Will fake gerbera daisies float?

My sister is getting married in a few months and would like to have gerbera daisies floating in water in rose bowls for her centerpieces. I used fake roses for my wedding and it worked out just fine. But she had tried a couple different fake gerbera daisies and they all seem to sink rather than float. Anyone know why? Anyone use fake gerbera daisies in water for centerpieces?