She did it in her newest music video. Firework is a good song, but the music video is definitely a must to watch. See the video here...
Firework is a song that will boost your confidence.
"'Cause baby you're a fireworkCome on, show 'em what you're worthMake 'em go, ohAs you shoot across the sky"
For me the song tells you that you must do what you need to do and show them what you got. It is like the Nike's "Just do it."
Katy Perry in the video of Firework
And by the way, Katy Perry's purple highlights is love ♥.