What is 21st Century Secondary Engineering?

By Bradley Heilman

Increasingly in society, much of what surrounds us has been engineered. We wear clothing designed to wick moisture from the body, stretch, stay wrinkle free, and protect us from UV radiation and insects. We live in structurally sound buildings with optimized lighting, heating and cooling, smoke detection, and numerous other technologies. We use cellular phones that know the correct time in every zone, can download digital media, and run on a rechargeable battery for several days. But how does all this work?

Figure 1. The natural frequency of a glass bottle can be measured with a $2 sensor and a computer. The top graph shows the waveform of the natural frequency within the bottle. The bottom graph shows the frequencies present at resonance.

Relative to its importance, engineering is greatly underrepresented in elementary and secondary education. As a consequence, many high school students are unaware of engineering-related careers and unable to make the informed civic decisions demanded of citizens in a technological society.

In this era of teaching to standards, it is important to note that national standards have clearly defined the skills and knowledge expected of secondary students in engineering and technology. Engineering is treated extensively in the National Science Education Standards and the International Technology Education Society. The boldest statement about secondary engineering is found in the AAAS Benchmarks, in which two of the twelve describe engineering topics: Benchmark 3, "The Nature of Technology" and Benchmark 8, "The Designed World."

To illustrate the detail and specificity of these benchmarks, consider just one in the "Energy Sources and Use" sub-section of Benchmark 8 for middle grades: "Students should know that ... electrical energy can be produced from a variety of energy sources and can be transformed into almost any other form of energy. Moreover, electricity is used to distribute energy quickly and conveniently to distant locations." This example shows the close association between science and engineering and suggests that the 21st century curriculum should integrate engineering topics with science instruction. The following section describes how this can be done.

Projects in Science, Math, and Engineering

Easy access to information and computer technologies (ICT) can revolutionize secondary engineering education. Of course, ICT can be studied as an important engineering topic—students can learn about the computer, programming, interfacing, and networking. But just as importantly, ICT can facilitate learning all engineering topics, in the way that ICT supports major innovations in math and science education, as described throughout this newsletter.

The two uses of ICT are mutually reinforcing: students who learn about ICT technologies are also empowered to use these technologies to expand their math and science learning. And the ability to make one's own technologies gives students insights into otherwise "black boxes," expands the range of possible investigations, and reduces equipment costs.

Figure 2. A graph showing
temperature in a room
heated under thermostat
control. The fluctuations are
typical of a system with
feedback. This can be measured
with a student-built
temperature sensor (inset).

Student projects are the proven strategy for engineering education. This approach provides a hands-on learning experience, where students get a genuine opportunity to be inquisitive and come up with solutions. Projects are best undertaken in small teams with defined roles, much the way most science and engineering is done. The potential pitfall in the use of projects is that they can be too openended, and consume time and resources. To avoid getting mired in low-yield projects, the curriculum needs to focus on well-defined activities that provide guidance and have clear educational purposes. This can be done with highly interactive computer-based activities that provide motivation, opportunities for reflection, guidance, hints, and support for sharing reports.

The following two projects illustrate the power of projects and the role of ICT technologies.

Taking Measurements: Natural Frequency and Resonance

Did you know that the human stomach resonates at a frequency of 4-8 Hz (cycles per second), and that your head resonates around 20-30 Hz? Fortunately, the engineers designing cars are aware of this (or you might get car sick if the car's vibrations occurred at the same frequency as your head or stomach). The topic of natural frequency can be investigated using a two-dollar microphone connected to a computer, a glass bottle, and free software developed by the Concord Consortium called the Sound Grapher (see @Concord, Fall 2005). Figure 1 shows the natural frequency of the bottle, as depicted by the Sound Grapher. Using free tone generation software from the Web or installed on your computer, this activity teaches the fundamentals of resonance and tuning, and can be extended to investigate mechanical principles in construction, car and instrument design, and electrical principles in circuit or cell phone design.

Understanding Systems: The Classroom Thermostat

Is the air temperature in your classroom constant? Inside air temperatures are always changing as air is heated or cooled by objects within the classroom, air mixes from sources such as windows and doors, and other factors. Figure 2 shows a student-made fastresponse temperature sensor, which costs under $10 in parts. This sensor can quickly measure small changes in air temperature. The graph shows the fluctuations caused by a room air heating system. The air temperature gradually drops, the heating system turns on, the temperature rises, and the system turns off. Students can measure these changes, then build their own heating system using a temperature sensor and a switch-operated heating element or fan. This feedback loop is part of every heating and cooling system. Such feedback loops are all around us, from nightlights to the radiator fan in a car.

Core Concepts

The 21st century secondary engineering curriculum should be built around a carefully designed progression of projects such as these. The projects would increase in sophistication throughout the grade levels and be selected to focus on core engineering concepts:

• Hands-on design and construction of both mechanical and electrical systems. Students need to develop a range of technical skills and common construction sense. They should learn about materials, time and financial constraints, and flexibility and compromise in project planning and execution.
• Taking measurements and testing designs. Some measurements may be done with mechanical tools (e.g., a ruler), but often the best approach is to use sensors and computers. Thermisters, phototransistors, Hall effect probes, and other inexpensive sensors can interface to a computer with a general-purpose voltage input. This do-it-yourself approach greatly expands the range of applications of probeware while also introducing students to the rudiments of electronics and interfacing.
• Using mathematical models and simulations. Students can extend their understanding and investigate situations not easily explored through other means. Models also introduce students to a widely used engineering tool. Almost every large-scale engineering project is modeled prior to production, which helps determine feasibility, safety levels, and costs of construction and operation.
• Understanding engineering systems. Systems are collections of components that work together to achieve a result. A system can be compact—such as the components in a pair of pliers or a mechanical clock—or as complex and widespread as the phone system. Students aware of the bigger picture— the components, the interactions between components, and the overall goal—are equipped for innovating or managing better solutions.

Conclusion

Engineering and technology are continually advancing in our society. Such advances are a call for more attention to 21st century secondary engineering. They are also an indispensable enabler: as computer technologies become more prevalent, they can be leveraged to teach concepts of engineering in a meaningful, effective, project-based curriculum. This type of curriculum necessitates an understanding of science and math as building blocks for engineering.

The Concord Consortium is taking a first step at developing aspects of such a curriculum, funded by the NSF under an ITEST (Information Technology Experiences for Students and Teachers) grant. Teachers nationwide will help us use both computational models and real-time data acquisition to create activities appropriate for their classrooms and their communities. These activities will merge engineering with science and math, to the benefit of all STEM subjects, and more importantly, the benefit of the 21st century student.

Bradley Heilman (bheilman@concord.org) is a curriculum developer focused on the use of sensors and mathematical models.