BrainPop movies may be used to introduce a new lesson or topic, for illustrating complex subject matter or to review before a test. Content is aligned to USA state education standards and is searchable by topic or state standard. In addition to movies, the site displays quizzes, educational games, experiments and other related content that students can use interactively to reinforce the lessons in the movies. BrainPop products are compatible with PCs, Macs, projectors and interactive whiteboards, as well as applications for tablets and smart phones. No downloading, installation or special hardware is required. The movies feature recurring characters such as the robot Moby, Tim (a teenager, at BrainPop) and Annie (a younger girl, at BrainPop Jr.). Most of the movies begin with the characters responding to correspondence and end humorously, often with Tim getting annoyed at Moby or vice versa.