Four our huge IB Group 4 science project, we are doing an experiment where we are placing different brands/types of shaving creams into a vacuum bell jar and measuring the expandability of each cream. Then we are having men test out the shaving creams, and seeing if the expandability of the shaving creams relates in any way to user satisfaction. Now, this is a random idea we thought of, but I'm having trouble finding out what in shaving cream causes it to expand....air trapped between molecules? but does anyone know what difference between shaving creams could cause one to expand more than the other? and what exactly does shaving cream do? does it provide a cushion between razor and skin? thanks to any comments!