Do you suppose Darwin, one of the greatest scientists of all time, really did fools' (傻瓜的) experiments? Or did he do experiments that were so simple and basic (基础的) that other people just thought they were foolish?

    Sometimes, people think they already know the answer to a question or a problem．Sometimes, they really do know an answer, but without thinking it is important．

    Charles Darwin didn't just think he knew something．And, he believed all things could be important no matter how simple they seemed to be．

    Suppose you drop pieces of paper that are of exactly the same size and shape．If you drop them at the same time in the same place, they will fall in the same way．Now make one of the sheets of paper into a tight little ball and let it drop along with the other pieces．What happens? You have done an experiment that is so simple that you might think it couldn't be worth anything．

    But this simple experiment is important．It explains part of our present day understandings of physics (物理学) ideas that were worked out long ago by Galileo and Newton．And these understandings set aside some of ancient Greek (古希腊的) physics．

    The scientist sometimes stops to look at very simple things and to think very hard about them．Even the simplest idea, which we might think is foolish, can shake the foundations (基础) of science．