Seesaw. Seesaw is a free iPad app through which students can create a portfolio to document the things they have learned. Students can add artifacts to their portfolios by taking pictures of their work (in the case of a worksheet or other physical item), by writing about what they've learned, or by shooting a short video to record something they have learned. Students can add voice comments to their pictures to clarify what their pictures document.
To get started with Seesaw create a free classroom account. Students join the classroom by scanning a QR code (you will have to print it or project it) that grants them access to your Seesaw classroom. As the teacher you can see and sort all of your students' Seesaw submissions.
Seesaw allows parents to create accounts through which they can see the work of their children. As a teacher you can send notifications to parents when their children make a new Seesaw submission.
Applications for Education
As is pointed out in the video above, portfolios made through Seesaw could provide excellent information to share with parents at conferences. It's also a good app to use in an art class in which students have created things that aren't easy to file and keep track of for the entire school year. Students could take a picture of their artwork then talk about it in the Seesaw app.
Update 6:44 EST 1/23 - Larry Ferlazzo covered this app last night (I didn't realize until now) with a great take on its potential for use with ELL/ESL students.