dcf.cymru stimulus sheet · PSE / Well-being · Year 9
Everything on this sheet is invented. The school, the pupils and the numbers about the school are made up for this lesson. The only real figure is the population of Wales, in the box at the bottom.
Ysgol Glan Tywi is a secondary school with 1,000 pupils. On Friday at 19:00, a Year 9 pupil posts a message in a small group chat with 3 friends. The message says that Tomos, another Year 9 pupil, cheated in Thursday’s maths test by copying answers.
It is not true. Tomos did the test on his own. Nobody checked before they passed the message on.
The 3 friends each send it on to other people, and those people send it on again. By the time Tomos picks up his phone, people he has never spoken to are talking about him.
At 19:45, Nia, who sat next to Tomos in the test, posts a correction: “That’s not true. I sat next to him. Please stop sending it.” She sends it to 4 people.
A model is a simplified version of something real, built from a few clear rules, so that you can work out what might happen. Scientists, banks, weather forecasters and health services use models every day. A good model is useful even though it is not perfect, as long as you know what it leaves out.
| Model | The rule after round 1 |
|---|---|
| Model A | Everyone who has just seen the rumour sends it to 3 new people. |
| Model B | Only 1 in 3 of the people who have just seen it send it on, each to 3 new people. The other 2 in 3 do nothing. |
| Model C | Half of the people who have just seen it send it on, each to 4 new people. |
| Model D | Only 1 in 4 of the people who have just seen it send it on, each to 2 new people. |
| Nia’s correction | Starts in round 3 with 4 people. After that, each round has 1.5 times as many new people as the round before. |
The models use averages. “Half of 3 people” is 1.5 people, which cannot happen to one group of friends, but across hundreds of group chats it gives the right average. Decimals in your answers are fine.