fanfiction-harry potter:THERMOS!, by susieboo

THERMOS!, or, How a Muggle-Born Brought a New Age of Spell-Making to Hogwarts (Entirely by Accident)
susieboo

Summary:
Muggle-born witch Phoebe McDevitt just wanted her tea to stay warm during class. She didn't expect to accidentally start a spell-making craze among her classmates.