Discovering the Underlying Mechanism of Snow Crystal Growth and Bringing Modern Laboratory Learning to the Classroom

纳尔逊/摘要9703123 该项目的目标是：1）通过测量晶体生长模型中使用的关键表面参数来发现雪晶形状的物理原因，以及2）通过将实验引入所需的本科生/研究生讲座课程来改善物理气象学的教学。 一种控制冰晶生长的新方法，成功地开发用于测量-16摄氏度以上冰的底面和棱面上蒸汽生长的临界过饱和度。 这些改进需要扩大测量条件的范围，但也将增加对晶体环境的控制。 该方法可用于云物理相关的基础和应用研究，只需稍加修改或不作修改。 五到六个研究质量的实验将被添加到我们现有的物理气象学课程的高年级和一年级的研究生。 每个学生每学期将进行大约3个实验。 实验将长达2小时或更长时间，并被视为家庭作业。 实验将被选择来补充讲座和教师的研究项目，因此可以用于额外的本科研究与适当的教授时，设备可用。 例如：我们的冰晶生长装置的简化版本既可用于实验室练习以说明晶体生长和不同的雪晶形状，又可用于本科生研究项目以测量电场对冰的蒸气生长的临界过饱和度的影响。

Nelson/Abstract 9703123 The goals of this project are: 1) to discover the physical causes of snow crystal shape by the measurement of key surface parameters used in crystal growth models, and 2) to improve instruction in physical meteorology by introducing experiments into a required undergraduate/graduate lecture course. A new method of controlled ice crystal growth that was successfully developed to measure critical supersaturations for vapor growth on both basal and prism faces of ice above -16 degrees Celsius. The improvements are need to extend the range of conditions measured, but will also increase control over the crystal environment. This method can be used for related fundamental and applied studies in cloud physics with little or no modification. Five to six research quality experiments will be added to our existing physical meteorology course for seniors and first-year graduate students. Each student would perform approximately 3 experiments per semester. Experiments would be 2 hours long or more and treated like a homework assignment. The experiments will be chosen to complement the lectures and faculty research projects and therefore can be used for additional undergraduate research with the appropriate professor when the equipment is available. For example; a simplified version of our ice crystal growth apparatus could be used both for a laboratory exercise to illustrate crystal growth and the different snow crystal shapes, and for an undergraduate research project to measure the effect of electric fields on the critical supersaturations for vapor growth of ice.