In 1995, 50% of public classrooms in the United States had Internet access; in 1996, 65%; in 1997, 78%, in 1998, 89%. 95% of public schools in the United States are projected to have Internet access by 2000 (National Center for Education Statistics, 1998). President Clinton’s Technology Literacy Challenge has declared initiatives to connect every public classroom in the U.S. This presents a perfect opportunity to reach millions of children and teach them in an innovative, interactive way. The World Wide Web (web) has the chance to be an ally of education. The web provides a medium to teach things not found in textbooks and for communicating with other students outside a single classroom.

There is a call by the American Association for the Advancement of Science (AAAS) and the National Research Council (NRC) that science be "taught in a way that is authentic and engages students in inquiry and collaboration around real-life problems to help students build a rich understanding of science" (Soloway, 1996). The introduction of engineering into Kindergarten through 12^th grade (K-12) classrooms is an answer to this call. Engineering problems are a complex combination of technical math and science applications and societal and ecological impacts; engineering is interdisciplinary by nature. A student sees practical applications of math and science in engineering, which provides motivation for learning. Engineering problems are best solved through critical thinking and deductive reasoning, creative iterative design, and teamwork. Engineering problems require skills like logical thinking and social consideration. Such skills should be taught before students get to college to help children learn science the way the AAAS and the NRC have suggested. Engineering is the authentic application of science and fosters inquiry and collaboration. Perhaps the integration of engineering into K-12 classes will lead a student to a future profession in engineering; more importantly, it will present life skills that apply to all professions and engage students in practical applications of math and science.

This thesis examines the delivery of engineering education to K-12 classrooms through the Internet, the integration of the Technology Literacy Challenge and the AAAS/NRC challenge. Students in K-12 and their teachers are thus the intended audience of the web site. This project studies the challenges of content, design, and evaluation of a web site to teach children about fracture mechanics in dams and the societal impacts. This discussion focuses on the use the World Wide Web as more than a tool or game in the classroom, rather, as a medium of education and communication.

The first chapter provides background information on the National Science Foundation (NSF) project within which this thesis project is embedded and an overview of the objectives of a web site called Cracking Dams. The objectives of the Cracking Dams module are to generally introduce each of the following to K-12: engineering skills, civil and environmental engineering topics, when and how to use simulation in engineering, and the social and ecological impacts of engineering. Each of these objectives brings more to K-12 students than would be found in a traditional classroom textbook; each is discussed below.

Chapter Two provides background and a literature review on the use of interactive multimedia and the web to teach K-12 students. Chapter Three discusses the introduction of engineering to K-12 classes and the motivation for the contents of the Cracking Dams module. Chapter Four describes the design of the module, a discussion of each component, and the design of WebQuests for use with the module. Chapter Five discusses testing and evaluations of the module and its integration into K-12 classrooms. Chapter Six provides summary, conclusions, and future work.

The SimScience web site and CD-ROM have been created as part of a National Science Foundation alliance between Syracuse and Cornell Universities. This project began in 1995 and is fast approaching its conclusion in September of 1999; the materials produced are available on the web at https://sethna.lassp.cornell.edu/SimScience. The SimScience web site, also available on CD-ROM, is intended to help K-12 students learn about areas of science and engineering that use computer simulations. Researchers from the Physics Department and the Mechanical and Aerospace Engineering Department at Syracuse University and the Physics and Civil and Environmental Engineering Departments at Cornell University are working on four modules of SimScience. Each SimScience module introduces an area of science or engineering, discusses the computer simulations used for research in that area, and demonstrates or has the user perform a simulation. The four modules of SimScience are Membranes (Physics, Syracuse U.), Fluid Flow (Mechanical and Aerospace Engineering, Syracuse U.), Cracking Dams (Civil and Environmental Engineering, Cornell U.), and Crackling Noise (Physics, Cornell U.).

The Cracking Dams module of SimScience is the subject of this thesis project. This module deals with fracture mechanics and concrete dams, specifically. More completely, it teaches engineering skills, civil and environmental engineering topics, how and when to use simulation in engineering, and the societal and ecological impact of engineering. These skills and topics are untraditional for K-12 students but the fundamentals can be applied to other subjects.

Engineering typically has been a post-secondary degree and the specific disciplines of engineering (Civil, Mechanical, Chemical) will likely remain as college-level topics. But there has been a trend of late to bring some of the basics of engineering to K-12. Skills like teamwork, iterative design, and problem solving have been introduced in K-12 classes with positive results (Muller et al, 1995; Wilson et al, 1995; Crawford et al, 1994). Not only is K-12 a good time to start learning these skills, but it is the time. Engineering skills and topics should be available in the K-12 curricula such that students learn the skills and topics before college. These skills are required in a variety of college classes and professional situations and thus should be learned at some point. Teaching these skills in K-12 would make the transition to these situations easier. Also, these skills are interactive by nature, which makes the web an optimal medium through which to learn.

Teamwork and collaborative design are a hallmark of not only engineering but also many professions presently, such as Information Technology Consulting or Human-Computer Interaction Design; thus it is logical that teamwork should be taught in school. Collaboration is not something that can be taught in and of itself, though; it is more effectively taught as a means to an end (Guzdial and Carlson, 1995). Thus collaborative learning requires something on which the students can collaborate, such as an engineering problem. The introduction of engineering into K-12 provides an opportunity for students to collaborate on interdisciplinary problems that show them real-world applications of math and science. On the web, collaborative work is facilitated by WebQuests, which are lesson plans that are based on the Internet. Collaboration between classrooms across the world can take place more easily due to web technology such as chat rooms and electronic bulletin boards.

Iterative design implies a cycle of design and evaluation, again, applicable not only to engineering but other disciplines as well. User interface design of a web site or computer software, for example, requires the input of future users during the design process to achieve a usable design; this usually leads to a cycle of design, evaluation, and redesign. Similarly, in engineering, the best designs are scrutinized and then improved upon or revised. For example, a fracture on the upstream side of a dam (where the reservoir is) grows one foot when crack growth is first simulated on a computer. The engineer asks, "But will the crack grow more if water enters?" The second computer simulation takes water pressure in the crack into account; the engineer realizes that the water pressure does increase the crack growth and thus water pressure must be an important parameter to include in his or her study. As seen in this example, iterations on designs demand interaction between the person and the simulation; often there is interaction between people as well. Iterative design produces a more usable and efficient product than design that is singular or never revised. In the end, the design of engineering simulations requires creative critical thinking and communication. The web provides a medium for K-12 students to experience engineering simulation and practice their critical thinking and communication skills.

The final engineering skill to be addressed is the notion of problem solving, which includes critical thinking, deductive reasoning, and decision-making skills. Critical thinking and deductive reasoning go hand in hand. Students need to learn how examine a question or solve a problem step by step. If each problem is unique, as it is in engineering, a simple formula or method cannot be memorized for use each time. Students need to learn how to develop intuition, how to foster ingenuity, how to break a problem down into solvable pieces, and how to look at each piece analytically to solve it. If such skills are cultivated at an early age, students will realize that there are usually many ways to solve a problem.

In the beginning of a child’s education, he or she is taught that the way to get two is to add one and one. This is memorized. Later, he or she learns there are many ways to get two: 5 – 3; 8 / 4; 0 + 2. There is more than one way to solve the problem. Building on experience, children can learn that there are many ways to solve a problem. With the realization that multiple solutions are possible comes the decision of which solution is the most appropriate. This decision-making process fosters competence in the abilities to evaluate a situation and deliberate between solutions. For example, one dam could be built to store an enormous quantity of water for drinking and irrigation but it will cause the displacement of hundreds of thousands of people; but if two dams were built instead, they might store less water displace fewer people. There is certainly more than one design that will accomplish the goal of water storage; but what are the impacts and consequences of each design? How does one choose? Like teamwork, decision-making is not necessarily a skill best taught in and of itself; but learning how to make decisions in different situations by conceptually and mathematically comparing and evaluating the advantages and disadvantages can teach this skill to K-12 students. Decision-making is a life skill and children will benefit from being taught this skill as early as possible.

Success in problem solving requires communication, availability of information and resources, and the creativity and intuition to break the problem down and solve it. Communication and collaboration for problem solving can be within the classroom or between classrooms using the Internet’s bulletin boards and chat rooms. The Internet also provides a wealth of resources and information if the sources are reliable. An educational web framework can provide the scaffolding needed by K-12 students as they learn to solve complex problems. The WebQuest, one such framework, basically provides a lesson plan based on the use of the web.

Cracking Dams introduces children to civil and environmental engineering. Civil and environmental engineering is broken into three general areas: civil infrastructure; environmental engineering; and systems engineering and information technology. Cracking Dams includes all three areas with its discussion of the design and construction of dams, the fracture mechanics of concrete infrastructures, and the decision systems required for evaluating the different aspects of the engineering. This overview gives the student a well-rounded understanding of how interdisciplinary civil and environmental engineering can be. Environmental and infrastructure engineering are fundamentally interconnected, which makes them ideal subjects for hyperlinking on the web. Decision making systems and information technology are required for evaluation and simulation, tying it to environmental and infrastructure engineering. Fracture mechanics is often applied in the study of civil engineering structures, which make fracture mechanics an important aspect of civil and environmental engineering.

Environmental engineering includes management of water resources as well as fluid mechanics, hydrology, and hydraulic engineering; dam design involves all these aspects of environmental engineering. Dams are a vehicle of water management, whether the water is for drinking supply, power, or irrigation, so it can be argued that dams fall under water systems engineering. Hydrology must be studied in order to know the maximum probable flood for the design of a dam. Therefore, the technicalities of how the dam resists the force of the water or prevents flooding could be classified under hydraulic engineering, which deals with the movement of water.

A dam is only as good as the foundation upon which it sits. A structure that is fundamentally dependent on its foundation, a dam requires consideration in both structural and geotechnical engineering, the two major subdivisions of infrastructure engineering. Structural engineering deals with the design and analysis of civil structures traditionally made of steel and concrete, such as bridges, buildings, and dams. Geotechnical engineering focuses on soil, rock, and man-made materials both as foundation and structural materials. These considerations of dams place it in the infrastructure division. Thus dams have important aspects in both the environmental and infrastructure areas of civil and environmental engineering.

Fracture mechanics, the study of how a crack initiates and propagates, is an approach to the analysis of the structures and one way to determine the life or death of a structure. The strength approach analyzes the strength of the uncracked state of a structure and discounts the strength contribution of cracked sections. Unlike the strength approach, fracture mechanics does well to analyze structures even after they have cracked. Although the previous statement seems obvious, this is an important advantage for the application of fracture mechanics of concrete, which is often subject to cracking. Analytically, fracture mechanics gives a more complete picture of the behavior of large concrete structures like dams by more accurately modeling cracking.

Experimentally, it is usually unreasonable to physically simulate crack growth in large concrete dams; as a result, the study of dam fracture is dominated by computer simulation.

The Cornell Fracture Group has written and developed a robust program called FRANC2D that analyzes crack growth. This program is available for download for free. The Cracking Dams web site makes this cutting edge technology available and understandable for children through the interface of a Java™ applet on the web. A Java applet is an interactive application that is embeddable in webpages.

As noted above, sometimes it is not feasible to do experiments with life-size structures; these are the times when engineering computer simulations, the third learning objective of Cracking Dams, become important. Actually constructing a civil structure to learn about crack growth, load capacity, or stability is usually too dangerous, too expensive, or too time consuming. Computer technology and many brilliant people have made the simulation of earthquake loading, crack growth, and many other problems possible. Cracking Dams makes the computer simulation of crack growth possible for children through the Internet, is the first such application of its kind. The capabilities of the web have been expanded to include even the technological endeavors of engineers.

Computer simulations can save time, money, and lives in the long run, but only if the engineer understands the input and output of the simulation. First, a computer model of the structure must be assembled. This will require research on the structure, precedents, the state-of-the art, loading scenarios, and boundary conditions. Simplifications must be made, a two-dimensional analysis instead of three-dimensional, for example; attempts to include every last detail in a simulation may make it as costly as building the real thing. But there are certain details that may be crucial to the analysis; this is where sensitivity analysis and/or iterative design are imperative. Next, the output or results are only as good as the input. Once a simulation has been performed, a capable engineer knows how to read the results and has an idea of the range in which the results should fall (learned through research, theory, or data gathered from monitoring an actual structure, perhaps). In this way, the engineer can determine if a mistake was made in the input or during the simulation. Once reasonable results are obtained, the engineer must know how to interpret and draw conclusions from them.

Although this account of a computer simulation may have sounded technical, it bears a striking resemblance to reasoning learned in elementary school. In math, children learn both how to estimate and how to use a calculator. The child knows the answer the calculator returns is only as good as the information the child put into the calculator. He or she also knows what to expect by using estimation. Reading teaches children how to make inferences and draw conclusions. Students must learn to apply these skills to other subjects.

A dam is a societal structure: it affects people from the inception of the dam, to the services it provides, to its impact on the environment, to its potential catastrophic failure. Thus engineers must exercise ethics in the planning and design, construction, and maintenance of the dam; this is the final learning objective of Cracking Dams.

A new dam has both psychological effects and physical effects on society. Civil structures may be perceived as beautiful, ugly, frightening, or any number of other adjectives. Dams are viewed differently by different people. John Eastwood designed very thin, elegant, functional multiple arch dams, but not all engineers perceived them that way (Jackson, 1996). These designs were often rejected because professional and public perception regarded them as too thin to actually hold back millions of gallons of water.

Construction of a dam requires nature and society to change; there are physical effects on the environment and society from dam construction. Construction of a dam requires people and animals to make way for the coming reservoir; it will inundate a large area of land that once was dry. This may result in moving people or entire towns or villages, which costs a great deal of money. The Three Gorges Dam in China will displace over a million people by its completion, scheduled for 2009. Trees and wildlife habitat will be under water. Cultural and historical artifacts may be lost in the flooding of the land by the dam. An estimated 8000 archaeological sites will be inundated by the Three Gorges Dam reservoir (Zich, 1997).

On the other hand, things may change for the better. A dam may be creating the reservoir that provides the water supply for a county. A dam may be creating "green" hydroelectric power for a city. A dam may enable water transportation, control flooding, or allow irrigation. Dams are everywhere; there are approximately 75,000 dams in the National Inventory of Dams in the United States and over 25,000 "large" dams in the world, as reported by the International Commission on Large Dams (large has several definitions, including dams that are over 50 feet high).

Thus, with the advantages come the disadvantages of a dam. Dams impact the environment, which in turn impacts society. Existing dams in the U.S. are very controversial structures because they disrupt the ecosystem, such as endangering numerous species of fish. Some perceive dams as ruining perfect natural landscapes, which goes back to a negative physical perception of dams.

In addition to the passive damage they cause, dams can actively damage and destroy people and property in catastrophic failures. Such failures are being avoided by an increase in attention to dam safety. One issue in dam safety is the consideration of cracking in the structure. Concrete dams are very powerful structures by nature of the services they supply and the impact they have. As a result of dams’ sensitivity to cracking, this structure is a very effective vehicle to teach a student about fracture mechanics, as well as the ethics and impacts of erecting such a structure. The inherently intertwined nature of engineering and its impact on society is well served by the non-linear nature of the web. Hypertext and multimedia allow for a more personal and interactive educational experience. The intertwined nature of the subjects and the expanse of available information can also make them confusing. The WebQuest framework provides motivation and focus to face the challenges of using the web for educational purposes. The web will perhaps make this experience available to 95% of US classrooms in less than a year.

Chapter One has provided an overview of this thesis project and its objectives. The remaining chapters elaborate on the motivation, background, design, and evaluation of the Cracking Dams web site.