Scratch is a project of the Lifelong Kindergarten Group at the MIT Media Lab. It is provided free of charge.
Scratch helps you learn the basics of computer science coding. I have taught some workshops on Scratch at FETC and this year will have a poster about it. This page provides the resources that I reference.
http://scratched.media.mit.edu/ has moved (with Dr. Brennan to Harvard at http://scratched.gse.harvard.edu/
K-4 Storytelling and Create Simple Animations
5-8 Create Games
9-12 Games and Simulations for any discipline
Physical Science – Create an animation of Newton’s Laws of motion or thermal energy exchanges
Environmental Science – Create an evolution game that considers scenarios and adaptations
Engineering – Create a game that imitates gravity or solves a building challenge
Technology – Students are learning to code which challenges and develops CRITICAL THINKING!
Links to the resources I uploaded on the Scratched site that you can use as demos: