化学专业毕业论文外文翻译--弯曲它，伸展它，锤打它，打破它：材料化学研究

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1、Bend it, Stretch it, Hammer it, Break it: Materials Chemistry Applied Abstract Making chemistry both accessible and interesting to middle and high school students can be difficult. Convincing middle and high school teachers that they will learn something new and applicable from a professional develo

2、pment workshop in chemistry can be equally challenging. This paper describes the use of material science as a means to enhance interest in basic chemical concepts. By making use of familiar materials, it seeks to reveal the applicability of chemistry to everyday life. Metals, semiconductors, and pol

3、ymers were the materials at the heart of this course for secondary level teachers. Properties of these materials were investigated in hands-on activities and firmly connected to the bonding type and structure in each material through interactive discussion. The course itself will be described, and a

4、 few of the activities will be high-lighted. Teachers responses to daily surveys and final evaluations will also be discussed, and future directions will be addressed. Introduction As the study of matter, its properties, and its reactions, chemistry plays an integral role in every aspect of every li

5、fe. However, chemistry can be a complex and abstract subject, and students often struggle with learning it. Research into misconceptions and problem solving in chemistry illuminates this difficulty (Bodner, 1991； Kind, 2004； Nakleh, 1992). The struggle with chemistry extends beyond the students to t

6、he teachers of chemistry teaching an abstract, complex subject, and making it accessible, relevant and applicable to students, is challenging (Gabel, 1999).The authors know this from experience in teaching introductory chemistry to college students and hear this anecdotally from colleagues teaching

7、in middle and high schools.teachers attitudes toward teaching chemistry can be just as critical to student success as their knowledge of the subject. “In all education,especially science, the teacher is the enabler, the inspiration but also the constraint. their instructional behaviors are influence

8、d by their attitudes towards science, a fact that does not go unnoticed by students” (Vaidya, 1993, p.63). Also, the middle and high school years are critical ones for science education. Studies have shown that as students get older, their attitudes towards science become less favorable (Fleming & M

9、alone, 1983； Sorge, 2007). One such study indicated that science attitudes show a “precipitous drop” when students make the transition from elementary to middle school (Sorge, 2007). This particular study suggested that the observed changes in attitude may be connected to developmental changes in st

10、udents and recommended further research (Sorge, 2007). Another study suggested that older students inability to see themselves using science outside the classroom may be connected to their perception that science is about reading and lecture and not about performing activities (Barman, 1999). Moreov

11、er, students attitudes toward science can be “most significant” in determining whether or not they will continue with further science study or choose science as a career (Osborne, 2003, p.1055). With these issues in mind, a 40-hour professional development (PD) course was created for middle and high

12、 school teachers. The focus of this course was materials chemistry, an area rich in applicable content relevant to both teachers and students lives. In order for students to fully appreciate science and value learning it, science courses throughout K-12 grades need to clearly show the relevance of s

13、cience taught in the classroom to everyday life (Barman, 1999). To make chemistry accessible by showing how it relates to materials used in everyday life, we placed the chemistry of bonding into the context of the resulting material properties. In just the last century, our society has become increa

14、singly reliant on modern materials such as plastics, composites, and semiconductors, and all of these materials have extended the boundaries of our technological capabilities (Sass, 1998). The relevance of materials like these to students everyday life is obvious, and this allows us to make chemistr

15、y more interesting and accessible. The connection between bonding type and observable material properties gives teachers a way to update their own knowledge and teach a basic concept with renewed interest and more applicability. Figure 1 below illustrates the connection and flow of the concepts cove

16、red in this course. The materi-als themselves are the basis of this course these are the observables that the teachers (and students) can relate to and connect to in their everyday lives. The materials studied were all solids, and, consequently, the bonding in solids and the theoretical basis of tha

17、t bonding (band theory) are necessary components to the course. Structure and bonding are intimately connected and also determine properties of solids. Thus, the concepts come full circle to answer the question, “How is the bonding in a material related to or responsible for the observable propertie

18、s?” This course has been offered twice with a total of 26 teachers participating, and it is part of ongoing work between the Central Coast Science Project (CCSP) and teachers from partnership schools. The CCSP, one of 18 California Science Projects (CSP, 2009), is a collaborative endeavor between Un

19、iversity science faculty and local school districts to improve science education for all students. The main presenters for the course were Cal Poly Chemistry faculty； collaborators from Materials Engineering (MATE) played a key role in the first incarnation of the course. Undergraduate chemistry and

20、 materials engineering students developed some of the background content and adapted several of the activities in the first year. The work of two of these students became their senior projects, which are required for graduation from this university (Barber, 2005； Coles, 2005). Table 1: Materials Che

21、mistry Content Covered and Representative Activities Content Representative Activities Demonstrated Material Property BondingConcept(s ) Applied Basics of Bonding Melted Away Melting point Differences in ionic andcovalent bonding Metal or Nonmetal? Conductivity, malleability Differences in metallic

22、and covalent bonding Basics of Solids Solid State Models Structure of solids at atomic level Bonding in solids Crystals Up Close Structure of solids at macroscopic level Bonding in solids Properties of Metals, Defects Drop the Noodle Comparing heat conduction in metals Metals conduct heat well due t

23、o delocalized nature of bonding electrons Metal Working & Strength Malleability and strength of metals Metals are malleable and strong due to delocalized electrons and presence of defects Band Theory ExploringConductivity Part 1 Conductivity of materials as a function of temperature Comparing conduc

24、tors, semiconductors, and insulators Semiconductors: LEDs Exploring Conductivity Part 2 Conductivity of semiconductors as function of temperature and composition Conductivity of semiconductors depends on what it is composed of and on temperature Polymer Basics and Reactions Making and Recycling a Po

25、lymer Stretching and elasticity of different polymers Cross-linking in polymers Polymer Structure and Properties Polymer Absorption Absorption properties of different polymers Structure of polymer Tensile Strength Test Stretching force different polymers can withstand Composition and structure of po

26、lymer Density Challenge Density of different polymers Composition and structure of polymer The intention behind the course is not to “reinvent the wheel.” All the parts of the course were already in existence. The course was based on the authors teaching experience in and content from an engineering general chemistry course (Bailey, 2004). The activities were adapted