CS 139 Algorithm Development
Lab01A: Getting started with Scratch


During the next few labs, you will be creating your own interactive computational media with Scratch. The concepts we learn in this environment translate directly to what you will be doing in Java throughout the semester.


The students will:

Key Terms

Sprite : a small being, human in form, playful and having magical powers

Materials Needed


Write the answers to the numbered questions in a text file or on a separate sheet of paper. You may be asked to share your answers with the rest of the class. Follow the steps below to create a Scratch project and experiment with it.

At the end of Parts 1 and 2, we will ask for volunteers to share what they have learned. You will submit your Scratch project electronically via Canvas at the end of the lab period.


This lab is adapted from the Scratch Curriculum Guide v20110923, released under the Creative Commons Attribution-ShareAlike license.


Part 1: Hello Scratch!

Step 1. What are some different ways you interact with computers?



Step 2. Which of those ways involve you creating something using computers?



Step 3. Watch the "Intro to Scratch" video at http://vimeo.com/29457909 (about 3 min).



Step 4. Using one of the lab computers, open the Scratch application.

When Scratch starts, you will see an application window with several parts: Note: In Scratch, there are more than 100 blocks in 8 different categories! We will only learn a subset of them in class, but you should feel free to explore all of them.


Step 5. To get started, let's make the cat do a dance. Start by dragging out the "move 10 steps" block from the "Motion" blocks palette to the scripting area. Every time you click on the block the cat moves a distance of 10.


Step 6. From the "Sound" palette, drag out the "play drum" block. Click on the block to hear its drum sound. Drag and snap the "play drum" block below the "move" block. When you click on this stack of two blocks, the cat will move and then play the drum sound.


Step 7. Copy this stack of blocks (either using the Duplicate toolbar item or by right-clicking the stack and selecting "duplicate") and snap the copy to the already-placed blocks.


Step 8. Go to the "Control" blocks palette and grab the "repeat" block. Wrap the "repeat" block around the other blocks in the scripting area. Now when you click on the stack, the cat dances forward and back 10 times.


Step 9. Finally, drag the "when Sprite clicked" block and snap it to the top of the stack. Click on the cat (instead of the blocks stack) to make the cat dance.


Step 10: Save your Scratch project in a safe place (e.g., thumb drive, Dropbox, Google Docs). Do not store it on the lab computer; it will be erased when you log out.


Part 2: About Me

Step 11. What are three aspects of yourself that you could represent through images or sound?


Step 12. For the rest of the lab, you are to design an interactive collage that represents these aspects. Refer to the "About Me" handout for details.

Tip: Check out the Scratch resource library at http://info.scratch.mit.edu/Support for the official getting started guide, video tutorials, scratch cards, and more. For other ideas, check out example projects at http://scratch.mit.edu/channel/featured.


Step 13. Questions to consider when finished: