CK-12 Engineering: An Introduction for High School
Page 12
Explore
Students are given the problem of designing a method of cooking food using solar energy as a feasible alternative to collecting fire wood. Working in teams, they use the Internet and other sources to collect information to understand the design characteristics necessary for a solar cooker to be useful in a developing country. They organize and report this material to the class.
Then students work in teams to develop a design concept and document the concept with a detailed drawing. The idea here is that students will employ an ad hoc process that becomes the basis for discussion as they go through the Explain process.
Explain
The design process is explained to the students using the material in this chapter; the students are exposed to the steps of the design process. They compare and contrast the process they used in the explore activity with the design process covered by the teacher. They also complete the right column of their KWL chart.
Extend
Student teams go through a scaffolded design process to create and evaluate a prototype of a solar cooker. This process need not include all of the steps described in the Introduction to Engineering Design chapter, particularly for novice designers. As students work through each step in the design process, some scaffolding should be provided; for example, each team may report its work on each step to the class and receive formative feedback on their work before moving on to the next step. In addition, the way in which each step is performed may be tailored to the developmental levels of the students. Novice designers may be asked to concentrate on the outcome that should be produced, while more advanced designers may be asked to employ some or all of the tools identified it the Introduction to Engineering Design chapter.
The following gives information on some of the design process steps that could be required of the students.
Identify Criteria and Constraints
Students develop criteria and constraints for the problem of designing a solar cooker. Examples of possible constraints include
Cooker can be constructed from readily available materials.
Cooker can be constructed using simple hand tools.
Examples of possible criteria include
Maximum temperature reached inside the cooker when it is placed in direct sunlight.
Volume of food that can be placed in the cooker.
Time required to cook a typical meal.
A possible variation on this section of the activity would be to have student teams independently develop criteria and constraints, and then through class discussion create a single set of criteria and constraints for the whole class. This would allow different teams to evaluate their prototypes using a class-wide standard.
Generate Ideas
Students generate ideas for the design of their solar cooker. For novice designers, it may be sufficient to use an ad hoc process to come up with two different concepts. For more advanced students, the process and tools described in this chapter may be appropriate.
Examples of possible design concepts include
A cardboard box with a clear plastic wrap top.
A cardboard box with a clear plastic wrap top plus foil covered cardboard reflector is to direct more sunlight into the box.
A cardboard box painted black inside with a clear hard plastic top.
Select a Design
Students use their constraints and criteria to select a design concept to use in creating their prototype. Advanced students should use the tools and process described in this chapter.
Build a Prototype
Students create a prototype of their selected design concept.
Test the Prototype
Students test their prototype to verify that it meets the constraints and perform the experiments necessary to determine how their design performs relative to the criteria.
Evaluate
Student teams present their designs and their processes to the class. Each student team’s processes are evaluated according to the rubric in Table 3 by the teacher and by the other students in the class. This evaluation is the basis of formative feedback to each team.
To implement the learning cycle, students could use this feedback to revise their designs and build a second prototype. This would emphasize the iterative nature of the design process.
Rubric to evaluate the overall design process as well as the steps in the design process. Student Outcomes Strongly meets criteria Adequately meets criteria Minimally meets criteria Does not meet criteria
Recognize that design is a process. Gives detailed description of processes. Describe most steps of processes followed to design oven. Describe some steps of processes followed to design oven. Describes design without describing the design processes.
Quality of design process Evaluates quality of all steps and relates this to the quality of the resulting design. Evaluates quality of most steps and relates this to the quality of the resulting design. Evaluates quality of some steps and relates this to the quality of the resulting design. Does not evaluate the quality of any steps.
Apply each step: Criteria and constraints Identifies several criteria and constraints; criteria and constraints are properly formed. Identifies several criteria and constraints, most of which are properly formed. Identifies several criteria and constraints; some of which are properly formed. Does not identify several criteria and constraints; confuses criteria and constraints.
Apply each step: Generate ideas Decomposes the overall design problem, finds solutions to subproblems, and uses concept combination techniques. Uses one or two tools(brainstorming, problem decomposition, etc.) to develop several design concepts. Uses ad hoc processes to develop several design concepts. Only develops a single design concept.
Apply each step: Select a design Selects between design concepts using a formal tool with criteria and constraints. Uses a tool to select between concepts; selection reflects some criteria and constraints. Uses ad hoc processes to select between concepts; selection reflects some criteria and constraints. Does not use criteria and constraints to select between design concepts.
Apply each step:Prototype Tests the prototype to determine whether it meets all constraints and how it performs relative to all criteria. Tests the prototype to determine whether it meets most constraints and how it performs relative to most criteria. Tests the prototype to determine whether it meets some constraints and how it performs relative to some criteria. Test do not reflect criteria and constraints.
Solar Cooker Design Project Evaluation
The following exercise provides an assessment of students’ learning of the design process.
Theresa and Jack are designing a purification system for water that can be used in parts of the world where there is frequent flooding. They have a deadline and must work quickly because many parts of the developing world are suffering from severe flooding and people are getting sick drinking contaminated water. Jack feels that their first design is good and wants to build and ship the prototype to people in need. He does not want to waste time when lives are at stake. Theresa wants to look at several designs and then build and test a prototype. She thinks that they might even have to refine their prototype before it is ready for people to use. Jack argues that this process will take too much time. Use your knowledge of the design process to craft an argument that supports either Theresa or Jack.
Chapter 5: Connecting Science and Mathematics to Engineering
About This Chapter
Engineering is the application of the principles of mathematics and science to the creation or modification of components, systems, and processes (which are often referred to as a product or an artifact) for the benefit of society. Engineers use a series of logical steps (the engineering design process) to create such artifacts which represent a balance between quality, performance, and cost. This chapter explores and examines the role and connections of math and science to engineering and the need to succeed in the study of those subjects for a professional career in engineering.
After working through this chapter, you should be able to do the following:
Explain the goals and the nature of the fields of science, mathematics, and engineering and the differences between them.
Explain generally how the fields of math and science and engineering benefit from one another as well as need one another.
Explain what engineers in different disciplines do and the math and science they use.
Explain the role of science and math in each step of the engineering design process.
Describe the types of science and math that might be used by engineers in the different engineering disciplines along with an example for the design of a product or a process.
Case History: How Math, Science, and Engineering Led to the First Pocket Radio
Imagine that it is November 1, 1954 and Dwight “Ike” Eisenhower is president and Leo Durocher’s Brooklyn Giants have just swept the World Series from the Cleveland Indians. Willie Mays has become a World Series legend after making “The Catch” in center field over his head with his back to the infield. Today, you have also just purchased a Regency TR-1 (Figure 1), the world’s first “pocket” radio. It cost $49.95 (equivalent to $400 in 2007 dollars) with its four transistors, and you are now listening to Elvis Presley’s first hit, “That's All Right”. The radio is gray, weighs 12 ounces, and with a size of , you could slip it right into your pocket. This is a lot more convenient than the old vacuum tube portable radios which were bigger, bulkier, and heavier than the new transistor radio. One of these is an RCA 66BX, a six-tube portable radio that weighed 3 pounds and was in size. Where did this incredible piece of shrinking technology come from? We shall see.
Figure 5.1
A portable transistor radio. The worlds first transistor radio, the Regency TR-1 weighed 12 ounces with dimensions of
The basic scientific knowledge necessary to develop a transistor radio started from the time when, on December 14, 1900, German physicist Max Planck explained to the world how an atom’s electrons behaved with a new theory called quantum mechanics. Over the next 20 years a mathematical model was developed for this theory, including an important equation called Schrödinger’s equation. From there, it was these basic principles of science and mathematics directed toward their practical application in electrical devices that led three researchers at Bell Labs on a race. The race was to invent a solid-state device that would replace bulky, unreliable, and energy-consuming vacuum tubes used in consumer electronics (such as radios) at the time. So it was that, on October 16, 1947, physicists John Bardeen, Walter Brattain and William Shockley, applied the mathematics and science of quantum physics to semiconductors to invent the world’s first transistor. They had created a device that could amplify a weak electronic signal 18 times over a wide range of frequencies. For their efforts they received the Nobel Prize in 1956.
Now that this new device existed, how would it be used? Texas Instruments used special materials processing techniques to make very pure semiconductor material necessary for transistors and started manufacturing them by 1952. Using those transistors, which cost $2.50 each ($2.50 will buy 100 million transistors on an integrated circuit today), engineers at the Regency Division of IDEA (Industrial Development Engineering Associates) of Indianapolis, Indiana, used the engineering design process to design, develop, and fabricate the world's first pocket radio. The electrical engineers at Regency used their industrial experience and the knowledge from their education on physics, mathematics, engineering science and electrical engineering to design a small radio; 100,000 units were manufactured. The connections of science and math to engineering are clear. The understanding of a phenomenon of the natural world, quantum physics, and the mathematical modeling of the phenomenon promoted the insights on the electrical behavior of semiconducting materials. It was the three researchers at Bell Labs who were searching for a solution to the well-defined problem of poor electrical behavior of vacuum tubes that led the team to invent the transistor. It was a very practical device indeed, since materials engineers at Texas Instruments were able to produce transistors in quantity so that another team of electrical engineers at IDEA could design, develop, and manufacture that first pocket radio.
The above case history of the first transistor radio illustrates the interplay of math, science, and engineering that occur in commercialization of a new device that later thrilled the country. And it did not take long for society to realize the benefits of quantum mechanics, Schrödinger’s equation, and the invention of the transistor. You could see it on some playgrounds a year after the Regency TR-1 was first merchandized. A crowd gathered around kids that brought their dads’ pocket radios to listen to the World Series when the Brooklyn Dodgers beat the New Yankees in seven games. That miraculous little radio was a reflection of the “can do” spirit of the decade of the 1950s. Engineering could make science fiction reality. At the time cartoon detective character Dick Tracy had an imagined video-walkie-talkie-computer wrist watch, which he used to run down the city’s criminals. Part of it became a reality but now, a half century later, today’s high tech embodiment of Tracy’s watch, the iPhone, can do everything Tracy’s watch did and more. Next, let us consider the impact of technology in your own life from the exercise below.
Figure 5.2
An electric toothbrush and a microwave oven. The electric toothbrush was invented in 1939 but not popularized until the 1990s. The microwave oven was a spin-off of World War II radar technology and was invented in 1946.
Activity
How does technology affect you and your everyday life? Technology created by engineers affects everyone in their daily lives, usually in subtle understated ways. Try this exercise to explore the impact of technology with devices such as the electric toothbrush or the microwave, as shown in Figure 2.
Write down a short list of three or four electronic devices or gadgets that you use everyday.
Write a short description of how you use them, how they affect your life, and how your life would be affected if they had not yet been invented.
Take a guess at what kinds of engineers were involved in helping create one of the devices. Select one type of engineer and think about how she/he how might have used math and science in making the device?
What Is the Role of Science and Mathematics in Engineering?
This chapter has already introduced some ways in which science and math are connected to engineering. The chapter will continue to explore these connections in invention, innovation, education, careers, and design, as well as the impact on our daily lives. It is also becoming clear why it is critical to prepare for engineering education in college by taking and doing well in science and math courses throughout elementary, middle, and high school. In fact, the single best indicator of success in graduating with a college degree in engineering, science or math is taking courses in high school that include four years of math (at least through trigonometry) and three years of lab science. In the remainder of this chapter, we will now expand, articulate, detail, and exercise the engineering–math–science connection. The techniques of mathematics and the phenomena of science are like the brushes and colors on an artist’s palette. Just as an artist creates a new reality with his/her painting, so does an engineer create a new reality for how individuals live in a society. We have seen an example of this not only with the creation of the first pocket radio, but also how the reality of our daily lives have been impacted by other artifacts such as the cell phone and the computer. The next section will examine in greater detail the nature of the connection between math, science, and engineering.
What Is Engineering?
Engineering creates valued products such as the pocket radio. This is done by analyzing the nature of a problem or a need and then applying knowledge of math and science while completing the engineering design process to develop a solution to the design problem. A knowledge of science (e.g., chemistry, physics, and biology) helps the engineer understa
nd the constraints inherent in a problem and helps the engineer develop possible approaches for a solution. Math (e.g., algebra, geometry, calculus, computer computation) is used both as a tool to create mathematical models that describe physical phenomena and as a tool to evaluate the merit of different possible solutions.
The profession of engineering is more formally defined by ABET, an organization that accredits college engineering programs, as “Engineering design is the process of devising a system, component, or process to meet desired needs. It is a decision-making process (often iterative), in which the basic sciences, mathematics, and the engineering sciences are applied to convert resources optimally to meet these stated needs.” Within this definition, science and mathematics are described as an essential part of the entire engineering process. They do not act alone within this process. “Engineers apply the principles of science and math to develop economical solutions to technical problems. Their work is the link between perceived social needs and commercial application.” (US Department of Labor) The goals of math and of science in engineering differ from those within the field of mathematics (where the goal is to quantitatively represent functional relationships) or the field of science (where the goal is to understand the natural world). In engineering, math and science are tools used within the engineering design process. Using the design process to address a problem or an issue leads to the solution of the problem and a product which might be a component, a system, or a process that fulfills a need that will benefit society. All fields of engineering use the tools of both math and science throughout all steps of the engineering design process. Effective use of math and science are critical to creating a high-quality solution to a need and an associated product of the process.