Science in the Kitchen

Sabrina came home with a science project on 10/8, due on 10/15. She needed to come up with an experiment that she could do following the scientific process. The question she came up with was, "Why do we need yeast in bread?" So, Sabrina mixed up 2 batches of bread dough - one with no yeast and one with yeast (originally we were thinking of doing another batch with double the yeast, but we ran out of time).