You can also read how google shows option to search for any result through other search engines like yahoo, Bing , Wikipedia and many more ! even thought there are search results in google . This is some weird to hear as why does google wants to suggest user to search other search engines LOL .Similarly i didn't know and i am sure that
If you know then , you are top googler :D
Well , even if you enter more words , results are shown but , some not so keywords like "for" are not considered by Google Bot and you wil definitely get results not containing "for"
There are many such unknown facts of Google , and many of them are left to be searched for , Do you know some of em ?