What Scratch Is and How Code Blocks Work

Welcome to the world of making games! Scratch is a free programming language made by the MIT Media Lab. In Scratch you do not type long code. You snap together coloured blocks that lock into each other, much like building with LEGO pieces.

A program is like a teacher's instruction

Imagine the school bell rings at your school. The class captain then calls out: "Stand up, greet the teacher!" Every student stands and says good morning. That is a program: there is a trigger (the bell rings) followed by a sequence of commands carried out one by one from top to bottom.

In Scratch, a chain of connected blocks is called a script. For example:

when green flag clicked
say Hello! for 2 seconds
move 10 steps

The first block is the trigger. The two blocks below it run in order after the green flag is clicked.

Three important words

• Sprite: a character or object you can program, such as the Scratch Cat.
• Stage: the place where sprites perform, at the top right of the screen.
• Script: a stack of blocks that gives commands to a sprite.

The parts of the Scratch 3 screen

1. The block palette on the left, grouped by colour: Motion (blue), Looks (purple), Sound (pink), Events (yellow), Control (orange), and more.
2. The code area in the middle, where you build with blocks.
3. The stage at the top right, with the green flag button to run and the red stop sign to stop.
4. The sprite list below the stage, to select or add sprites.

You can open Scratch on the website scratch.mit.edu or with the Scratch app, which works without the internet. If you prefer Indonesian, click the globe icon in the top menu bar and choose Bahasa Indonesia. In this course the English lessons use the English block names, so the menus will match if your Scratch is set to English.

For parents or teachers: help the child when creating a Scratch account, because an account needs an adult's email address.