Day 129: A Small Air Gap Between Two Glass Plates

What causes the colors we see when we look at two plates of glass that are separated by a small air gap?

Before we could explain that, we had to talk about color. I wanted a short discussion about how we see color so we'd have some ability to say whether the colors of the two plates of glass looked more like rainbow colors or subtractive colors. We had so many questions about color. Color is so interesting, with tetrachromancy and bee vision being obvious tangents. We'd love to talk about it more, but I hurried everyone to looking at the plates of glass. So many students are gone Thursday and Friday for (another) robotics competition that I wanted to make sure all the new concepts were introduced today.

We saw the colors, and they were cool. They did not look like rainbow colors.

We then explained them by looking for a path length difference. But I didn't let them figure it out enough. Next year, I should make them do more of the thinking.