Por si algún profe quiere investigar sobre estas 70 apps y ver si le son de utlidad. Yo uso algunas // The 70 Best Apps For Teachers And Students - Edudemic. These are listed as itunes apps, but I'm sure a lot of them can be found for Android as well.
Eyewitness to is a site that lets students select a period in history and see personal stories of people from the time. A nice combination of a great deal of information and many historical photos and drawings that bring learning to life.