1. CHAPTER 3 Problem Solving and Systems

2. PROBLEM SOLVING Humans have always been faced with problems to solve. They have always needed food, clothing, shelter and healthcare. These needs are met through technology. People solve their problems using available resources and knowledge.

3. HEADACHES  Have been a problem for a long time.  People used to drill hoes in a person’s skull!  This was supposed to let evil spirits escape. People did not know enough about headaches to solve this problem.

4. EARLY HUMANS…  Solved problems of food and shelter by using the materials around them.  Caves were used as homes.  People gathered roots, fruit, and seeds of plants to eat, and made tools to hunt animals for meat.

5. TODAY…  Problems are also those of human needs and wants, but there are many more problems and they are more complex than ever before. Some of these problems involve society and the environment, such as: How can we dispose of wastes without harming the environment? How can we produce enough energy to meet our increasing needs? How can we assure a continuing supply of clean, safe water?

6. GOOD DESIGN IN PROBLEM SOLVING  Solving a problem is rarely quick and easy.  We must understand exactly what is needed to solve the problem.  We must make our solution as low-cost and easy to use as possible.  These solutions must be compared so that the best one is chosen.  Then, the best ideas are further refined and improved. Good solutions to problems are those that work well, are inexpensive, and cause little or no harm to the environment and people.

7. EXAMPLES OF WELL DESIGNED TECHNOLOGICAL SOLUTIONS  Engineers, designers, and scientists solve a huge number of different technological problems. These can range from redesigning a stereo to creating new life forms like a plant that repels insects. Here arte some well-designed technological solutions:

8. THE TECHNOLOGICAL METHOD OF PROBLEM SOLVING  Problem solving is faster and easier, and results are better, if people follow a procedure. The 7 steps of problem solving are: 1. Describe the problem as clearly & fully as you can. 2. Describe the results you want. 3. Gather information 4. Think of alternative solutions. 5. Choose the best solution. 6. Implement the solution you have chosen. 7. Evaluate the solution and make necessary changes.

9. STEP 1: DESCRIBE THE PROBLEM CLEARLY AND FULLY  To solve a problem, we must first understand it. What has caused the problem? Here is an example of a clearly stated problem: People with arthritis in their fingers have a hard time gripping small objects. They need an easy way to carry out such tasks as unlocking a door. Once we know what a problem is, we can decide what to do about it.

10. RUBBER-BAND-POWERED VEHICLE  This may be a problem that might be presented in class.  This vehicle must be able to carry a raw egg safely over a distance of 50 feet on a smooth, level surface. We want our vehicle to travel faster than other competing vehicles.  In this case, the problem is to win a school competition by constructing an egg carrying device. To more clearly define the problem, however, we must consider it very carefully.

11. RUBBER-BAND-POWERED VEHICLE CONT’D  We must recognize that winning the competition means: 1. We must design and construct a device powered by rubber bands. 2. The device must carry an egg without breaking it. 3. The device must be faster than any other student’s device.

12. STEP 2: DESCRIBE THE RESULTS YOU WANT  We may have several goals in mind for the egg transport problem. Perhaps we want: To have fun To improve our technical skills To get a good grade To impress our friends Major goal  to build a device that will win the competition

13. DESIGN CRITERIA  Our goals should take into account any special requirements imposed by the problem. The list of specification must include all the requirements of the problem. These requirements are called design criteria.  If we were building a house, our design criteria would include the kinds of rooms, number for stories, and whether the house will have a basement or an attic.

14. DESIGN CRITERIA FOR EGG TRANSPORT PROBLEM  1. The vehicle must carry a medium-size raw egg without breaking it.  2. The vehicle must be painted attractively.  3. The vehicle must have an identification number.  4. The vehicle must travel faster than any other competing vehicle.  Can you think of the other design criteria that was mentioned?

15. LIMITATIONS  Problems generally have limitations.  The specifications should include these limitations. 1. The vehicle must cost no more than two dollars. 2. The vehicle must weigh no more than 1 pound. 3. The vehicle must be able to fit into a 12” x 6” x 4” container. 4. The vehicle must be powered by no more than four #6 rubber bands.

16. STEP 3: GATHER INFORMATION  This information gathering is called research.  Some companies and government agencies constantly perform basic research into the nature of different materials and processes. They don’t expect to produce any products immediately from what they learn, but they save the results and hope that the new knowledge will be useful at a later time.  Companies often do market research to determine if customers will like a new product. Companies may ask potential buyers to fill out a questionnaire to find out what they like or don’t like.

17. STEP 4: THINK OF ALTERNATIVE SOLUTIONS  There is almost always more than one solution to every problem.  We can suggest several ideas., each one of which might do the job. These different ideas for solutions are called alternatives.  One way to develop alternative solutions is to use our past experience.

18. BRAINSTORMING  Another way of coming up with ideas.  During brainstorming, each person in a group can suggest ideas.  One person writes all the ideas down; no one is allowed to laugh at or criticize any idea, no matter how foolish or unusual it might seem.

19. TRIAL AND ERROR  Another way to develop alternatives.  This is the way most people do jigsaw puzzles.

20. INSIGHT  A fourth way to develop alternatives.  Have you ever had an idea just pop into your head?  These sudden ideas are usually followed by the “Aha!” response.  Insight comes from being thorough in researching the problem, and from being creative in thinking about the problem from many different angles.

21. ACCIDENT  Still, another way to come up with solutions is by accident!  Some of the most important discoveries, like penicillin, occur when the inventor goes as far as possible and still doesn’t solve the problem.  A chance happening then provides the answer.

22. STEP 5: CHOOSE THE BEST SOLUTION  Once you have developed your list of possible alternatives, you need to select the best one.  Each alternative must be examined to see if it meets the design criteria and constraints that were defined in Step 2. Usually you can throw away the alternatives that don’t meet the criteria or constraints.  You may need to do further research on each alternative.

23. OPTIMIZATION P. 56  Sometimes, the testing will suggest that if we change on alternative slightly or combine two or more alternatives, we will wind up with a better solution.  The process of changing or combining alternatives to improve them is called optimization.  By optimizing the alternatives, we can get the best possible solution to the problem.

24. STEP 6: IMPLEMENT THE SOLUTION  Once we choose the best solution, we can begin to put it in place.  We are ready to try the solution under actual conditions.  Implementation means actually building or creating the proposed solution.  Most often a prototype or model of the solution is made.  This is particularly important if the proposed solution is very large and costly, or if many of the final products must be made, or if the proposed solution presents risks to people or the environment.

25. STEP 7: EVALUATE THE SOLUTION AND MAKE NECESSARY CHANGES  We must study the solution and test is to see how well if satisfies the requirements described in step two.  Observing (monitoring) the results of the test may suggest how we can improve the design or construction of the solution.  The feeedback we get allows us to compare our actual results with the desired results.

26. SOLVING REAL-WORLD PROBLEMS  Social and Environmental Concerns  Politics  Risk/Benefit Trade-Offs  Need for Continued Monitoring  Values

27. SYSTEMS  A system is a means of getting a desired result.  A technological system does this through technology.  For example, an automobile is a technological system for traveling from one place to another.  A radio lets us listen to music or news.  A computer lets us do calculations quickly.  A system can be huge, such as a space shuttle. Or it can be small, like a pocket calculator.

28. TECHNOLOGICAL SYSTEMS ARE ALL ALIKE IN ONE WAY…  Each has: Inputs A process Outputs

29. THE BASIC SYSTEM MODEL  All systems include inputs, a process, and outputs.  Feedback is added to provide a better way of controlling the system.  The basic system model can be used to describe any technological system.  A system diagram can be drawn to show how these parts work together in a system…..

31. INPUTS  The input is the command we give a system.  It is also the desired result.  When we turn on a t.v., we are giving it a command. That command is: “Give us picture and sound.”

32. THE PROCESS  The process is the action part of a system. It combines the resources and produces results.  In an automobile, the process involves both the car and the driver. The seven technological resources are used in the process. Energy is stored in the gasoline. The machine is the car. People (the driver), information, time, materials, and capital work together to make the car go 30 miles an hour.

33. OUTPUTS  The output is what is produced. It’s the actual result.  We hope that the output matches the command input.  That is, we hope that the car will go 30 miles an hour when we step on the gas.  Most systems have more than one output.

34. FEEDBACK  How does the driver know when the car is going 30 miles an hour?  The driver checks the speedometer. The speedometer gives the driver feedback.  Feedback is information about the output that can be used to change it.  When the car’s speed reaches 30 miles an hour, the driver lets up on the gas.

35. MONITOR  The speedometer is a monitor.  A monitor gives feedback about output. It lets us compare the actual result to the result we want.  We can control the system, if needed, to get the output we want.  Systems with feedback are sometimes called control systems or feedback control systems.

36. CONTROL SYSTEM  A control system is being used to help you learn.  Your teacher uses homework and tests as monitors to see how well you are learning.  Your teacher grades and returns assignments  both of you use this feedback to find out where you are doing well and where you need more work or perhaps some help.

37. LOOP SYSTEMS  Systems that have feedback are called closed-loop systems. Feedback “closes” the loop from input to output.  Some systems don’t use feedback – these are called open-loop systems. A person who wears a blindfold while trying to draw a picture of a dog is an example of an open-loop system.  Without feedback, the person cannot compare the output to the input. When the blindfold is removed, the person can draw the picture more accurately. Now we have a closed-loop system.

38. MULTIPLE OUTPUTS  A system may produce several outputs. They can be 4 types: desirable, undesirable, expected, or unexpected.

39. SUBSYSTEMS  Systems are often made up of many smaller systems called subsystems.  When you are trying to understand a large system, you might find it helpful to break it into subsystems. You can study each of them separately.  Suppose you want to look at a transportation system that carries goods by truck from L.A. to New York City.

40.  You could break down the large system into smaller ones.  Some of the subsystems would be the vehicle system, the management system, and the communication system.  Each of these could be broken down further into more subsystems. You would want to create a subsystem tree.  See figure on page 70.

41. IN YOUR NOTEBOOK, ANSWER THE FOLLOWING ITEMS  1. What are the 7 problem-solving steps listed in this PowerPoint?  2. Give an example of how a person’s values might affect his or her decision about the kind of car to buy.  3. Name some subsystems that make up a large railroad system.