Animation Desk is an iPad app (free and premium versions available) for creating short, animated videos. The app allows you to create drawings using just your finger on your iPad's screen. In the free version of the app (the version that I tried) you can create up to 50 scenes in each of your projects. In each scene you can include as little or as much as you want to draw on the canvas. There are a few different brush and pencil effects that you can use in your drawings. The opacity of the colors you choose can be altered too. When you have completed drawing all of your scenes hit the play button to watch your animation unfold. If you're happy with your animation you can export it to YouTube. If you don't like an aspect of your animation, you can go back and edit one scene or all of the scenes.
Applications for Education
Using Animation Desk could be a good way for students to make short animated video clips to use as part of larger digital storytelling projects. Animation Desk could also be used by students to draw and create demonstrations of things like the orbit of the solar system or another concept that is well suited to demonstration through simple stop-motion video.