Independant variable for Asprin pill titration with NaOH solution I am assigned to do an independently designed chemistry experiment for school. I want to do titration of Aspirin pills with NaOH solution using Phenolphthalein as indicator. I am struggling to find and independent variable for the experiment. I thought about doing heat, but is unsure about the mechanisms of that. If anyone could help me or guide me in a direction I would greatly appreciate it! 

Thank You!
Independent variable means the variable which you can change easily. Direct titration aspirin is not a good idea as aspirin hydrolyzes into salicylic acid. There are a lot of non-sense high school/college level experiments doing direction titration and ignoring the side reaction of hydrolysis.

The proper procedure of aspirin analysis is by back-titration with NaOH and taking hydrolysis into account. Ask your teacher about it by showing him/her this procedure Back titration of aspirin

Coming back to independent variables...Just now you have another independent variable...comparison of two different methods of titration (direct vs. back). Think of other independent variables and share in your comments.