Programming · Grade 6 · Chapter 3
Intro to Scratch 3.0
Mastering the workspace, stage coordinate geometry, block typologies, and event-driven scripts.
Lesson Overview
Learning Objectives
- Navigate the IDE: Master the 4 key regions of the Scratch 3.0 workspace interface.
- Coordinate Geometry: Understand the X (-240 to 240) and Y (-180 to 180) stage grid.
- Block Typology: Differentiate between Hat, Stack, Boolean, and Reporter blocks.
- Sequential Scripting: Build precise movement, look, and sound sequences triggered by events.
Grade 6 Elevation
Moving Beyond Basic Drag & Drop
Grade 5 Thinking
Dragging random blocks and clicking them one by one to see what happens on screen.
Grade 6 Engineering
Planning precise X/Y paths, optimizing block sequences, and structuring multi-sprite interactions.
Debugging Case Study
"Why Won't the Cat Move?"
Maya assembled 5 Motion blocks: move 50 steps, turn 90 degrees, say [Hello!]... but clicking the Green Flag does absolutely nothing!
Smartboard Prompt: What vital component did Maya forget at the very top of her code stack?
Workspace Anatomy
The 4 Quadrants of Scratch IDE
1. BLOCK PALETTE
Code Categories
Color-coded library (Motion, Looks, Sound, Events, Control, Sensing, Operators, Variables).
2. SCRIPTS AREA
Coding Workspace
The middle area where you snap blocks together to form active scripts.
3. THE STAGE
Visual Preview
The 480x360 pixel window where your sprites come to life.
4. SPRITE & BACKDROP PANE
Object Management
Where sprites are added, renamed, resized, and backdrops are chosen.
Stage Geometry
The Cartesian Coordinate Grid
Every position on the stage is pinpointed by an (X, Y) coordinate pair.
X Axis (Horizontal)
Left border = -240
Center = 0
Right border = +240
Y Axis (Vertical)
Bottom border = -180
Center = 0
Top border = +180
Center Origin
The exact middle of the stage is (X: 0, Y: 0).
Syntax Rules
Block Typology & Shapes
HAT BLOCKS
Event Starters (Rounded Top)
e.g. when green flag clicked — Always placed at the top to initiate execution.
STACK BLOCKS
Action Commands (Notched)
e.g. move 10 steps, turn 15 degrees — Connect top and bottom.
BOOLEAN BLOCKS
True/False Conditions (Hexagonal)
e.g. <key [space] pressed?> — Fits into condition slots inside if statements.
REPORTER BLOCKS
Data Values (Rounded Oval)
e.g. (x position), (score) — Returns numbers or text to other blocks.
Core Categories
Essential Motion Blocks
go to x: 0 y: 0 // Instant teleport to coordinates
glide 1 secs to x: 100 y: 50 // Smooth movement over time
change x by 10 // Shift right by 10 pixels
point in direction 90 // Turn to face Right (0=Up, 180=Down)
Core Categories
Looks & Sound Blocks
Creating animation and audio effects for engaging projects.
Costumes & Speeches
next costume creates smooth walking/running animation frames. say [Hello!] for 2 secs displays speech bubbles.
Audio Triggers
play sound [Meow] until done pauses code execution until audio finishes playing before moving to the next block.
Event-Driven Paradigm
How Events Trigger Code
- Flag Click: Starts the main program loop.
- Key Press: Triggers character movement controls (e.g. Arrow keys).
- Sprite Click: Triggers interactive buttons or tap games.
- Backdrop Switch: Triggers stage transitions when changing game screens.
Movement Comparison
move 10 steps vs change x by 10
move 10 steps
Moves 10 pixels in whichever direction the sprite is currently facing (if facing left, it moves left!).
change x by 10
Moves 10 pixels strictly along the horizontal X axis to the right, regardless of sprite rotation angle.
Myth Buster
go to vs glide
❌ Teleporting Bug
Using go to x: 200 y: 0 inside a walking loop causes the sprite to flash instantly without smooth animation.
✅ Smooth Interpolation
Using glide 2 secs to x: 200 y: 0 calculates smooth step-by-step position updates across frames.
Smartboard Challenge
Coordinate Calculation Challenge
A sprite starts at origin (X: 0, Y: 0).
1. change x by 100
2. change y by -50
3. change x by -20
Solve on smartboard: What are the final (X, Y) coordinates of the sprite?
Smartboard Challenge
Identify the Block Type
Match each block description to its category shape:
1. when space key pressed
2. <touching [mouse-pointer]?>
3. (timer)
4. turn right 15 degrees
Match Options: Hat Block, Stack Block, Boolean Block, Reporter Block.
Program Logic
Top-to-Bottom Sequential Execution
STEP 1
Event Triggered
Hat block detects event click.
STEP 2
Reset State
Go to starting (X,Y) and set size 100%.
STEP 3
Execute Actions
Glide, switch costume, play audio sound.
STEP 4
Script End
Script finishes unless inside a loop.
Coding Activity
Building a Sprite Dance Routine
when green flag clicked
go to x: 0 y: 0
say "Let's Dance!" for 1 secs
next costume
play sound [Dance Beat] until done
glide 1 secs to x: 150 y: 100
Spot The Bug
Why does the Cat fly off screen forever?
when green flag clicked
set x to 500
move 10 steps
Debug Prompt: What is wrong with setting X to 500 on a 480-pixel wide stage?
Interactive Quiz · Question 1
What are the coordinates of the center point of the Scratch Stage?
A(X: 240, Y: 180)
B(X: 0, Y: 0)
C(X: -240, Y: -180)
D(X: 100, Y: 100)
Click to reveal answer
Interactive Quiz · Question 2
Which block shape MUST be at the very top of every executable script?
AReporter Block (Oval)
BBoolean Block (Hexagon)
CHat Block (Rounded Top)
DStack Block (Notched)
Click to reveal answer
Interactive Quiz · Question 3
If a sprite is at (X: 10, Y: 20) and executes change y by -30, what is its new Y position?
Click to reveal answer
Lesson Recap
Summary of Key Takeaways
- Stage Geometry: 480w x 360h grid with (0,0) at center.
- Block Types: Hat (events), Stack (actions), Boolean (conditions), Reporter (values).
- Execution: Sequential execution from top to bottom starting at a Hat block.
- Direction & Motion:
change x/y modifies specific coordinates independent of rotation.
Exit Ticket
Before You Leave
Write down in your notebook:
1. The exact coordinates to place a sprite in the Top-Left corner of the Scratch stage.
2. The difference between set x to 50 and change x by 50.
Next Chapter: Control Structures — Loops & Conditionals in Scratch!