Scratch Programming – The 3S of Scratch Basic 6 Basic Technology Lesson Note

Learning Objectives

By the end of the lesson, pupils should be able to:

• Identify the component parts of the scratch interface
• Differentiate between the 3S of Scratch

Content

What is Scratch? Scratch is a visual programming language designed for children and beginners. It uses blocks that snap together like puzzle pieces to create programs, games, and animations.

Opening Scratch

• Online: Go to scratch.mit.edu
• Offline: Install Scratch desktop application

Parts of the Scratch Interface

1. Stage (Top Right)

• Where your projects come to life
• Shows sprites performing actions
• Default size: 480 × 360 pixels
• Has x and y coordinates

2. Sprite Area (Bottom Right)

• Shows all sprites in your project
• Default sprite is Scratch Cat
• Can add, delete, or modify sprites

3. Backdrop Area

• Next to sprite area
• Shows background of stage
• Can change or create backdrops

4. Block Palette (Left Side)

• Contains all coding blocks
• Organized by categories with colors
• Drag blocks to Scripts Area

5. Scripts Area (Middle)

• Where you build your code
• Drag and connect blocks here
• Shows your program

6. Code/Costumes/Sounds Tabs (Top Middle)

• Code: Write programs
• Costumes: Change sprite appearance
• Sounds: Add sounds to sprites

The 3S of Scratch

The 3S refers to the three main elements you work with in Scratch:

1. SPRITES

• Definition: Characters or objects in your project 
• Examples: Animals, people, objects, shapes 
• Features: 
  1. Can move around the stage
  2. Can change appearance (costumes)
  3. Can interact with other sprites
  4. Have properties (position, size, direction)
• Creating Sprites: 
  1. Choose from library
  2. Paint your own
  3. Upload from computer
  4. Take photo with camera
• Sprite Properties: 
  1. Position (x, y coordinates)
  2. Direction (which way it faces)
  3. Size (can make bigger or smaller)
  4. Visibility (show or hide)

2. SCRIPTS

• Definition: Programs made by connecting code blocks 
• Purpose: Tell sprites what to do 
• Features: 
  1. Made by stacking blocks vertically
  2. Blocks snap together like Lego
  3. Different colors for different functions
  4. Run from top to bottom
• Block Categories: 
  1. Motion (blue): Move, turn, position
  2. Looks (purple): Appearance, speech
  3. Sound (pink): Play sounds, music
  4. Events (yellow): Start programs
  5. Control (orange): Loops, conditions
  6. Sensing (light blue): Detect things
  7. Operators (green): Math, logic
  8. Variables (orange): Store data

Example Simple Script:

When green flag clicked

Move 10 steps

Say “Hello!” for 2 seconds

3. STAGE

• Definition: The background/scene where sprites perform 
• Size: 480 pixels wide × 360 pixels tall 
• Features: 
  1. Has coordinate system (x: -240 to 240, y: -180 to 180)
  2. Center is (0, 0)
  3. Can have different backdrops
  4. Can have its own scripts
• Stage Coordinates: 
  1. Center: (0, 0)
  2. Top: y = 180
  3. Bottom: y = -180
  4. Right: x = 240
  5. Left: x = -240
• Backdrops: 
  1. Can change for different scenes
  2. Can be animated
  3. Created or chosen from library

How the 3S Work Together

1. Sprites are the actors
2. Scripts are the instructions
3. Stage is where everything happens

Example: A sprite (cat) follows a script (move and meow) on the stage (with a garden backdrop).

Scratch Project Workflow

1. Choose or create sprites
2. Select or create backdrop
3. Write scripts for sprites
4. Test your project (click green flag)
5. Debug (fix problems)
6. Share or save

Activities

• Explore Scratch interface online
• Identify all parts of the interface
• Add and delete sprites
• Change backdrops
• Create a simple script to make sprite move
• Experiment with different blocks