Scratch is one of those really cool tools that can be downloaded for free here and many schools already use it to teach elements of control and programming. I've used it with both Year 4 and Year 5 children to program simple games, mainly based on the resources based on the scratch cards on the main website.
Although I already know a little bit about scratch I still signed up for the scratch workshop at the Naace #3mhothouse as it's always good to find out more.
The workshop was given my Mark Dorling who is a secondary school teacher and also runs the Digital Schoolhouse where you can find lots of free resources (also type digital schoolhouse into youtube to find lots of scratch videos).
He started off the session by getting us to think logically - what list of instructions would you write to perform the Moonwalk dance (he did a demo!) or to work a set of traffic lights? This is the basis for programming - breaking the problem down into its parts.
Mark then talked us through how to create a simple calculator using scratch (we only got as far as the addition part but I'm sure it would be fairly straightforward to extend). I took photos incase you want to have a go yourself.
First, create a button (sprite - can be any design you like but it resets the calculator to 0):
Then program your button with the following:
Program the stage with the following:
And finally add another character (sprite) and program with the following:
This makes your little dude tell you whether you are correct or not.
And that's all there is to it!