Preface

When we program, we solve problems. In order to solve problems, we think, take action, and reflect upon our efforts. Scratch teaches us to program using a fun, accessible environment that's as easy as dragging and dropping blocks from one part of the screen to another.

In this book, we will program games, stories, and animations using hands-on examples that get us thinking and tinkering. For each project, we start with a series of steps to build something. Then, we pause to put our actions into context so that we can relate our code to the actions on Scratch's stage. Throughout each chapter, you'll encounter challenges that encourage you to experiment and learn.

As you begin working through the examples in the book, you won't be able to stop your imagination, and the ideas will stream as fast as you can think of them. Write them down. You'll quickly realize there are a lot of young minds in your home, classroom, or community group that could benefit from Scratch's friendly face. Teach them, please.

What this book covers

Chapter 1 provides an overview of Scratch, its features, and how it can help you teach 21^st century learning skills to your children and students.

Chapter 2 guides us through the installation of Scratch on Windows, OS X, and Linux. This chapter also helps you run the Scratch programming environment from a USB flash drive.

Chapter 3 explores the Scratch interface and allows us to create some simple scripts that demonstrate how easily we can build a project. This is a high-speed tour of Scratch that gets us tinkering and thinking about what's possible.

Chapter 4 teaches us how to create an animated birthday card and a slideshow of our favorite photos.

Chapter 5 allows us to horse around as we develop a barnyard humor book that lets us narrate multiple scenes. There's no need to hold the applause.

Chapter 6 takes a classic pong game and gives it a little personality by adding a troll, switching levels, and keeping score.

Chapter 7 takes us to the fortune-teller, but before we learn the random answers to all our deepest questions, we must create our game using the Magic 8 ball's fortunes.

Chapter 8 uses mathematical formulas and graphs to help us answer the question, "Would you rather have a dollar that doubles every day or a lump sum of money?" The answer may surprise you.

Chapter 9 explains how to share your project with the Scratch community and how to promote it to you friends and fans.

Chapter 10shows us how to connect a webcam and an external sensor board to our computer and delivers real-world stimuli as input to Scratch projects.

What you need for this book

All you need is an imagination and a willingness to experiment. You will also need a computer with Scratch 1.4 installed. Most modern computers should easily run the latest version of Scratch; however, the Scratch team makes Scratch 1.2.1 available on the Scratch Download page for older systems. Here are the system requirements as defined by the Scratch team:

Display: 1024 x 768

16-bit color or higher

Disk Space: At least 120 MB

Operating Systems:

• Windows 2000 or higher for Scratch 1.3

• Windows 98 users can use Scratch 1.2.1

• Mac OS X 10.4 for Scratch 1.3

• Mac OS X 10.3 for Scratch 1.2.1

• Linux support via WINE

• Native Linux support is experimental

If you want to take advantage of Scratch's audio and recording features, you will need a sound card, speakers, and a microphone.

Who this book is for

Scratch is a teaching language, so it's ideal for people who want to learn how to program or teach others how to program. Educators and parents will learn how to program using Scratch, and they can use Scratch to teach 21^st century learning skills to their students and children.

The 21^st century learning skills help develop digital literacy by teaching children how to design, think critically, collaborate, communicate, and program in a computer language.

No previous computer programming knowledge is required. If you know how to send email, create documents, or create presentations, then you have the prerequisite skills to learn how to program in Scratch.

For beginning programmers, this book will teach the basic concepts that you can then utilize to learn more advanced languages, such as Ruby, PHP, and Python.

Parents, are you stuck with a child who wants to play video games all night? Make a new rule. Your child can play a video game only if he or she programs the game first.

Conventions

In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, along with an explanation of their meaning:

Code words in text are shown as follows: "We can include other contexts through the use of the include directive."

New terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes for example, appear in our text like this: "Clicking the Next button moves you to the next screen."

Note

Warnings or important notes appear in a box like this.

Tip

Tips and tricks appear like this.

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