Hi Nicole

Your choice of song and how you sing it depends on the character you are going for. On the whole, the songs in Grease are belt numbers, but nobody sings an entire song in belt - it would exhaust the singer and probably bore the audience! Singing is about expression after all.

When the music in a musical theatre number indicates that the notes are to be sung double forte (fortissimo ff) you are probably going to be belting. Also where there is a strong emotional message in the lyric. Belting is basically happy yelling, but it is not something you should be attempting as a singer without some help from a singing teacher because it is a potentially damaging voice quality. Done well it is also thrilling.

If you are serious about your singing, find yourself a good teacher, someone who knows about how the voice actually functions and who can give you clear instructions on what to do to obtain the sound you want. In my view, imagery (imagining the sound coming out of various parts of your face etc) is not adequate as a singing teaching tool, although it may help an accomplished singer to fine-tune their expressiveness.

Good luck with your audition.