I think this would be a very interesting science fair project. However, you should run it by your teacher(s) first to get it approved.
Could you specify what exactly you mean by positive or negative wording?
You could test this by coming up with two lists of questions. List A would have some with positive wording and some with negative wording. List B would have the same questions, but change the ones that were positive in List A to negative and the List A negative ones to positive.
Then, split your test subjects into two even groups. Let one group answer the questions on List A; let the other group use List B.
Here are some things to figure out. (1) What do you think the controlled, dependent, and independent variables would be? (2) What would your hypothesis be?
Let us know what your teacher says, and post back with further questions if you have any.