Today we continued our investigation of diffraction and interference. The lab focused first on qualitative observations of single slits, double slits, and diffraction gradings of various widths and with red and green lasers. The final part of the lab was to make the necessary measurements and then calculate the wavelength of the He-Ne laser. Even just using the classroom meter sticks, students were within 10 nm of the actual wavelength. I think they are starting to appreciate how this phenomenon can be used to create an incredible precise measuring instrument!