Middle school is typically the last grade level where science fair projects are required by students, but that does not make it any less important for the student. Because the majority of the grade for an entire semester will be based on a single project, if the student messes it up, it can be a disaster, especially going into high school, where they could be placed in remedial classes based on the low grade.
Thus, these are the most important of all science fair projects at any grade level. Doing well in these projects is imperative.
So what can you do? Well, at the middle school level, the most important part of the entire experiment is the process you follow. Teachers and judges want to see you collecting all the right information, and they want to see you performing calculations on data for the duration of the experiment, as well as the understanding of a control experiment. A poorly designed project will make it impossible to get a good result, no matter how much ingenuity you have.
Project ideas need to be things which are not too easy. Middle School science fair projects must be a great deal more difficult than an elementary level project, and the concepts must be more accelerated.

Magical Experiments