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Unit 2

Introduction to Mobile Apps & Pair Programming

2.1 Unit Overview

2.2 I Have a Dream Tutorial

2.3 The Internet & The Cloud

2.4 I Have a Dream Part 2

2.5 Mobile Apps & Devices

2.6 Algorithm Basics

2.7 I Have a Dream Projects

2.8 Abstraction

2.9 Binary Numbers

2.10 Hardware Abstractions: Logic Gates

2.11 The Digitial Explosion

2.12 Wrap Up


The Internet and the Cloud

The Internet is one of the 7 Big Ideas of the CS Principles curriculum. This course focuses on three key questions about the Internet:

  • What is the Internet, how is it built, and how does it work?
  • What aspects of the Internet design and development have enabled it to grow so large and be so influential?
  • How does cybersecurity affect what we do on the Internet?

The Internet and the World Wide Web have had a tremendous influence on our world and our lives. Yet, most people do not really understand what the Internet is and how it works. This lesson provides a high-level overview of some key concepts and clarifies the difference between the Internet and the World Wide Web (WWW). Lessons later in the course will go into greater detail in explaining how the Internet works.


Let's begin with a common misconception. Most people do not distinguish between the Internet and the World Wide Web, but they are two completely different things. The basic distinction is this: