Over the last 50 years numerous innovations have changed the teaching of the sciences, particularly in universities where adjustments were made to accommodate large numbers of students in the classroom. The changes range from the introduction of mark-sense machine scoring to the publishing of detailed ancillary pedagogical materials to the use of PowerPoint presentations. These innovations often perform as expected and intended. Nonetheless, the unintended consequences of their use often go unnoticed, but they, too, can influence the education of students, profoundly. Examples of innovations and their various consequences will be described and discussed.