Sliding scale question types are useful if you want to keep your respondent excited about your survey.  Instead of throwing a bunch of multiple choice questions at the respondent, switch it up a little.  An example of a good question to use on a sliding scale would be "how happy are you with your Professor?"  Qualtrics provides different sliding scale icons (smiley face, letter grade, etc.) — the respondent can then slide a tab up or down a scale to make the smiley face smile or frown, based on how happy they with their professor.

Diversified question types are proven to improve attention spans in survey takers, so make the most of them!