Technological Design © 2013 International Technology and Engineering Educators Association STEM  Center for Teaching and Learning™ Technological Design.

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  • Technological Design 2013 International Technology and Engineering Educators Association STEMCenter for Teaching and Learning Technological Design

    STS-118 Design ChallengeLunar Plant Growth ChamberTeacher Resource 3.2

  • STS-118 Unit: Big IdeaThe Engineering Design Process is a comprehensive, valuable tool that can be used to provide solutions to complex challenges on Earth and beyond. 2013 International Technology and Engineering Educators Association STEMCenter for Teaching and Learning Technological Design

    2013 International Technology and Engineering Educators Association STEMCenter for Teaching and Learning Technological Design

  • Lesson 3: Big IdeaThe design of technological devices requires the consideration of limitations, trade-offs, and many iterations before a final design can be selected. 2013 International Technology and Engineering Educators Association STEMCenter for Teaching and Learning Technological Design

    2013 International Technology and Engineering Educators Association STEMCenter for Teaching and Learning Technological Design

  • Identify Criteria and ConstraintsHelps to specify subsystemsAffects final design and developmentSubsystems include:Water and nutrientsAir circulationHeating and coolingLightingRadiation protection 2013 International Technology and Engineering Educators Association STEMCenter for Teaching and Learning Technological Design

    2013 International Technology and Engineering Educators Association STEMCenter for Teaching and Learning Technological Design

  • Active SubsystemsAre mechanical/electrical devices needed?PumpsFansLightsHeatersRecorders 2013 International Technology and Engineering Educators Association STEMCenter for Teaching and Learning Technological Design

    2013 International Technology and Engineering Educators Association STEMCenter for Teaching and Learning Technological Design

  • Energy SourcesPower needed for active subsystemsBatteriesPhotovoltaic cellsRadioisotopic thermoelectric generatorsFuel cells 2013 International Technology and Engineering Educators Association STEMCenter for Teaching and Learning Technological Design

    2013 International Technology and Engineering Educators Association STEMCenter for Teaching and Learning Technological Design

  • ControlsFeedback devicesSensorsTimersBrainsMicroprocessorsSwitchesExample: window fan with thermostat 2013 International Technology and Engineering Educators Association STEMCenter for Teaching and Learning Technological Design

    2013 International Technology and Engineering Educators Association STEMCenter for Teaching and Learning Technological Design

  • Passive SubsystemsFeedback devices not requiredExample, air moving by convection currents in a gravity environment 2013 International Technology and Engineering Educators Association STEMCenter for Teaching and Learning Technological Design

    2013 International Technology and Engineering Educators Association STEMCenter for Teaching and Learning Technological Design

  • OptimizationOngoing process of designingDependent on criteria and constraintsMay require subsystem redesignModels and prototypes allow testing for quality and efficiency 2013 International Technology and Engineering Educators Association STEMCenter for Teaching and Learning Technological Design

    2013 International Technology and Engineering Educators Association STEMCenter for Teaching and Learning Technological Design

  • System StabilityInfluenced by all components in the systemComplex systems have many layers of controls and feedback loopsResults in more ways things can go wrongComponents detect, back up, bypass, compensate for minor failuresExample: Three fuel sensors in the space shuttle external tank 2013 International Technology and Engineering Educators Association STEMCenter for Teaching and Learning Technological Design

    2013 International Technology and Engineering Educators Association STEMCenter for Teaching and Learning Technological Design

    International Technology Education AssocSlide #*12/01/2009STEMCenter for Teaching & Learning Engineering byDesignThe Big Idea:The Big Idea for this STS-118 Design Challenge Unit is:The Engineering Design Process is a comprehensive, valuable tool that can be used to provide solutions to complex challenges on Earth and beyond. This process can be used no matter what the problem is that must be solved.

    International Technology Education AssocSlide #*12/01/2009STEMCenter for Teaching & Learning Engineering byDesignDesigning solutions to technological problems is an iterative process. Good solutions slowly evolve into great solutions. This requires the designer to consider limitations and trade-offs before a final solution can be selected.

    International Technology Education AssocSlide #*12/01/2009STEMCenter for Teaching & Learning Engineering byDesignIdentification of criteria and constraints helps to specify which subsystems will be required in the design. As an example, an extremely moist environment may not require a subsystem to provide water but may require a way of removing excess moisture.

    International Technology Education AssocSlide #*12/01/2009STEMCenter for Teaching & Learning Engineering byDesignSubsystems are active if they require electrical energy to move air and water or provide energy for lights and other mechanical/electrical devices to function. International Technology Education AssocSlide #*12/01/2009STEMCenter for Teaching & Learning Engineering byDesignEnergy sources for active subsystems include batteries (chemical source), photovoltaic cells (solar/radiant), radioisotopic thermoelectric generators (RTGs) (nuclear), and fuel cells (chemical).

    International Technology Education AssocSlide #*12/01/2009STEMCenter for Teaching & Learning Engineering byDesignSubsystem controls require feedback (sensors and timers), a controller (small computer or microprocessor), and switching mechanisms (electrical or mechanical). A familiar example is a window fan with a thermostat. As the room temperature gets warmer, a thermostat senses this, and when the temperature is higher than the predetermined setting (set on a microprocessor chip), a switch is turned on that sends electrical energy to the fan. The fan turns on and begins to move cooler air.

    International Technology Education AssocSlide #*12/01/2009STEMCenter for Teaching & Learning Engineering byDesignSubsystems are passive if they do not require feedback devices. A passive solar collector will absorb heat and store it in a large mass that will then dissipate that heat later when the source is no longer available and the temperature around the mass begins to cool. International Technology Education AssocSlide #*12/01/2009STEMCenter for Teaching & Learning Engineering byDesignIn design, optimization means the designer is using the best materials that meet the criteria and constraints of the problem to solve. In other words, the material may not be the strongest, but is strong enough to meet the specified needs and economical enough to be a desirable solution to the problem. International Technology Education AssocSlide #*12/01/2009STEMCenter for Teaching & Learning Engineering byDesignSometimes critical systems have backup systems that are constantly checking on each other. An example would be the three fuel sensors in the external tank of the space shuttle system. If one sensor provides a different reading than the other two, then it can be determined that the sensor is faulty and the system is functioning as designed. International Technology Education AssocSlide #*12/01/2009STEMCenter for Teaching & Learning Engineering byDesign

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