Don't cheat:
http://www.pewresearch.org/quiz/science-knowledge/
Yes, I got a perfect score. I wouldn't have posted this had I done poorly.
It would be interesting to see how this breaks down by major. I have a business administration degree, a field for which I have absolutely no aptitude. I was in engineering and was taking senior level courses making pretty good grades when I changed majors (a decision I regret greatly), so I do have a science background.