A small particle of fire that flies off when something burns—a spark. Figuratively, a spark can mean the start of an intense exchange or emotion.
金属を打ち合わせると火花が散った。
Sparks flew when the metals were struck together.
二人の会話にはいつも火花が飛ぶ。
There are always sparks flying in their conversations (they argue energetically).
花火の小さな火花が夜空に舞った。
Small sparks from the fireworks danced in the night sky.