Flipgrid is a video discussion platform that allows students to record responses to teacher-posed questions or topics. This software was recently acquired by Microsoft and it has recently been changed to be a freely available tool. FlipGripd is similar to the popular VoiceThread.
Check out 15 Ways to Flipgrid in Higher Ed
This article, The Power Of Voice – Reflective Collaboration, talks about how to manage the limitations of the free version of FlipGrid.