Unit 2: The Internet

The goal of Unit 2 is for students to have a more concrete understanding of the Internet as a set of computers exchanging bits and the implications of these exchanges. Students use PHP and SQL to structure and access a database hosted on a remote server, learn how HTML and CSS direct the client computer to render a page, and experiment with JavaScript to provide dynamic content. The focus of the unit is on the protocols that allow the Internet to function securely to deliver social media and eCommerce content. Students work briefly in each of several Web languages to understand how the languages work together to deliver this content. The history and workings of the Internet are explored, and issues of security, privacy, and democracy are considered. Practical cyber security hygiene is included. Career paths in cyber security, web development, and information technology are highlighted.

2.1 The Internet and the Web

    • In this lesson, the goal is to build student understanding of the Internet as a set of computers exchanging bits in the form of packets. Students will learn to identify the components of their digital footprint. To provide a hook, students compare the designs, strengths, and weaknesses of their favorite web pages. In this context students use an unplugged activity to understand (in broad brushstrokes) the content and flow of data when browsing the Web. They compare results from different search engines and learn to refine their search techniques. They review how to assess the trustworthiness of web-based media and consider the data flow that permits targeted advertisements. Students employ appropriate tools to explore the hierarchical nature of DNS and IP. Students identify ways that a web developer’s decisions affect the user and ways that the user’s decisions impact society. The tree structure of web documents is introduced alongside HTML and CSS. Paired key encryption and authentication are introduced with an unplugged activity.

2.2 Shopping and Social on the Web

    • The goal for this lesson is for students to understand the role of client-side code, server-side code, and databases in delivering interactive web content. The hook is a problem in which CS students collaborate with art students to publish content on the Web. Students are provided with JavaScript and PHP code and can access an SQL database from a secure shell command line as well as through PHP. Students compare languages encountered so far to generalize the concepts of sequencing instructions, selection of instructions by conditionals, iteration, and the common roles of variables. Students explore and compare career paths within computing.

2.3 Security and Cryptography

    • The goal of this lesson is for students to personally invest in maintaining online security and to improve their personal cyber security hygiene. Students focus on cyber security from the perspectives of the user, the software developer, the business, the nation, and the citizen. In the team competition at the end of the lesson, students explore parallel strands in encryption and security. Encryption is used as a route to explore the efficiency of algorithms and how the time for an algorithm to execute can be dependent on its input.