As you watch them jump and hit the top, you will notice something interesting. The fleas continue to jump, but they are no longer jumping high enough to hit the top.

当你观察它们跳跃并且撞到盖子的时候，你会发现一件有趣的事情，跳蚤会继续跳，但是它们不再跳到能撞到盖子的那个高度。