Adventures in Coding

Introduction 1    What Is Scratch? 1    Who Should Read This Book? 1    What You Will Learn 1    How This Book Is Structured 2    What You Need to Use This Book 2    Conventions 2    Companion Website 3    Contact Us 3    Adventure 1    Scratching the Surface 5    Coding Is Everywhere 5    Speaking the Language of Machines 6    Knowing Your Coding Lingo 7    Writing Your First Scratch Program 8    Joining Scratch 8    Meeting Scratch the Cat 11    Moving Scratch Around 12    Connecting Blocks 13    Looping Movements 14    Starting at the Green Flag 16    Bouncing Off the Walls 17    Creating a Sprite 18    Handling Collisions on the Dance Floor 19    Slowing It Down 22    Learning the Scratch Environment 23    Exploring the Scratch Project Editor 24    The Toolbar 24    The Stage 31    The Sprite Pane 32    The Sprite Info Pane 33    The Scripts Area 33    The Block Palette 34    The Costume Pane 35    The Sound Pane 36    Working with Colors and Shapes in Scratch 37    Further Adventures in Coding 37    Adventure 2    Where in the World Is Scratch? 39    Setting the Stage 39    Interacting with the Stage 41    Customizing the Backdrop 42    Using a Picture Backdrop 46    Taking a Picture of the Stage 46    Understanding Coordinates on the Stage 47    Taking Center Stage 48    Moving Left, Right, Up, and Down 49    Knowing Your Directions 50    Working with Degrees of Rotation 51    Spinning Sprites 51    Moving a Sprite 54    Stepping 55    Gliding 55    Jumping 55    Creating Random Scratch Art 56    Randomizing Movements 56    Drawing Random Lines 58    Further Adventures in Coding 59    Adventure 3    Using Control Blocks 61    Understanding Code Nesting 61    Branching Programs in Scratch 64    The if ( ) then Block 64    The if ( ) then, else Block 65    Boolean Blocks 67    Making Comments in Scratch 69    Standalone Comments 69    Block Comments 71    Looping in Scratch 72    Looping Forever 72    Stopping Loops with the stop ( ) Block 72    Creating a Counting Loop 72    Looping Until a Condition Is Met 73    Waiting 74    Building the Fly Catcher Game 74    Setting the Stage 75    Placing the Frog 76    Adding the Hippo   Fly 77    Scripting the Hippo   Fly 78    Making the Tongue 78    Further Adventures in Coding 81    Adventure 4    Using Sensing Blocks 83    Learning the Sensing Blocks 83    Getting and Using Text Input 84    Detecting Key Presses 89    Watching for Mouse Moves 91    Using Timing 94    Sensing Touching and Distance 97    Building the Apple Patrol Game 102    Further Adventures in Coding 105    Adventure 5    Using Event Blocks 107    Understanding the Role of Events 107    Working with Key Press Events 109    Using Backdrop Change Events 114    Implementing Sensing and Timing Events 118    Detecting Video Motion 118    Measuring Loudness 118    Waiting for the Right Time 118    Getting Your Message Across 118    Putting on the Big Event 123    Setting the Stages 124    Programming the Ringleader 126    Programming the Ballerina Show 128    Programming the Dinosaur Show 130    Programming the Stage 131    Showing and Hiding Sprites 133    Further Adventures in Coding 136    Adventure 6    Variables and Lists 137    Understanding Variable Blocks 138    Variables Have Names 140    Variables Can Display on the Stage 142    Variables Can Change 144    Scratch Variables Are Persistent 146    Scratch Variables Are Big 147    Making Lists 148    Making a List 148    The Ultimate Party Host 151    Introducing the Lists and Variables 152    Asking for Names and Ages 152    Recalling Names and Ages 154    Further Adventures in Coding 158    Adventure 7    Using Operators in Scratch 159    Saying Hello to the Operators 159    Doing the Math 161    Addition 161    Subtraction 164    Multiplication 165    Division 166    Coding Logically 168    Operating on Text 170    Combining Text with join ( ) ( ) 170    Finding Letters 172    Getting Text Length 173    Understanding Other Operations 174    ( ) mod ( ) 174    round ( ) 174    ( ) of ( ) 175    Make a Math Practice Game 176    Programming Different Paths 177    Making the Addition Quiz 178    Making the Multiplication Quiz 181    Further Adventures in Coding 182    Adventure 8    Using Graphics and the Pen 185    Creating Art with the Paint Editor 185    Using Bitmap and Vector Graphics 189    Understanding the Bitmap Tools 189    Drawing with the Vector Tools 190    Making Slides 192    Use the Pen to Make a Skywriting Plane 198    Further Adventures in Coding 203    Adventure 9    Building Your Own Blocks 205    Making Your Own Blocks 205    Splitting Programs into Custom Blocks 206    Changing Custom Blocks 210    Borrowing Blocks with the Backpack 215    Putting on a Fashion Show 217    Further Adventures in Coding 222    Adventure 10    Making and Using Sounds and Music 223    Using Sounds 223    The Sound Library 224    Using the Sound Editor 227    Editing Sounds 228    Recording Sounds 229    Importing Sounds 231    Forming the Scratch Jazz Band 232    Tuning Up Your Instruments 232    Finding a Drummer 233    Playing the Melody 234    Playing Together 237    Singing Along! 240    Further Adventures in Coding 242    Adventure 11    Exploring the Scratch Universe 243    Visiting scratch.mit.edu 243    Sharing Your Projects 245    The Scratch Community Rules 249    Remixing Projects 252    Interfacing with the Real World 253    Understanding Electricity 255    Understanding Makey Makey 256    Understanding Conductivity 257    Sensing with the PicoBoard 259    Further Adventures in Coding 261    Appendix A    Installing the Scratch Offline Editor 263    Installing the Scratch Offline Editor on Windows 263    Installing the Scratch Offline Editor to Your Mac Operating System 268    Other Resources 275    Appendix B    Testing Your Programs 277    Practice Proper Planning 277    Ask Other People to Test 278    Look for Possible Invalid Input 279    Use Comments Often 280    Test Early and Often 280    Keep Track of Tests and What Breaks Things 280    Use Custom Blocks 281    Use Sliders for Numbers 281    Keep Learning 282    Keep Practicing 283    Glossary 285    Index 289