12 KiB
12 KiB
Weeks 15–16: Networks, Email, and the Web
Hours: 4 (2 lectures)
Learning Objectives
- Explain what a computer network is and why they exist
- Describe the basic components of a network (routers, switches, modems, access points)
- Distinguish between LAN, WAN, and the Internet
- Explain how the Internet works at a high level (IP addresses, DNS, HTTP/HTTPS)
- Use email effectively and professionally
- Navigate the web with understanding (URLs, browsers, search engines)
- Evaluate online information for credibility
Lecture 15: Networks & the Internet
Key Concepts
What Is a Network? Two or more devices connected to share resources and communicate.
💡 Analogy: A network is like a postal system. Every device has an address. Routers are like post offices — they figure out where to send things. Cables (or Wi-Fi) are the roads.
Types of Networks
| Type | Scope | Example |
|---|---|---|
| PAN (Personal Area Network) | Within reach of a person | Bluetooth earbuds ↔ phone |
| LAN (Local Area Network) | One building or campus | Home Wi-Fi, office network |
| WAN (Wide Area Network) | Multiple locations, large area | Company offices across cities |
| The Internet | Global | Worldwide network of networks |
Network Hardware
- Modem: Connects your home network to your ISP (Internet Service Provider). Translates signals.
- Router: Directs traffic between devices and between your network and the Internet. Assigns local IP addresses.
- Switch: Connects multiple devices on a LAN. Smarter than a hub — sends data only where it needs to go.
- Wireless Access Point (WAP): Provides Wi-Fi connectivity.
- NIC (Network Interface Card): Hardware in your device that connects to the network (built-in on modern devices).
- Ethernet Cable (RJ-45): Wired connection. Faster and more reliable than Wi-Fi.
💡 Home network walkthrough: "At home, your ISP brings the Internet to your modem. The modem connects to your router. Your router creates your home network and shares the Internet with your devices via Wi-Fi or Ethernet."
How the Internet Works
- IP Address: A unique address for every device on a network (like a street address)
- IPv4: 192.168.1.1 (four numbers, 0-255)
- IPv6: Longer format for the modern era (we ran out of IPv4 addresses)
- Public IP (your home's address to the world) vs Private IP (each device inside your home)
- DNS (Domain Name System): Translates human-readable names to IP addresses
- You type
google.com→ DNS looks up142.250.80.46→ your browser connects - DNS = "the phone book of the Internet"
- You type
- HTTP / HTTPS: Protocol for transferring web pages
- HTTP = unencrypted (anyone can read the data in transit)
- HTTPS = encrypted with SSL/TLS (look for the padlock 🔒)
- Always look for HTTPS on login pages and when entering personal info
How Data Travels: Packets
- Data is broken into small packets
- Each packet is labeled with source and destination addresses
- Packets may take different routes and are reassembled at the destination
- Protocols (TCP/IP) ensure all packets arrive and are in the right order
💡 Analogy: Sending a large book by mail. You tear out each page, put it in a separate envelope with a page number, and mail them. Some might go through different post offices. The receiver puts them back in order.
Wired vs Wireless
| Feature | Wired (Ethernet) | Wireless (Wi-Fi) |
|---|---|---|
| Speed | Faster (up to 10 Gbps) | Slower (varies, typically 100-1000 Mbps) |
| Reliability | More stable | Can have interference |
| Mobility | Fixed location | Move freely |
| Security | Harder to intercept | Needs encryption (WPA3) |
| Setup | Cables required | No cables |
Diagram Ideas
- Home Network Diagram — ISP → Modem → Router → (Wi-Fi to laptop, phone, tablet) + (Ethernet to desktop, smart TV). Label each component.
- How DNS Works — Flow: User types URL → Browser asks DNS → DNS returns IP → Browser connects to server → Page loads.
- Data Packets Journey — Illustration: Message split into packets, each taking different paths, reassembled at destination.
- LAN vs WAN vs Internet — Nested circles: PAN inside LAN inside WAN inside Internet.
Slide Concepts
| Slide | Content |
|---|---|
| 1 | Title: "Connected: Networks & the Internet" |
| 2 | What Is a Network? — definition + postal analogy |
| 3 | Types: PAN → LAN → WAN → Internet |
| 4 | Network Hardware — labeled home network diagram |
| 5 | IP Addresses — your device's address |
| 6 | DNS — the Internet's phone book |
| 7 | HTTP vs HTTPS — the padlock matters |
| 8 | How Data Travels — packets explained |
| 9 | Wired vs Wireless — comparison |
Lecture 16: Email & the World Wide Web
Key Concepts
Email Fundamentals
- Email address format: username@domain.com
- Protocols: SMTP (sending), IMAP/POP3 (receiving) — mention briefly, don't belabor
- Components of an email:
- To: Primary recipient(s)
- CC: Carbon copy — others who should see it
- BCC: Blind carbon copy — hidden recipients
- Subject: Brief, descriptive summary
- Body: The message
- Attachments: Files sent with the email
- Signature: Auto-appended closing info (name, title, contact)
Professional Email Etiquette
- Use a clear, specific subject line (not "Hi" or "Question")
- Address the recipient appropriately
- Be concise and use proper grammar
- Don't use ALL CAPS (reads as shouting)
- Be careful with Reply All — does everyone need to see your response?
- Review before sending (especially attachments — are they actually attached?)
- BCC for mass emails to protect recipients' privacy
- Don't forward chain emails, jokes, or unverified information
💡 Teaching idea: Show two versions of the same email — one casual/sloppy, one professional. Which would you trust? Which would get a response?
Managing Email
- Inbox Zero concept: process, respond, archive, or delete
- Folders/Labels for organization
- Stars/Flags for follow-up
- Spam/Junk: what it is, how filters work, why you shouldn't click links in suspicious emails
The World Wide Web
- The Web ≠ the Internet. The Internet is the infrastructure. The Web is a service that runs on it (like email, streaming, gaming).
- Web Browser: Software for viewing web pages (Chrome, Firefox, Edge, Safari)
- URL (Uniform Resource Locator): The address of a web page
https://www.gavilan.edu/academic/csis/index.php- Protocol → Domain → Path
- Search Engine: Tool for finding information (Google, Bing, DuckDuckGo)
- Search engines ≠ the Internet. They're a tool for finding things on it.
Evaluating Online Information (CRAAP Test)
| Criterion | Question to Ask |
|---|---|
| Currency | When was this published or updated? |
| Relevance | Does this relate to my topic? |
| Authority | Who wrote it? Are they credible? |
| Accuracy | Is it supported by evidence? Can you verify it elsewhere? |
| Purpose | Why does this exist? To inform, sell, persuade, entertain? |
💡 Activity: Give students 3 sources on the same topic — a peer-reviewed article, a blog post, and a satirical news article. Have them evaluate each using the CRAAP test.
Web 2.0 & Cloud Services
- Social media, wikis, blogs, user-generated content
- Cloud applications: Google Docs, Microsoft 365 online, Canva
- Collaboration: real-time editing, sharing, commenting
Diagram Ideas
- Email Anatomy — Labeled email showing To, CC, BCC, Subject, Body, Attachment icon, Signature.
- URL Breakdown —
https://www.example.com/products/shoes.htmlwith labeled parts: protocol, subdomain, domain, path, page. - Internet vs Web — Venn-style: Internet = infrastructure (email, gaming, streaming, web). Web = one service on the Internet.
- CRAAP Test Infographic — One-page visual reference for evaluating sources.
Slide Concepts
| Slide | Content |
|---|---|
| 1 | Title: "Email & the Web" |
| 2 | Email Anatomy — labeled example |
| 3 | Professional vs Unprofessional Email — side-by-side |
| 4 | Email Etiquette Rules — top 5 |
| 5 | Web vs Internet — they're not the same |
| 6 | URL Anatomy — breaking down an address |
| 7 | Search Engine Tips — quotation marks, minus sign, site: operator |
| 8 | CRAAP Test — evaluating sources |
| 9 | Activity: Evaluate 3 sources |
Vocabulary
| Term | Definition |
|---|---|
| Network | Two or more connected devices that can share resources and communicate |
| LAN (Local Area Network) | A network covering a small area like a home, office, or building |
| WAN (Wide Area Network) | A network spanning a large geographic area, connecting multiple LANs |
| Internet | The global network connecting millions of networks worldwide |
| ISP (Internet Service Provider) | A company that provides Internet access (Comcast, AT&T, etc.) |
| Modem | Device that connects a home network to the ISP |
| Router | Device that directs network traffic and connects devices to the Internet |
| Switch | Device that connects multiple devices on a LAN |
| IP Address | A unique numerical address assigned to every device on a network |
| DNS (Domain Name System) | Service that translates domain names (google.com) into IP addresses |
| HTTP / HTTPS | Protocols for transferring web pages; HTTPS adds encryption |
| Packet | A small unit of data transmitted over a network |
| TCP/IP | The foundational protocol suite for Internet communication |
| Wi-Fi | Wireless networking technology based on radio waves |
| Ethernet | Wired networking technology using cables (RJ-45 connectors) |
| Bandwidth | The maximum data transfer rate of a network connection |
| Electronic mail; messages sent between users via the Internet | |
| SMTP | Protocol for sending email |
| CC / BCC | Carbon Copy (visible to all) / Blind Carbon Copy (hidden from others) |
| URL (Uniform Resource Locator) | The address of a resource on the web |
| Web Browser | Software for accessing and viewing web pages |
| Search Engine | A tool for finding information on the web (Google, Bing) |
| CRAAP Test | Framework for evaluating information: Currency, Relevance, Authority, Accuracy, Purpose |
| Cloud Computing | Delivering computing services over the Internet (storage, apps, processing) |
| Spam | Unsolicited bulk email, often commercial or malicious |
Activities & Assignments
In-Class
- Network Diagram Drawing: Students draw their home network from memory, then compare with a partner. Identify modem, router, and connected devices.
- Professional Email Workshop: Write a professional email for a given scenario (emailing a professor about a missed class, applying for a job, requesting information). Peer review.
- Source Evaluation: Three sources on "Are video games harmful?" — evaluate each with the CRAAP test. Class discussion on which is most credible and why.
Homework
- "How Does Netflix Get to My TV?" (1 page): Trace the journey of a video from Netflix's servers to your screen. Mention: Internet, ISP, modem, router, Wi-Fi/Ethernet, streaming protocol. Use the terms from class.
- Email Etiquette Scenarios: Given 5 email situations, write appropriate subject lines and opening sentences. Identify when to use CC vs BCC.
- Search Engine Challenge: Answer 5 research questions using advanced search techniques (quotes, site:, minus sign, date filters). Document the search strategy used for each.
Discussion Questions
- If DNS stopped working tomorrow, what would happen? Could you still use the Internet?
- Why does HTTPS matter? What could happen on an unencrypted connection?
- Is email "private"? Who might be able to read your emails? (ISP, employer, government, hackers)
- Your grandparent shares a health article on Facebook. How would you evaluate whether to trust it?