Unit 1 Lab 5: Block Types and Calculations, Page 1

PG on Revision to U1: Tailor this work on calculation so that we can use it to continue the project, making n rows of n tiles to fit the screen. 5.1 is arbitrary and without context. Treat stage costume as side info. Use xpos, ypos only to determine row and column in array the sprite has been dragged to. Ignore direction until needed. Build 5.2, 5.3 in context of locating sprite on array.
Need to support students in learning geometry of angles and diagonals somewhere
Paul, whatever you keep here, consider if they should be saving at the end. --MF
Also, there was a GH comment suggesting that we "introduce the students to animation... This would be beneficial for their create task (ap exam final project)."
MF: Consider including something like the python tutorial L, T, and checkmark problems...
GH Feedback 10/27/15: LAb 5 as a whole just seems kind of disjointed. As if it is just various odds and ends

This lab will summarize, clarify, and extend the ideas you have been studying in Unit 1.

Change the stage's background to xy-grid so that you see the coordinate plane grid and axes. The instructions and video below will remind you how.
1. In the Sprite Corral (just below the screen), click the Stage button.
2. Then, choose "Backgrounds" from the snap File menu, .
3. Choose "xy-grid.gif" to show the grid.
You will have to select the Sprite in the Sprite Corral to make the Motion blocks reappear. The Stage doesn't have Motion blocks.
In the blue Motion palette, check the gray check-boxes next to the , , and blocks. That creates "watchers" on the stage, boxes that show the x and y coordinates of your sprite and the direction it is pointing.

Drag the sprite around with your mouse. Also use move and turn to control the sprite. Notice which actions change which values.
Experiment to determine which part of the sprite the coordinates are describing. (Head? Tail? Center?)

Your stage should look like this with axes, a grid, the origin, and 3 watchers: x position, y position, and direction.

Some programming languages treat the top left corner of the screen as the origin: coordinates get bigger as you move down and right, with no negative coordinates. snap uses the same coordinates you use in algebra.

Brian, I know you don't like wikipedia links, so I'm flagging them all for your approval (please delete this comment) or removal (please delete link tags and this comment). Thanks --MF

snap 's coordinates work the way you've learned in mathematics. Direction in snap works differently. snap uses 0 to mean "pointing North" (up) and 90 to mean "pointing East," (right) and so on. This is how compass directions are expressed.

(Mathematics uses a different convention: 0° for pointing in the positive direction along the x-axis, that is, toward the right, increasing as we turn counter-clockwise toward the north (90°) and beyond.)

Sprite Position and Direction