The shape of the lesson
By the end of the lesson, learners can
- HTTP: request and response: In the lab, watch the request leave the browser and the response come back from the web server.
- HTTPS: the secure version: HTTPS works in the same request and response way, but it adds security on top.
- What a browser does: A web browser is application software.
- HTTP: protocol for requesting and transferring web pages between browser and web server.
- HTTPS: HTTP with encryption by SSL/TLS; intercepted data cannot be understood.
- Browser purpose: render HTML and display web pages.
- Browser functions: bookmarks, history, tabs, cookies, navigation tools, address bar.
One picture every idea returns to
Hypertext transfer protocol (HTTP) is the set of rules for transferring web pages between a web browser (the client) and a web server: the browser sends a request, the server sends a response containing the files. HTTPS is HTTP made secure: the data is encrypted using the SSL/TLS protocol, so if it is intercepted it cannot be understood. The main purpose of a web browser is to render HTML and display web pages.
Forty-five minutes, phase by phase
| Time | Phase | What happens in the room | Grouping |
|---|---|---|---|
| 0 to 5 min | Hook: predict | Open with the question in the title, Ask, then render.. Every time you open a page, your browser and a web server hold a short conversation following agreed rules: HTTP. Put the figure on the board: it is the one picture every idea in the lesson returns to. | Whole class, then pairs |
| 5 to 13 min | Teach and check: HTTP: request and response | In the lab, watch the request leave the browser and the response come back from the web server. Project tab 1 of the lab (HTTP and HTTPS) and let a student drive it while the class predicts. | Whole class, then pairs |
| 13 to 21 min | Teach and check: HTTPS: the secure version | HTTPS works in the same request and response way, but it adds security on top. | Pairs |
| 21 to 30 min | Teach and check: What a browser does | A web browser is application software. | Jigsaw |
| 30 to 36 min | Check | The four Stage 1 questions from the student lesson, answered on mini whiteboards or by show of fingers. Re-teach the one most get wrong. | Individual, then whole class |
| 36 to 43 min | Plenary | The exam-style questions from Stage 2, one at a time: thirty seconds alone, then a random call. The feedback lines in the key give the examiner's wording. | Individual, random call |
| 43 to 45 min | Exit and homework | Set the worksheet below (6 questions, 14 marks). Learners self-assess against the objectives before they leave. | Individual |
Protect the parts that carry the learning
The sequence carries about fifty minutes of material, so the lab is driven by one student while the class predicts rather than explored freely. Times are a guide.
Protected: the check at 30 minutes. It is the only individual read on whether the key idea landed, and it is not cut.
Cut first if the build overruns: the last check in What a browser does, never the check or the plenary.
In a 60 minute block: run worksheet questions 1 to 3 in class as a Rally Coach set and model both the hardest worked example and its check live.
Jigsaw
Split the content into expert pieces. Expert groups master one piece each, then regroup so every home team has one expert per piece, and each expert teaches their piece to the team.
The full structure, with its variations and the other twelve, is on the cooperative-learning page.
What to head off, and how
| Trap learners fall into | Teaching move that pre-empts it |
|---|---|
| HTTPS does not stop data being intercepted. | It means that intercepted data is encrypted, so it is meaningless without the key. Write "cannot be understood", not "cannot be stolen". |
| A web browser is not a search engine. | The browser displays pages; a search engine is a website that you visit using a browser. |
HTTP, HTTPS and web browsers: worksheet
6 questions, 14 marks. Written in the style of the papers; no past paper question is reproduced.
Describe the purpose and operation of hypertext transfer protocol (HTTP).
Explain why an online shop uses HTTPS rather than HTTP on its checkout page.
State the main purpose of a web browser.
Identify four functions of a web browser, other than displaying web pages.
A user types a URL into a browser. Describe how the user can tell whether the page uses HTTPS.
A student writes: "HTTPS means that hackers cannot intercept your data." Explain why this is not correct.
Answer key and marking notes
- HTTP is a protocol / set of rules for transferring web pages / data on the world wide web.
- The web browser sends a request to the web server for a web page.
- The web server responds by sending the web page files (HTML) back to the browser.
- HTTPS encrypts the data (using SSL/TLS) sent between the browser and the server.
- So if payment / personal details are intercepted they cannot be understood (and the certificate shows the site is genuine).
To render HTML and display web pages.
- Storing bookmarks / favourites.
- Recording user history.
- Allowing multiple tabs.
- Any one of: storing cookies, providing navigation tools (back / forward / refresh), providing an address bar.
- The URL in the address bar begins with https://.
- The browser displays a padlock symbol (which can be clicked to view the site's digital certificate).
- Data sent using HTTPS can still be intercepted.
- But it is encrypted, so the hacker cannot understand / read it without the key.
6 multiple-choice questions on this lesson
From the topic question bank. Assign them in the app for a marked score in your gradebook, or run the topic as a class game.
What is the purpose of hypertext transfer protocol (HTTP)?
- AIt is the set of rules for requesting and transferring web pages between a browser and a web server
- BIt translates domain names into the IP addresses of web servers
- CIt is the language that the content of web pages is written in
- DIt stores the URLs of pages so the user can revisit them
How does HTTPS differ from HTTP?
- AHTTPS encrypts the data sent between browser and server using SSL/TLS
- BHTTPS sends web pages faster by compressing them
- CHTTPS stops data being intercepted while it is transmitted
- DHTTPS removes the need for the web server to send a response
A student has a timetable, an email and a revision website all open in one browser window and switches between them. Which browser function is this?
- AAllowing multiple tabs
- BRecording user history
- CStoring bookmarks
- DProviding navigation tools
Which web page most needs to use HTTPS?
- AA page where a customer enters their card number to pay
- BA page listing a museum's opening times
- CA page showing the rules of a board game
- DA page displaying a map of a school site
A hacker intercepts the data sent from a user's browser to a website that uses HTTPS. What does the hacker obtain?
- AEncrypted data that cannot be understood without the key
- BNothing, because HTTPS data cannot be intercepted
- CThe data in plain text, because HTTPS only protects the server
- DOnly the images on the page, because text is always encrypted
Which statement about a web browser is correct?
- AIt is application software whose main purpose is to render HTML and display web pages
- BIt is a search engine that stores copies of every website
- CIt is system software that gives each device its IP address
- DIt is the protocol that transfers pages from the web server
Quiz key
HTTP is the protocol that lets a browser request a page and the web server respond with its files. Translating domain names is done by the DNS, pages are written in HTML, and storing URLs to revisit is the bookmarks function of a browser.
HTTPS adds encryption using the SSL (or TLS) protocol, and the server proves its identity with a digital certificate. It does not compress pages or make them faster. Data can still be intercepted, but it cannot be understood. The request and response still happen exactly as with HTTP.
Multiple tabs let several pages be open at once in one window. History is a list of pages already visited, bookmarks save URLs for later, and navigation tools are the back, forward, refresh and home buttons.
Card numbers must be encrypted so that, if intercepted, they cannot be understood, so the payment page needs HTTPS. Opening times, game rules and a school map are public information with no personal data being sent, so encryption matters far less (although many sites now use HTTPS everywhere).
HTTPS encrypts all the data with SSL/TLS, so the hacker can capture it but sees only meaningless ciphertext without the key. Saying it cannot be intercepted is the common misconception. With HTTPS the data is not sent as plain text, and the whole transfer is encrypted, not just the text.
A web browser is application software: its main purpose is to render HTML and display the page, along with functions such as bookmarks, history, tabs and cookies. A search engine is a website you visit using a browser. IP addresses are not assigned by the browser, and the protocol for transferring pages is HTTP or HTTPS.
What to project
The student lesson embeds these tabs. Open them full screen on the projector; every slider has a drag handle on the stage.
Slides for this lesson
A projectable deck for every pack is on the way. Until then, present the student lesson full screen: its sections, figure and lab tabs follow the same order as the plan above.