A CS Unplugged activity where students simulate a social media feed algorithm using cards — exploring engagement loops, filter bubbles, and data ethics without a screen in sight.
The UK government has announced a ban on social media for under-16s. But before discussing whether that is right or wrong — do your students actually know how social media decides what appears on their screen?
It is not random. It is not chronological. It is an algorithm — and understanding how it works is one of the most important things a young person can learn about the digital world.
This activity lets students simulate a social media feed algorithm using cards and coloured dots. No accounts, no screens, no phones — just a surprisingly illuminating set of decisions.
20 index cards, each representing a piece of content — write a brief description on each: a funny video, a news story, an advert, a post from a friend, a political opinion, a celebrity photo
Sticky labels or coloured dots to represent user preferences
Groups of 4–6 students (works equally well as a whole-class activity)
Approximately 30–45 minutes
Shuffle the cards and deal them out in order. Everyone sees the same content in the same sequence. This is how social media used to work in the early days.
Discuss
Assign each student a profile: one loves sport, one loves music, one is interested in politics, one just wants to see friends' posts. Give each card a score from 1–3 for how relevant it is to each profile. Each student sorts their cards by score, highest first. This is their personalised feed.
Discuss
Remove the scoring system. Students now choose which cards they would stop and look at — whichever grab their attention. Mark those cards. Reshuffle and deal again, but this time cards that were previously marked are dealt first.
Discuss
Students just simulated the core mechanism behind every major social media platform.
The algorithm does not show users what is true, or what is good for them. It shows what keeps them looking — because every second spent on the platform is a second it can show an advert.
Engagement-based algorithm
The more a user interacts with a type of content, the more of it they see.
Filter bubble
The feed narrows over time until it mostly confirms what you already think.
Feedback loop
Behaviour shapes the algorithm; the algorithm shapes behaviour.
Who is responsible for what the algorithm promotes — the platform, the users, or both?
Could you design a fairer algorithm? What would you optimise for instead of engagement?
Should algorithms be transparent — should users be able to see why they are being shown something?
The UK government has announced a ban on social media for under-16s. Is understanding how algorithms work a better solution, a worse one, or something that should happen alongside the ban?
These work well as a written reflection, class debate, paired discussion, or homework task.
| Topic | Connection |
|---|---|
| Algorithms | How rules and conditions produce outputs from inputs |
| Data and its uses | How platforms collect and act on behavioural data |
| Ethical and legal issues | Who is responsible for algorithmic outputs |
| Artificial intelligence | How machine learning refines recommendations over time |
| Social effects of computing | Filter bubbles, misinformation, and platform design |
GCSE
Write pseudocode for a simple recommendation algorithm that takes user history as input and outputs a ranked feed.
A Level
Research and compare the Facebook News Feed, YouTube recommendations, and TikTok's For You page. What are the ethical implications of each?
All students
Spend one day noting every time an algorithm makes a decision for you — Netflix, Spotify, Google, maps. Discuss findings as a class.
Want more activities like this?
New CS Unplugged activities are added regularly — all written by a Senior Examiner and Head of CS, with full curriculum links.