That sounds amazing! I wonder if we could get you setup with the outreach program at the University of Arizona, which has an entire class dedicated to having undergrad / graduate students share optical knowledge with others.
In the meantime, I have always been fascinated with the physics of rainbows, and put together a small write-up on them from a geometrical optics perspective:
I think this make be slightly too complex for the 8th graders (unless they have already learned about geometry), but I think the concept of explaining optical phenomena that we observe in our everyday lives could be really fun!
I’m thinking of a few experiments that the kids could play with to study the effects of light. One could be showing them how a glass of water bends a laser beam, another could be a prism and showing them how it can separate light into colors, etc.
I will also think about what kind of online resources might exist that have some other ideas. I definitely support the sharing of optical knowledge!