pulley is a pulley attached or fixed to a strong structural member (system does not move). MA = 1. 21. A movable pulley is a pulley that is free to move since it is attached with a strand to a fixed structural member. MA = 2. 22. A block and tackle is a system of three pulleys: 2 fixed and 1 movable. MA = 3. FIXEDMOVABLEBLOCK and TACKLE

7 23.Electrical Technology: the technology of producing, storing, controlling, transmitting and getting work from electrical energy. 24. Ohm’s Law –V = I x R Joule’s Law – P=I x V 25. Amperes – measures current; Volts – measures electric potential (voltage); Ohms – measures resistance. 26 P = I 2 x R 27P = V 2 / R 28Electrons – Negative; Protons – Positive; Neutrons – Neutral 29A circuit consists of (at least) a power source, a conductor, and a resistor. 30Materials with “free electrons” are considered conductors (most metals); materials with “bound electrons” are considered insulators (wood).

8 31Electrons flow from the negative terminal of the power supply to the positive terminal of the power supply. 32 Voltage is the electric potential of an electric circuit; Current is the rate of flow of electrons through a conductor; Resistance is the resistance to electron current (resisting an electric current generally creates heat). 33Ohm’s Law – V = I x R; Joule’s Law – P = I x V 34A schematic is a diagram that represents the components of a system without using actual pictures. 35DC Power AC PowerResistorSwitch Conductor 36 Sketch schematics and write equations for 4 resistors in series and in parallel

9 37A smaller-diameter wire has more resistance than a larger- diameter wire because there is a wider “path” for electrons to flow in a larger-diameter wire. The wider the “path,” the lesser the resistance. 381,000 W = 1 kW. 1,000 V = 1 kV. 39Ohm – German mathematics teacher/professor, Ohm’s Law: V = I x R. Joule – English physicist, Joule’s Law: P = I x V. Faraday – English physicist and chemist; discovered that magnetic fields induce electric currents. 40 Conductors: Copper, Iron, Aluminum; Insulators: Glass, Wood, Cotton 41 The electromagnet on the electric motor was the bolt and the coil of wire wrapped around it.

10 42 43 An electromagnet is a coil of wire and some metallic artifact (like an iron nail or bolt) that creates a variable magnetic field that can be turned on and off. 441) An electromagnet can be turned on and off; 2) the strength and direction of the magnetic poles of an electromagnet can be controlled by altering the strength and direction of the electric current creating the magnetic field. 45The purpose of a switch is to provide a means to open and close (turn on and off) an electric circuit.

11 46. Fluid technology is the technology of using fluid, either gas (pneumatics) or liquid (hydraulic) to apply force or to transport. 47. Boyle’s Law: the pressure and volume of an ideal gas are inversely proportional when temperature is constant. 48. Pressure and volume are inversely proportional. This means that P a 1/V and V a 1/P (pressure is proportional to 1/V and volume is proportional to 1/P). 49. A pneumatic technology is a fluid technology using a gas. A hydraulic technology is a fluid technology using a liquid. 50. Aerodynamics deals with the motion of air and other gaseous fluids; air and gases are fluids and are used in fluid technology. 51 1) All fluid technologies use a fluid, either gaseous or liquid; 2) All fluid technologies contain a pressure difference that creates a net force.

12 52 Thermal Technology – the technology of producing, storing, controlling, transmitting and getting work from heat energy. Thermodynamics - the science dealing with internal energy, heat, and work Photon – a particle of light Conduction – the transfer of heat through a substance by collision of molecules. Convection – is the transfer of heat by movement of a fluid. Radiation – the transfer of energy by electromagnetic waves. 53. Furnace, Hot water heater, Toaster, Insulation, Heat exchanger, Refrigerator, Hot air balloon, Fan, Engine cooling system, Oven, Blow-dryer, Thermos, Heat shrink, Styrofoam, Radiator, Blanket, Winter jacket, Wool socks 54. The more powerful radiation heat is in the form of infrared light, which we cannot see with our natural eyes. Therefore, infrared photography allows us to “see” the heat given off by objects even if the material is not hot enough for there to be a color change.

13 55. Natural Convection: Fluid surrounding a heat source receives heat and rises (due to lower density) Surrounding cooler fluid moves in to replace it. Cooler fluid is heated, rises, and cycle continues. 2) Forced Convection: Fans or other means are used to propel a fluid. An convection current is induced. Car engine and A/C are examples 56. White, Blue, Yellow, Orange, Red 57. Solid, Fluid, No medium 58. Thermal energy flows from regions of high temperature to regions of lower temperature. 59. The driving force for heat transfer is a difference in temperature. 60. The more accurate way of saying an object is “cold” is saying that it lacks heat. 61 1) Conduction: the transfer of heat through a substance (typically a solid) by collision of molecules. 2) Convection: the transfer of heat by movement of a fluid. 3) Radiation: the transfer of heat by electromagnet waves

14 73.The technology of putting mechanical parts and materials together to create supports, containers, shelters, connectors, and functional shapes. 74.Tension structures: spider web, climbing rope. Compression structures: chair legs, book shelves 75. Father of modern science, Father of modern physics, First modern engineer. 76. 1) Inertia, 2) F = ma, 3) Action/Reaction. Structural technology based mainly on #3. 77. The earth is pushing up at you with 150 lbs. (or whatever else your weight may be). 78. Type, size, shape, and placement of material determines its strength. 79 Beams are horizontal structural members Posts are vertical structural members, Trusses are an assemblage of beams forming a rigid framework.

15 80. The goal of structural members is to be as light as possible without being too flexible or unstable. 81. Tacoma Narrows bridge (1940), Challenger Space Shuttle (1986), Columbia Space Shuttle (2003), Chernobyl Nuclear Reactor (1986), 2007 Missouri bridge collapse 82. Trial and Error. 83. Common Sense. 84 1) Compression: a pushing force; 2) Tension: a pulling force; 3) Torsion: a twisting force; 4) Shear: a sliding force. 85 Deflection is bending that results from both tension and compression acting on a structural member at the same time.


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