Scratch 3.0 Block Reference

Scratch 3.0 Block Reference 📚

This comprehensive reference covers every block in Scratch 3.0, organized by category with practical examples and common use cases. Perfect for quick lookups during project development!

🔵 Motion Blocks

Motion blocks control how sprites move and position themselves on the stage.

Moving Around

move (10) steps

Moves sprite forward in its current direction
Negative numbers move backward
Example: move (-5) steps moves 5 steps backward

turn ↻ (15) degrees / turn ↺ (15) degrees

Rotates sprite clockwise (↻) or counter-clockwise (↺)
90 degrees = quarter turn, 180 degrees = half turn
Example: turn ↻ (90) degrees faces sprite to the right

point in direction (90)

Sets sprite to face specific direction
0° = up, 90° = right, 180° = down, 270° = left
Example: point in direction (0) makes sprite face up

point towards (mouse-pointer ▼)

Aims sprite at mouse pointer or another sprite
Perfect for following cursors or chasing games
Example: Enemy sprites pointing toward player

Exact Placement

go to x:(0) y:(0)

Moves sprite to exact coordinates instantly
Stage center is (0, 0)
Example: go to x:(200) y:(100) moves to upper right area

go to (mouse-pointer ▼)

Instantly moves sprite to mouse or another sprite
Useful for teleportation effects
Example: Collectible items following the cursor

glide (1) secs to x:(0) y:(0)

Smoothly moves sprite over time
Creates elegant movement animations
Example: glide (2) secs to x:(100) y:(50) for smooth transitions

change x by (10) / change y by (10)

Adjusts position by specific amounts
Positive x = right, negative x = left
Positive y = up, negative y = down

set x to (0) / set y to (0)

Sets exact x or y coordinate
Useful for keeping sprites on specific paths
Example: set y to (0) keeps sprite on horizontal center line

Staying on Stage

if on edge, bounce

Automatically reverses direction at stage edges
Essential for ball games and bouncing objects
Sprite continues moving but changes direction

set rotation style (left-right only ▼)

Controls how sprite looks when it rotates
all around: Sprite rotates freely (like a spinning top)
left-right only: Sprite flips but stays upright (like walking character)
don’t rotate: Sprite never changes appearance when turning

Position Information (Reporter Blocks)

x position / y position

Returns current sprite coordinates
Useful for conditional statements and calculations
Example: if <(x position) > (200)> then (if sprite is far right)

direction

Returns sprite’s current facing direction (0-360 degrees)
Useful for complex movement calculations
Example: Checking if sprite is facing generally upward

Motion Block Use Cases

🏃‍♀️ Character Movement

Use arrow key controls with change x by and change y by for player-controlled characters.

⚽ Ball Physics

Combine move steps, if on edge, bounce, and turn degrees for realistic ball movement.

🌟 Following Effects

Use point towards and move steps to create enemies that chase the player.

🎯 Precise Animations

Use glide blocks for smooth, timed movements between specific positions.

🟣 Looks Blocks

Looks blocks control sprite appearance, visibility, and visual effects.

Speech and Thought

say [Hello!] for (2) seconds

Shows speech bubble with text
Bubble automatically disappears after time
Example: Character greetings and dialogue

say [Hello!]

Shows speech bubble that stays until changed
Must be manually cleared with empty say block
Example: Permanent status displays

think [Hmm...] for (2) seconds / think [Hmm...]

Similar to say blocks but uses thought bubble
Cloudier appearance for internal thoughts
Example: Character planning or reacting

Displaying Information

Use join operator to combine text: say (join [Score: ] (score))
Display variable values: say (player_name) for (3) seconds
Create dynamic messages based on game state

Changing Appearance

switch costume to (costume1 ▼)

Changes to specific costume instantly
Essential for character animation
Example: Switching to “jumping” costume when space pressed

next costume

Cycles through costumes in order
Creates automatic animation loops
Example: Walking animation by changing costumes repeatedly

switch backdrop to (backdrop1 ▼) / next backdrop

Changes stage background (only works on stage)
Use for scene changes and level progression
Example: Different backdrops for different game levels

Animation Techniques

// Walking animation
forever
  next costume
  wait (0.2) seconds

// Smooth costume cycling
repeat until <(costume number) = (5)>
  next costume
  wait (0.1) seconds

Size and Visibility

change size by (10) / set size to (100) %

Grows or shrinks sprite appearance
100% = normal size, 50% = half size, 200% = double size
Example: Power-up effects or zoom animations

show / hide

Makes sprite visible or invisible
Hidden sprites still run scripts and can interact
Example: Hiding collectibles after they’re collected

go to (front ▼) layer / go (forward ▼) (1) layers

Controls which sprites appear in front of others
front: Moves to very front
back: Moves to very back
forward/backward: Moves specific number of layers

Color and Effects

change [color ▼] effect by (25)

Applies visual filters to sprites
color: Shifts hue (rainbow effect)
fisheye: Bulges appearance
whirl: Swirls the sprite
pixelate: Makes sprite blocky
mosaic: Creates tiled effect
brightness: Lightens or darkens
ghost: Makes transparent

set [color ▼] effect to (50)

Sets effect to specific value instead of changing
Use negative numbers to reverse effects
Example: set [ghost ▼] effect to (50) makes sprite 50% transparent

clear graphic effects

Removes all visual effects, returning sprite to normal
Essential for resetting appearance

Looks Block Use Cases

🎭 Character Animation

Use costume changes with timing to create walking, running, or flying animations.

💬 Interactive Dialogue

Combine say blocks with ask blocks for conversation systems in stories and games.

✨ Special Effects

Use graphic effects for power-ups, damage indicators, or magical transformations.

🎬 Scene Management

Use backdrop changes and layer controls to create cinematic experiences.

🟡 Sound Blocks

Sound blocks add audio to your projects, from simple sound effects to complex musical compositions.

Basic Audio

play sound (meow ▼) until done

Plays sound completely before continuing script
Blocks other actions until sound finishes
Example: Character voice lines that must complete

start sound (meow ▼)

Starts sound but continues script immediately
Allows sounds to overlap and play simultaneously
Example: Background music while other sounds play

stop all sounds

Immediately stops all audio
Useful for scene transitions or pause functionality
Example: Stopping music when game ends

Sound Library

Scratch includes categories of sounds:

Animal: Cat meow, dog bark, bird chirp
Effects: Pop, boing, whoosh, laser
Human: Applause, laughter, footsteps
Instrumental: Piano, guitar, drums, electronic
Musical: Complete songs and melodies

Musical Notes

play note (60) for (0.5) beats

Plays specific musical note
Note 60 = Middle C, each number is one semitone
Beat length: 0.25 = sixteenth note, 0.5 = eighth note, 1 = quarter note

rest for (0.5) beats

Creates silence for specified duration
Essential for rhythm and musical spacing
Example: Creating pauses in melodies

set instrument to (1) Piano

Changes the sound of played notes
21 different instruments available
Example: Switch to drums (instrument 9) for percussion

Musical Examples

// Simple melody
set instrument to (1) Piano
play note (60) for (1) beats  // C
play note (62) for (1) beats  // D
play note (64) for (1) beats  // E
play note (60) for (2) beats  // C (longer)

// Drum beat
set instrument to (9) Drums
repeat (4)
  play note (36) for (0.5) beats  // Kick drum
  rest for (0.5) beats

Volume and Effects

change volume by (-10) / set volume to (50)

Controls how loud sounds play
Volume range: 0 (silent) to 100 (loudest)
Example: Fading music by gradually decreasing volume

change [pitch ▼] effect by (10) / set [pitch ▼] effect to (50)

pitch: Higher numbers = higher pitch, lower = deeper
pan left/right: Controls left/right speaker balance
Example: Higher pitch for excitement, lower for danger

clear sound effects

Resets all audio effects to normal
Useful after applying temporary sound modifications

Reporter Blocks

volume

Returns current volume level (0-100)
Useful for conditional sound effects
Example: Only play sound if volume is above 10

Advanced Audio Techniques

// Fade out effect
repeat (10)
  change volume by (-10)
  wait (0.1) seconds

// Dynamic sound effects
if <(score) > (100)> then
  set [pitch ▼] effect to (20)  // Victory sound higher pitch
else
  set [pitch ▼] effect to (-10) // Normal sound lower pitch

Sound Block Use Cases

🎮 Game Audio

Layer background music, sound effects, and UI sounds for immersive gaming experiences.

🎵 Music Composition

Create original songs using note blocks and different instruments.

📚 Audio Stories

Add narration, character voices, and sound effects to interactive stories.

🔔 Feedback Systems

Use sounds to provide immediate feedback for user actions and game events.

🟠 Events Blocks

Events blocks determine when scripts start running - they’re the triggers that make everything happen.

Initialization Events

when green flag clicked

Most common way to start programs
Runs when user clicks the green flag above the stage
Use for game setup, variable initialization, and main program loops

when this sprite clicked

Runs when user clicks on the specific sprite
Each sprite can have its own click handler
Example: Interactive buttons, clickable characters

when stage clicked

Runs when user clicks on empty stage area (not on a sprite)
Only available for stage scripts
Example: Hiding menus when clicking away from them

Program Examples

// Game initialization
when green flag clicked
set [score ▼] to (0)
set [lives ▼] to (3)
go to x:(0) y:(0)
show

// Interactive sprite
when this sprite clicked
say [You clicked me!] for (2) seconds
change [clicks ▼] by (1)

Key Press Events

when [space ▼] key pressed

Runs once each time the specified key is pressed
Available for all letters, numbers, and special keys
Example: Space bar for jumping, arrow keys for movement

Common Key Combinations

Arrow keys: Character movement controls
Space bar: Jump, shoot, or primary action
Enter: Confirm selections or advance dialogue
Letters: Quick access to different functions (R for restart, P for pause)

Input Handling Examples

// Jump character
when [space ▼] key pressed
if <touching (ground ▼)?> then
  change y by (50)
  play sound (jump ▼) until done
end

// Pause game
when [p ▼] key pressed
if <(game_paused) = (0)> then
  set [game_paused ▼] to (1)
  say [PAUSED] for (9999) seconds
else
  set [game_paused ▼] to (0)
  say []  // Clear pause message
end

Broadcasting Events

broadcast (message1 ▼)

Sends a message that all sprites can receive
Continues script immediately after sending
Example: Signaling level completion or game events

broadcast (message1 ▼) and wait

Sends message and waits for all receiving scripts to finish
Ensures coordination between sprites
Example: Waiting for all enemies to finish their death animations

when I receive (message1 ▼)

Runs when the specified message is broadcast
Multiple sprites can respond to the same message
Example: All enemies responding to “start level” message

Communication Examples

// Game controller sprite
when green flag clicked
wait (3) seconds
say [Ready?] for (2) seconds
broadcast (start game ▼)

// Player sprite
when I receive (start game ▼)
forever
  // Game controls here

// Coordinated animation
when [enter ▼] key pressed
broadcast (dance party ▼) and wait
say [What a show!] for (3) seconds

// Multiple sprites
when I receive (dance party ▼)
repeat (10)
  turn ↻ (36) degrees
  wait (0.1) seconds

Sensor-Based Events

when [loudness ▼] > (10)

Responds to microphone input
Loudness scale: 0 (silent) to 100 (very loud)
Example: Clap-controlled games or voice activation

when [timer ▼] > (10)

Triggers when timer reaches specific value
Timer starts at 0 when green flag clicked
Example: Time-based events or automatic level progression

when backdrop switches to (backdrop1 ▼)

Runs when stage background changes
Only available for sprite scripts (not stage)
Example: Character reactions to scene changes

Advanced Event Examples

// Voice-controlled sprite
when [loudness ▼] > (20)
say [I heard you!] for (1) seconds
change size by (10)
wait (1) seconds
change size by (-10)

// Timed level progression
when [timer ▼] > (60)
say [Time for the next level!] for (2) seconds
broadcast (next level ▼)
reset timer

Clone Events

when I start as a clone

Runs immediately when a clone is created
Each clone runs this script independently
Example: Setting unique properties for each clone

// Clone initialization
when I start as a clone
go to (random position ▼)
set [my speed ▼] to (pick random (1) to (5))
show

forever
  move (my speed) steps
  if on edge, bounce

Events Block Use Cases

🎮 Game Controls

Map keyboard inputs to character actions for responsive game controls.

📡 Sprite Communication

Use broadcast messages to coordinate complex interactions between multiple sprites.

🎭 Interactive Experiences

Respond to clicks, voice, and other inputs for engaging user interactions.

⏰ Timed Events

Create automatic progressions, countdowns, and time-based gameplay elements.

Quick Reference Tips 💡

Block Shapes Remember

Hat blocks (rounded top): Start scripts
Stack blocks (rectangular): Actions and commands
Boolean blocks (hexagonal): True/false questions
Reporter blocks (rounded): Values and information
Cap blocks (flat bottom): End scripts

Common Patterns

Game loop: when green flag clicked → forever loop
Player input: when [key] pressed → movement/action
Collision: if <touching [sprite]?> then → response
Animation: repeat loop with next costume and wait

🎯 Block Categories Deep Dive Explore Control, Sensing, Operators, Variables, and Custom Blocks with detailed examples.

This reference guide grows with your programming journey. Bookmark it and return whenever you need quick help with specific blocks or techniques! 📚✨