Flipgrid is a terrific video app designed to amplify student voice and empower students as learners. It allows unlimited video responses to teacher questions and includes all of the necessary components to safely and fully engage students online, including password-protection, teacher moderation, transcripts, iOS and Android apps, and more.
http://classtechtips.com/2017/02/01/flipgrid-student-voice-video-app-classrooms/