My early approach with Snap!, this semester, is to develop minimal Snap! skills in my students so that they can comprehend simple scripts that apply knowledge they already possess. Today I had students watch this script execute. In it a sprite expresses the result of the mathematical expression (2*t +1) for t = 0, 1, 2, 3, 4, and 5. Students then modified this script so that the sprite expresses the positions of their lab vehicle at two second intervals using the simple linear equation they derived for their vehicle's motion the previous day. They quickly saw the sprite reciting values that matched the position column of their data table. By doing this students sensed the significance of their equation by seeing it generate the original data when programmed in Snap! This significance of the equation was always part of the post-lab emphasis, but I knew students only looked at their derived equation as something their teacher wanted them to write. This allowed me to ask: Do you think we can use these values to make a sprite move on the display to simulate motion? Students know enough about Snap! to say "of course!".
The next step was to present this heavily scaffolded script in which the students are tasked to complete so that a turtle sprite moves at a rate of 20 pixels/second, having started from the 0 pixel x-position. This was an easy task for most, and an opportunity for me to work closely with a few students who were struggling. There was minor glee from some students watching the turtle sprite move in 20 pixel bursts across the display. I narrated the flow of the script and clarified what the set x to block does. This gave me an opportunity to emphasize that the equation obviously represents the motion because we used it to make the motion. I felt this Snap! exercise added value to the usual routine.