Last time, me and my friends did some experience at school. The experience about yeast. First we need 2 bottles, bottle A and bottle B. Then some sugar, water and fermipan yeast. We put some yeast and water in bottle A without any sugar and we put some yeast, water and sugar in bottle B. Don't forget the balloons too. Cover the top of the water with balloons and wait for some times... Then the balloons on bottle A will grow slower than the balloon on bottle B. Its all because yeast will grow faster with energy. The sugar the dissolve and become the energy for the yeast. :)
Some links to help you know more about this experiment :)
