1 - Start ~4 mins
Last time you followed a message from your browser out to a server and back. Today the question is different: when you type words into a search box, how does the computer decide which pages to show you, and in what order?
You will act as the search engine yourself, then try real searches and notice what changes the order of the results.
Quick recap hook: ask one student what a browser does when you type a full web address (it fetches that exact page). Then ask what happens when you type a few words instead. The gap between those two answers is today's lesson.
Keep this under four minutes. Devices stay closed until the exploration step.
2 - Browser or Search Engine? ~6 mins
A web browser is the app you open pages in (Chrome, Edge, Firefox, Safari). You give it an address, and it fetches that page.
A search engine is a service that finds pages matching the words you type, then puts them in an order it thinks will help you. Google, Bing and DuckDuckGo are search engines. You usually reach them through a browser.
Behind the scenes a search engine roughly does three jobs:
- Crawl: visit pages across the web and follow the links on them.
- Index: store what each page is about so it can be looked up quickly.
- Rank: when you search, put the matching pages in an order based on word match and other signals. You will try these next.
Ranking is the part people argue about, because different goals produce different orders. You are about to try that for yourself.
Name the mix-up up front: many students say "I Googled it on Chrome" and treat browser and search engine as the same thing. Hold up or point to the browser window and the search box inside it as two different tools.
Walk the three jobs (crawl, index, rank) against the diagram. Keep rank at "word match and other signals"; do not list recency, links or keyword stuffing here. Those land in the feed-ranker takeaways once students have felt them.
Misconception to head off: "the first result is always the best page." Ranking is a guess at usefulness for a goal, not a truth ranking.
3 - Hands-on: Be the Search Engine ~12 mins
Someone has searched for how do I start coding. Four pages could answer them. Put the pages in the order you would show them, then compare your order with how a real ranker orders them under two different goals.
For each goal, read the takeaway: it tells you what that ranking was optimising for.
Be the search engine
Run this on the board or on student devices. Give two minutes for a first personal ranking before anyone reveals a goal order, so students have a stake in the comparison.
After the "most useful" goal, ask who put the shop page first and why. After the "count the words" goal, name keyword stuffing in plain language: repeating the search words on purpose to climb the list.
Look-fors:
- Students noticing that "matches the words" alone is not enough
- Someone defending the old blog post because it is detailed, even if dated
- A student connecting ranking goals to "who decides what I see"
If time is tight, run only the two goals and skip a full class debrief; the takeaways carry the teaching point.
4 - Hands-on: Same Search, Different Results ~12 mins
Run 3 short trials; write one line each for the first two. Your teacher leads Trial 1. Then pairs try Trial 2. Trial 3 is extra if you finish early.
Trial 1: search vs address (whole class). Watch your teacher type a full site address (for example www.met.ie) into the address bar and open that page. Then watch them type only the words Irish weather forecast into a search engine. What is different about how the page was reached each time?
When Trial 1 is done, move on:
- Trial 2: change the words (pairs, about 3 minutes). Search for GAA fixtures this weekend, then search for hurling matches Saturday. Do the top results change? Which words seem to pull different pages up?
- Trial 3 (extra): change one detail (pairs). Pick one of those searches and try it again with a small change: add a year, a county name, or the word live. What moves up or down?
Write in your copy / on the exit slip:
- Trial 1: what was typed / how getting there differed
- Trial 2: wording change / what reordered
If you do Trial 3, add one more line: detail added / signal that seemed to matter (words, freshness, location, popularity).
Done looks like:
- You can say in one sentence how typing an address differs from searching with words
- You have one concrete example of a wording change that reordered the results
Devices open now. Prefer a search engine the school does not block; any major one is fine. If filtering is heavy, pick safer queries yourself (school subjects, public data) and put them on the board.
Pacing: Trial 1 whole-class on the board (about 3 minutes) as a fast win on address versus words. Put a visible timer up for Trial 2 (about 3 minutes) and take one shouted observation before anyone starts Trial 3. Trial 3 is optional extension only; do not hold the class for it. Bring everyone back with about two minutes spare so two volunteers can read one capture line each before Make sense.
The done bar is two capture lines (Trial 1 and Trial 2). Circulate and push for specific observations ("the RTÉ page jumped above the forum when I added the year") rather than "it changed".
Common snag: students type a search into the address bar and the browser quietly forwards it to a search engine. If that happens, name it: the browser still did not rank pages itself; it handed the words to a search engine.
5 - Make Sense ~3 mins
A browser fetches the page you name. A search engine finds candidate pages and ranks them for a goal.
Ranking is not a single score of "best page". It weighs signals such as word match, how recent a page is, and who links to it. Change the goal, or change the words, and the order changes with them.
Three cold-call prompts if the room is quiet: (1) browser vs search engine in one sentence each, (2) one signal the ranker used that you had not weighed, (3) why stuffing a page with the search words is a weak long-term strategy.
If anyone still calls the top result "the best page", ask "Best for whose goal?" and point back to the two feed-ranker takeaways by name so the interactive and the live searches feel like one idea.
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