Candy bar science has traditionally focused on how candy was made. Thousands of students each year design candy science fair projects that demonstrate how sugar undergoes transformations during the candy making process. Many others simply use rock candy experiments to show how sugar crystallizes from a solution.
While these project ideas may result in a passing science grade they are, in a word, boring. Boring projects are not going to do well at science fairs. Judges will not give your project a good score and they will not forward your project to the winners' circle.
If you want to produce a winning candy science fair project you need to develop an interesting project idea. Fortunately, there are several ways that you can do this.
The first way to develop an innovative candy bar science project is to looked as a component of candy that does not related to the chemical and physical changes that sugar undergoes during the candy making process. Instead you will want to look at other science concepts related to candy making or to candy in general. For example, you can examine how candy's ingredients impact a body. You can examine how much energy is produced by eating candy, how long the energy lasts for and how it impacts the biochemistry of the person eating it.
Another way to develop an innovative candy project is to take a look at the psychological impact that it has on people. You can research why candy is so popular and why it seems to make us happy.