Optical Transform (X-ray Diffraction) Transparencies
When students have a Optical Transform (X-Ray Diffraction) Transparency and laser pointer, simulating X-ray diffraction becomes a hands-on activity. Students see the diffraction patterns by shining a laser through the transparency and projecting the patterns onto a screen or wall. The four different diffraction transparencies have these patterns:
- Unit Cell: examples for changes in unit cell size, angle, and shape; for centering with like and different atoms; for glide symmetry
- Discovery: provides multiple examples for changes in orientation and in unit cell size; particularly appropriate for use in student investigations
- VSEPR: complements discussions of molecular geometry such as VSEPR rules and illustrates one way that geometry differences can be detected in a triatomic molecule
- Plane Groups: provides additional examples for the systematic absences that occur for centering and for glide symmetry
A source of visible laser light is not included, but any laser pointer will work. Transparencies are sold in sets of 10 by type. To use these transparencies effectively you need one copy of the Optical Transform (X-Ray Diffraction) Kit which includes directions and contains one each of the four diffraction transparencies.
Create a hands-on activity even if there's only one laser pointer available for a group of students. While the teacher shines the laser pointer onto a screen or wall, each student holds their transparency up to their eye and looks through it towards the projected laser pointer spot. Students will see the diffraction patterns produced by the corresponding sections on the transparency. Students discover how the different patterns on the transparency affect the shape and size of the diffraction pattern they observe. This method also works well for younger students.