Presentation on theme: "Chapter1: principles of Design"— Presentation transcript:
1Chapter1: principles of Design Engineering Design and Problem Solving
2Introduction/Description The Intro-Mini Project will introduce the engineering design process through a problem solving scenario, as well as the concept of Coefficient of Restitution (COR), and sketching and technical drawing.You will work in project teams and present your data and solutions to the class.
3Chapter 1: Outline Engineering Careers History of Engineering and InnovationImportance of InnovationFuture Challenges of Innovation
4Objectives and Results To review scientific concepts of kinetic energy, potential energy, and energy transfer.To determine the coefficient of restitution (COR) for various sports balls.To understand elastic and inelastic collisions.To practice sketching and creating technical drawings of various sports balls using graphic tools.To apply the concept of engineering design to a problem scenario.To reinforce collaborative and communication skills.
5Objectives and Results, cont. Students will be able to explain the concept of engineering design.Apply engineering design concepts to a problem scenario.Practice sketching technical drawings and engineering notebooks.Reinforce collaborative and communication skills.
6Schedule of Assignments Class Period(s)Topic(s)ReadingAssignment1Provide information to complete the Mini Project finding the coefficient of restitution for various sports ballsVocabularyRubricsCoefficient of Restitution Internet article;Ball Bounce article#1-Individual; Complete reading and select teams2Collect data for Mini ProjectChapter#2-In teams of 2-3; Calculate the coefficient of restitution for various sports balls, sketching, and recording data collected3Create presentation of data#3-In teams of 2-3; Develop conclusions and create presentation of Mini Project4Share PowerPoint presentation with class#4-In teams of 2-3; Complete the communication & presentation of your data following the rubric given; complete the mini engineering notebook (Daily)
7Vocabulary Coefficient of Restitution Elastic Collision Energy TransferInelastic CollisionKinetic EnergyPotential EnergyCoefficient of Restitution (COR): a fractional value representing the ratio of velocities after and before an impact (sometimes to referred to as “bounciness”); an object with a COR of 1 collides elastically, while an object with a COR < 1 collides inelasticallyElastic Collision: an encounter between two bodies in which the total kinetic energy of the two bodies after the encounter is equal to their total kinetic energy before the encounter; elastic collisions occur only if there is no net conversion of kinetic energy into other formsEnergy Transfer: the transfer of energy from one body to anotherInelastic Collision: a collision in which kinetic energy is not conservedKinetic Energy: energy that a body possesses by virtue of being in motionPotential Energy: energy which an object has because of its position; it is called potential energy because it has the potential to be converted into other forms of energy, such as kinetic energy
8Team Building What is a team? “A team is a small group of people with complementary skills who are committed to a common purpose, performance goals, and approach for which they hold themselves mutually accountable.”Katzenbach, Jon R., and Smith, Douglas K., The wisdom of teams: creating the high- performance organization; Jon R. Katzenbach, Douglas K. Smith Harvard Business School Press, Boston, Mass.: 1993What is a team?
9What is Team Building?Creating a successful team can be a challenging task.Teams must rely on the process called team building.Team building integrates individual skills and resources into a unified effort.
10Team Building Actions Team building involves the following actions: Encouraging team members to examine how they currently work togetherPortraying ideal ways of collaboratingExploring the gaps and weaknesses they currently suffer fromEstablishing action plans for implementing more effective ways of cooperating
11What is a Team Leader?Team building is best aided by a team leader or a facilitator.A team leader or facilitator performs several tasks:Helps the group learn about itselfObserves team meetingsGives feedback and key observations to the team
12What Does a Team Leader Do? A team leader probes, questions, listens, watches for nonverbal cues, and stimulates problem solving.The intended results include a team that is open to new alternatives, who is aware of their resources, has the ability to think and act independently, and is willing to explore the consequences of their current or proposed actions.
13Benefits of Team Building There are several benefits for executing team building:Improves morale and leadership skillsClearly defines objectives and goalsImproves processes and proceduresImproves team productivityIdentifies a team's strengths and weaknessesImproves the team’s ability to problem solveWe need team building because it builds team morale and leadership, builds trust, reinforces appropriate behaviors of team members, and helps team members to become more flexible and adaptive to solving problems.
14Team Building Assignment In your team, discuss leadership roles and responsibilities of team members.Select roles for each team member.Write and agree to team contract.Have your teacher approve your team contract.Discuss implications of team building in the field of engineering.
15Energy Energy Transfer – moving energy from one body to another Kinetic Energy - energy that a body possesses by virtue of being in motionPotential Energy - energy which an object has because of its positionEnergy Transfer - moving energy from one body to anotherKinetic Energy - energy that a body possesses by virtue of being in motionPotential Energy - energy which an object has because of its position; it is called potential energy because it has the potential to be converted into other forms of energy, such as kinetic energyRoller Coaster Graphics: “The cars of a roller coaster reach their maximum kinetic energy when at the bottom of their path. When they start rising, the kinetic energy begins to be converted to gravitational potential energy. The sum of kinetic and potential energy in the system remains constant.”
16Loss of Energy Mechanical energy is the sum of the energy of motion: KE (Kinetic Energy) = ½ mv2GPE (Gravitational Potential Energy) = mpgwhere m = mass, v = velocity (speed), g = gravitational pull, and p = potential energy.The total energy in a system is conserved, but when a ball bounces, it loses mechanical energy because the collision between the ball and the surface is inelastic.The amount of energy that the ball loses will depend on the coefficient of restitution, a ration of its pre-collision velocity to its post-collision velocity.
17Coefficient of Restitution The coefficient of restitution (COR), or bounciness of an object, is a fractional value representing the ratio of velocities after and before an impact (vup/vdown).An object with a COR=1 collides elastically.< 1 collides inelastically.The coefficient of restitution (COR), or bounciness of an object, is a fractional value representing the ratio of velocities after and before an impact.COR = vup/vdownAn object with a CORequal to 1 collides elastically.less than 1 collides inelastically.Bouncing ball strobe graphic:
18Elastic and Inelastic Collision Elastic Collision - an encounter between two bodies in which the total kinetic energy of the two bodies after the encounter is equal to their total kinetic energy before the encounter.Inelastic Collision - a collision in which kinetic energy is not conserved
19Determining Coefficient of Restitution The amount of energy that the ball loses will depend on the coefficient of restitution (COR), a ratio of its pre- collision velocity (vup) to its post-collision velocity (vdown).Coefficients of Restitution YouTube videoCoefficients of Restitution YouTube video:
20Using the Velocity Formula In order to find velocity (v), use the height of the ball after it hits the ground (h) and put it in the following equation:v = √(2gh)where v = velocity, g = 9.8m/s2, and h = height when ball is dropped.Coefficient of Restitution = √(2gh)) / √(2gH) = √(h/H) where H is the initial height of the ball.
21Ball Bounce Article“The dynamics of a collision between a ball and another object can be determined in principle, from the individual conditions and the functional form of the force acting on the ball.” Ball Bounce ExperimentDynamics of BounceExperimental Techniques and ResultsComparison of Static and Dynamic Hysteresis CurvesBall VariationsEffects of Ball SpeedStudent Handout: Ball Bounce Handout“The dynamics of a collision between a ball and another object can be determined in principle, from the individual conditions and the functional form of the force acting on the ball.”Rod Cross, Am J. Phys, 67 (3), March 1999,Dynamics of BounceExperimental Techniques and ResultsComparison of Static and Dynamic Hysteresis CurvesBall VariationsEffects of Ball Speed
22Student ScenarioIt’s the beginning of the school year. Students are interested in joining an extracurricular sporting team. There are several female and male sporting teams to choose from at the high school.What are the sporting teams at your high school?Research and list the various types of extracurricular sporting teams available for both female and male students.Gather the types of balls used for each extracurricular sporting team.Driving QuestionsWhat is the coefficient of restitution (COR) of the various sporting balls?What are the female and male sporting teams at your high school?What are the types of sporting balls used by the female and male students?Why might different balls be used for different sports?
23Student Project Basics Individually and in teams, you willcalculate the coefficient of restitution (COR) for at least 5 sports balls,create sketches and diagrams in your engineering notebook for each ball,design a new type of ball for at least one sport,document the design process your team went through, andpresent your findings to the class.
24Step 1: Getting StartedDetermine the female and male sporting teams on campus.Gather the types of sports balls used by each female and male sporting team on campus and document them in your engineering notebooks.
25Step 2: Collecting Data Gather a meter stick, balance (to explore relationship between mass and energy for extension applications), andrandom measurement equipment (figure out what you really need to use), timers, graduated cylinders, balances, forces, scales, etc.
26Step 3: AnalysisSketch designs of the various sports balls on graph paper.Create technical drawings of the various sports balls using software graphic tools.Demonstrate teamwork and professionalism.Determine the height of the ball after it bounces.Determine the coefficient of restitution (COR) of the sports balls.
27Step 4: Engineering Design Considering your data and what you learned about the behavior of each ball, would any of the balls perform better in another sport? Explain.Design a new type of ball for at least one sport. There is not necessarily a right or wrong answer.Create a presentation about the coefficient of restitution of the various sports balls and the new type of ball you are proposing for at least one sport. Be sure to document your procedure, data collected, and conclusions drawn.Sketch design of the various sports balls on graph paper.Create technical drawings of the various sports balls using software graphic tools.Demonstrate teamwork and professionalism.Determine the speed of the sports balls right before it hits the ground and then right after it bounces.
28Step 5: PresentationPrepare a Microsoft PowerPoint team presentation of your work (rationale and results).Reflect on the concepts of energy and collisions.Explain what you have learned and why different balls might be used for different sports.Describe the new type of ball your team designed for at least one sport.In as much detail as possible, explain the steps of the process your team went through in order to come up with the new ball design.
29Conclusion/Questions to Consider Why is the coefficient of restitution of a ball so important in sports?What are the factors that determine the COR?What might happen if you tried to use the “wrong” ball for a sport?
30Credits ClipArt; http://www.clipart.com/en/ Images;Slide 19Coefficient of Restitution video; from YouTube user; Gaby Salguero