This site is clean, clear and concise in providing thoughtful overviews on many areas related to optics. I have used this site in my student teaching classes when covering colors, color mixing, and light in the arts. The diagrams are clear and show up well on a large screen. My point gets made in a fast and efficient way. The students often take note of the site and some use parts of the site in lessons that they develop for their elementary and middle school students.