Need short educational Science videos of 4-5 minutes length - Grade 5+

Do note that you are bidding to create 20 Educational Science videos of length 4-5 minutes each. Only those having the knowledge of how to create educational videos should bid on this project. Also the topics can range from Physics, Chemistry to Biology. However, I would prefer it to be Physics for all the videos. The length of the videos will be around 4-5 minutes each. The videos should address topics for Grade 5+ Students and should not be for small kids. Also these should not be true copies of other educational videos on Youtube. Also the videos must be original creation with all rights transferred to me for publishing. i.e. you cannot use these videos anywhere. You will have to provide a written undertaking to this effect once you are chosen for the project. This 20 videos project is just the 1st part of the project and will need several hundreds later. So consider this as a very long term project. Also note that you must have all the software and hardware at your disposal to create khan academy style videos. If you provide a two minute sample demo, your chances for being chosen for this project will increase as I am looking for high quality presentation. If you have any questions do let me know.