Exigence:
Exigence is a very tricky aspect of rhetorical situations. Not many people in the beginning understand what it truly is. What is the difference between purpose and exigence? Purpose is the call to action because of a certain event but the exigence is the issue itself. It is what has prompted you to the piece you did.
For instance, when we created the balloon-powered car, the purpose was to inform people on how to make a balloon-powered car. However, the exigence was that, there was a science fair coming up and students needed to learn how to create proper scientific projects without any outside influence.
Another thing about exigence is that different papers can have the same exigence but different purposes. For instance, in our project proposals all the groups focused on the Hurricane and how to deal with it. Some people wanted to shoot radio waves, and some people wanted people to download an app. Although both served the purpose of persuasion, what they were persuading was different, however the exigence was the same. We needed a potential future solution for environment health and safety issues.