Development of the Laboratory Component of a Materials Chemistry Course for Nonscience Majors

这个项目的重点是为非理科专业的材料世界课程开发新的实验，这也是基础教育专业的必修课。这门课程探讨了日常生活中常见材料--纸、织物、金属、塑料、玻璃、皮革等--的化学，并讨论了每种材料的生命周期，从它在动物植物或矿物世界的来源，到它的加工阶段到成品，直到它被用完或磨损时的死亡，以及它在处置或回收中的最终命运。新的实验允许学生观察微观和原子尺度的图像，进行一些有针对性的化学变化，并测量这些材料的一些重要物理性质。学生们三人一组，解释这些观察结果、反应和测量结果，并找出它们之间的关联。例如，在一项实验中，用扫描隧道显微镜观察到的金和石墨表面的原子结构与它们的密度大不相同有关。在另一个实验中，钠钙玻璃是通过在台式马弗炉中加热沙子(二氧化硅)、纯碱(Na2CO3)、石灰石(CaC03)和碎玻璃(碎玻璃)的混合物而制成的。少量不同的过渡金属碳酸盐(CoCO3、NiCO3、Ag2CO3等)添加颜色，将评估过渡金属浓度和炉膛气氛对颜色的影响。在第三个实验中，测试了像尼龙单丝钓丝这样的合成纤维的拉伸强度，以及产生的与溶剂预处理和平均分子量相关的应力-应变曲线。像这样的实验允许学生观察原子结构，体验现实世界的化学，并得出他们自己关于材料中结构-性质关系的结论，帮助他们理解和欣赏不同材料为什么会有这样的行为。

This project focuses on the development of new experiments for the World of Materials course for nonscience majors that is also mandatory for elementary education majors. The course explores the chemistry of familiar materials from everyday life--paper, fabrics, metals, plastics, glass, leather, etc.--and discusses the life-cycle of each material from its source in the animal vegetable, or mineral world, through the stages of its processing to finished products, to its demise when it becomes used up or worn out and its ultimate fate in disposal or recycling. The new experiments allow students to observe microscopic and atomic-scale images, to carry out some pertinent chemical transformations, and to measure some important physical properties of these materials. The students work in teams of three to interpret these observations, reactions, and measurements and to draw correlations among them. For example, in one experiment the atomic structures of the surfaces of gold and graphite observed using a scanning tunneling microscope is correlated with their vastly different densities. In another experiment soda-lime glass is made by heating a mixture of sand (SiO2), soda ash (Na2CO3), limestone (CaC03), and cullet (crushed glass) in a benchtop muffle furnace. Small amounts of different transition metal carbonates (CoCO3, NiCO3, Ag2CO3, etc.) are added for color and the effects of transition metal concentration and furnace atmosphere on that color will be assessed. In a third experiment synthetic fibers like nylon monofilament fishing line is tested for its tensile strength and the resulting stress-strain curves correlated with solvent pretreatment and average molecular weights. Experiments like these allow students to observe atomic structure, experience real world chemistry, and draw their own conclusions about structure-property relationships in materials helping them to understand and appreciate why different materials behave the way they do.