Introduction to Scratch Programming

Posted on by firefly

Scratch is a programming language based on dragging and dropping different blocks. This means you can explore and start programming without the hassle of fixing typos and syntax errors.

Scratch programming is all done in the web browser, at scratch.mit.edu. The Scratch website includes its own tools for creating and modifying graphics, sounds and music — everything you need to create a fun and unique program.

A couple important elements in Scratch that you’ll see in almost every program. The first is your sprite, you’ll see when you first open up Scratch there’s a little Scratch cat on the top right. This is the default sprite for Scratch, you can add more from their library, from uploads, or from the paint program that’s right inside Scratch! All of the code in the center part of you screen is tied to this sprite. You can also add more sprites with their own code.

You’ll also notice a green flag and a stop sign. The stop sign is pretty straightforward; it stops whatever code is running. The green flag, however, only has an effect if you use the event “when green flag is clicked”. You’ll find this event in most Scratch programs.

For our most basic program, the “Hello World” program, we’ll use the green flag event and drag that into the center of the screen. Then we’ll need to go to the Looks category and find one that says “say Hello! for 2 seconds”. Notice that this block has a particular shape that we can attach it to our green flag event. Then we can change the default “Hello!” message to say “Hello World!”

Try it out! Click the green flag and see the Scratch cat offer you a greeting, then check our more lessons.