- corrosioon rate experiment

Hi guys, I need some help here. I'm going to do an experiment based on the topic "dissolving rate of corrosion on metals." I've done an experiment and submitted the report to my teacher...but I didn't get a high mark since she said my experiment should be quantitative type of experiment instead of qualitative type meaning that it has to include something measurable so that there will be graphs, table, etc. And now I have to redo it again but I got no idea at all of what should I do. Help me out guys...I lost my appetite and everything because of this problem. Thanks a lot.
:cry: