A Macroscale Model for Hands-On Activities Demonstrating Transmission Electron Microscopy

摘要

Although nanotechnology lessons are increasingly integrated into curricula, students still face significant challenges in understanding the characterization techniques used to investigate nanotechnology. Many characterization techniques, such as transmission electron microscopy (TEM), are prohibitively expensive for primarily undergraduate institutions and completely inaccessible for high schools and local outreach programs. When TEMs are accessible, opportunities for hands-on use are still limited due to logistics and costs for instrument time. In this project, we present a low cost ($50 USD) macroscale TEM model that uses cyanotype paper for "imaging" and is constructed of materials available at local hardware and pet supply stores and chemistry stockrooms. This model allows students to investigate properties of TEM micrographs including thickness contrast, diffraction contrast, plan view, and tilt series imaging through a series of four hands-on activities in an active-learning setting. The four activities are identification of mystery objects from student cyanotype "micrographs", sizing objects from their micrographs using a scale bar, sketching the structure of a mystery 3D object from acquired tilt series images, and developing unique micrographs with objects of the students' choice and predicting features of the resulting images. The TEM model and associated activities were tested with groups of STEM (Science, Technology, Engineering and Mathematics)-interested high schoolers and were found to enhance student engagement, enjoyment, and understanding of certain properties of TEM micrographs.