I just had two students walk out of my classroom. I showed them an article about Katherine Johnson, a black woman who worked in the computer pool crunching numbers for the American Mercury space missions. We were looking at how she faced adversity in her career (e.g. access to education, segregation, exclusion from men-only briefings). The students saw the photo of Johnson and said that she wasn't black. They even googled other pictures of Johnson and persisted with their claims. I tried to tackle this from a variety of angles before they lost patience with me and left. I am dealing with consequences as we speak. Please can anyone advise on how I should (or should not) approach this with them?