My 6th grade science teacher taught us that blood is red but that some people think it is blue until it touches air because our veins look blue under our skin. He explained how the different wavelengths of light are absorbed differently and they was why it looks that way. Two years later my 8th grade science teacher taught us that blood is blue until it touches air. She was not happy when I told her she was wrong. I even explained it and told her to go talk to the other teacher if she still did not understand. She still would not listen to me. Over half the class was in the same sixth grade class as me but I was the only one that either remembered or was willing to stand up to the teacher. I finished losing faith in the education system on that day.
The first time my wife (girlfriend at the time) went to my parents house my dad showed her his coprolite collection. That was over 20 years ago and she is still with me. So from my scientifically significant sample size of one, I can confirm that it indeed works.