Joshi - Practice CS Concepts with Scratch

Preface

We must be very careful when we give advice to younger people; sometimes they follow it!

Edsger W. Dijkstra

This book is a supplement to the book titled Learn CS Concepts with Scratch by the same author. It provides additional review questions to evaluate your understanding of CS concepts, and additional programming assignments to practice all these concepts.

The idea of using computer programming as a medium for learning is rapidly gaining acceptance. The benefits of learning programming and computer science concepts well before college even in elementary grades are well-understood.

Here is a list of some of the amazing things that happen when children and young adults engage in computer programming:

• They become active and creative learners, because they explore ideas through a hands-on activity with an infinitely powerful tool.
• They learn to think about and analyze their own thinking , because that is the only way to program computers.
• They learn to solve complex problems by breaking them into smaller sub-problems.
• They learn a new way of thinking (called "computational" thinking).
• In the world of programming, answers are not simply "right" or "wrong"; this prepares a student's mindset for real-life problems.
• The learning process is transformed from acquiring facts to thinking creatively and analytically .

The book is organized exactly along the lines of the original book: as a series of units each containing a bunch of CS concepts and associated programming activities. Every programming assignment requires understanding of all the concepts presented in the current as well as all preceding units.

Answers to all review questions and links to working programs for most of the programming exercises in the book are available online. Download them at: http://www.abhayjoshi.net/spark/scratch/book0s/solutions.pdf .

This book is designed to work with Scratch version 2. Download Scratch 2 editor at: https://scratch.mit.edu/download/scratch2 . The Scratch offline editor works on all Windows, Linux, and Mac computers.

You could also work online by creating your own account at http://scratch.mit.edu which runs Scratch Version 3. Although Version 3 may appear quite different compared to Scratch Version 2, it includes all the features required for the assignments in this book, and your program behavior (look and feel) would be identical on both versions.

Acknowledgements

Most of the material used for this book came from my teaching experience of the last several years. I would like to thank Aksharnandan School in Pune for allowing me to teach Scratch to their students every year (since 2008) during my summer visits to Pune. I wish to thank my 1000+ students in India and USA. They tolerated my ideas, contributed their own, and frankly told me what was interesting and what wasnt. Their projects were amazingly creative which only reinforced my belief that teaching programming is a good idea!

I wish to thank Tanuja Joshi for reviewing the material of this book diligently and tirelessly and for providing me with valuable suggestions. I wish to thank Ravindra Pande for creating a truly beautiful cover for the book.

Finally, this book would not have been possible without the constant encouragement of my friends and family.

I do hope that you will find this book useful and enjoyable.

Abhay B. Joshi ( )

Seattle, USA

1 June 2019

Authors background

As a freelance teacher, Abhays area of interest is teaching Computer Programming as "the exciting new magic" and also as a "medium for learning" in the constructivist tradition. He has been teaching regularly to elementary, middle, and high school students in WA, USA and Pune, India since 2008. He teaches at Aksharnandan School in Pune, India every summer, and works with TEALS (http://tealsk12.org/) to teach Computer Science to high school students in the US. Abhay teaches both in person and over the Internet using video-conferencing tools. Since 2011, he has authored or co-authored several programming books, which are based on Scratch, Snap, and Logo. He has written several articles to promote CS education, and offers teacher-training workshops to encourage aspiring teachers to experiment with this idea.

Abhay has been associated with the Software Industry since 1988 as a programmer, product developer, entrepreneur, and teacher. After getting an MS in Computer Engineering from Syracuse University (USA), he worked as a software engineer for product companies that developed operating systems, network protocols, and secure software. In 1997, Abhay co-founded Disha Technologies, which grew to be a successful software services organization.

Programming remains one of Abhays favorite hobbies, and he continues to explore the entertaining, intellectual, and educational aspects of programming.

Creative activities bring joy, meaning, and purpose to peoples lives. Focusing on creativity is not just an economic imperative, it is also a path towards human fulfillment, an opportunity for humans to be more human. Mitchel Resnick, MIT

Contents

Learning to program can change the way children learn everything else. Seymour Papert

The purpose of this unit is only to explain to you the format of each subsequent Unit in this book. Each Unit will contain sections listed below.

In this section, we list the Scratch and CS concepts relevant to this Unit. The review questions and programming assignments are based on these concepts and on those covered in all previous Units.

In this section, you will find questions that will help you review your understanding of the concepts learnt thus far. This understanding is necessary before you go about solving the programming assignments that follow.

In this section, you will find programming problems that will help you practice your understanding of all the Scratch and CS concepts you have learnt in this Unit and all the preceding Units.

Appendix A provides two pieces of information that may come handy when you tackle these programming assignments:

One is links to demo videos that demonstrate the behavior of each program. Of course, these are only sample demos, and you can be totally creative with your own programs. The other is a file that tells you which Scratch/CS concepts are relevant for each program.