What are the differences between a petri dish and an agar plate in microbiology experiments?

A petri dish is a shallow, round glass or plastic dish used to hold agar, a gel-like substance that provides nutrients for growing microorganisms. An agar plate is a petri dish containing agar with added nutrients and is used to culture and grow specific microorganisms for study. The main difference is that an agar plate contains nutrients specifically tailored for the growth of certain microorganisms, while a petri dish may not contain any added nutrients.