There are some really good histoy apps around for iOS. Some of them may well have Android versions if you check. HistoryApps has a number of freed educational history apps which seem to be for younger children or those young at heart. TechRadar recommends apps for an older age group but most of them seem to be paid apps. There are two free ones , though, which are well endorsed: National Geographic’s Titanic and Streetmuseum’s Londinium. Timeline Eons is another really good free app for history. eLearningIndustry has free apps for teaching American history.