Natasha Singer:

At a New York state elementary school, teachers can use a behavior-monitoring app to compile information on which children have positive attitudes and which act out. In Georgia, some high school cafeterias are using a biometric identification system to let students pay for lunch by scanning the palms of their hands at the checkout line. And across the country, school sports teams are using social media sites for athletes to exchange contact information and game locations.

Technology companies are collecting a vast amount of data about students, touching every corner of their educational lives — with few controls on how those details are used.