Are you looking for a word that fits that definition? In that case I'll pretend we're playing jeopardy and say "What is INVENTION?" That's my guess anyways. I'm not entirely sure what you're looking for, but maybe this is it. After all something people make could be a tool, but the "certain period of time" makes me think its referring to something new.
Something created by humans? there are alot of things that were created by humans: phones, houses, buildings, watches, clocks, clothes, computers, speakers, microphones,studios, cars, motorcycles, bicycles, books, and much more.
