I purchased Camtasia Studio over the summer and have used it to create tutorials for teachers that use our school's gradebook program. I just discovered a feature in the software that allows quizzes to be embedded in a video. I create Power Points all the time that are designed as mini tutorial/review sessions for my students. Camtasia has a plugin for Power Point that allows you to capture screen video and audio. So I decided to do a screencast for my isotope review/tutorial and then embed questions that students can answer to check their understanding. I'm very pleased with the results. I think I might do screencasts in the future for subs to run during an absence. It will be like I'm in the classroom, when I'm not.
This a favorite demo of mine that I have recently re-shot in HD. It's a dramatic demonstration of how the rapid condensation of water can create a vacuum.
The particles (molecules) of a solid, liquid, and gas act differently because they have different energies. The video shows how to model those differences to students.