Idiom of the Day
a person who acts as if he or she knows everything
The librarian is a know-it-all and nobody likes to be around him.
Biggest things in the World
Vacuum chambers are used to recreate the conditions of space: to see, for instance, how matter clumps together in the absence of gravity or to test components of space suits. There are some very large ones out there, but only one so large that it s capable of performing environmental testing on acompletely assembled spacecraft: the Plum Brook chamber in Sandusky, Ohio.