When a sixth grader asks, “Why is grass green?” I’m pretty sure they don’t expect an answer that dives into chemistry and evolutionary history. And yet, that’s what they’ll get! While many of us—even scientists and educators—have a logical (but incomplete) answer ready to go, a little more digging turns up connections to blood, the nuances of photons, and even a mysterious ancestor that may or may not have existed in the deep past.