I am currently researching the effects on student motivation when passion-based teaching methodologies are employed. I am having trouble narrowing down a validated measurement tool for my research. Any assistance is greatly appreciated.
As Alexis noted earlier you can find best scales in SDT website.
Also, I have used Learning Self-Regulation Questionnaire (SRQ-L) in my research for measuring self-regulations and behavioral regulations in learning, that this questionnaire includes Reasons for Learning Questionnaire, which there are twelve questions in two items, autonomous and controlled regulations in learning classes. (its just for motivation).
Have a look at the Student Motivation and Engagement Scale (Andrew J. Martin, 2004,2005, 2007). there is one for High School pupils (11 -17 yrs) and one for Junior School pupils (6-10 yrs). I have used this scale very successfully in schools.