When I was in the second grade my sister April helped me do a "science fair project," except it didn't really count because I was in the second grade and only the fifth graders' got judged. But we went through the motions about. I don't remember the hypothesis or question, all I know is that it was about color and what colors you use to make other colors. I knew my primary and secondary colors thanks to that song they made us sing at church when we were little, so I knew that yellow and red made orange, etc. The majority of the "project" consisted of us using flashlights with transparent blue, red and yellow wrappers on them and directing the light over each other on white spaces to see what colors were made.
Then in sixth grade we had to do a variety of of projects where we were only given primary colors but had to also include secondary colors, that we had to make by mixing the primary colors ourselves.
Anyway, I thought everyone knew the difference between primary and secondary colors. I was wrong. Last night when I got home from work Jessica was working on some sort of diorama or something, anyway, she was using playdoh to cover the bottom of it and using blue, brown and green to represent the ocean, beach and grass. When she ran out of blue she asked me what colors make it. I couldn't believe what she said until she went further, "...is it green and yellow?"
"Red and purple?"
"No. That's makes a redder purple."
"Why won't you tell me?"
"Blue is a primary color, you use mix it with yellow to make green or red to make purple."
"Oh, so what about red and yellow, wait, no, that makes orange."
"It'a primary color!"
"I don't know that that means!"
"You can't make it. You can't make red, yellow or blue."
"So I have to buy more playdoh?"