IA idea · Differential equations & dynamics

How fast does news spread through a year group?

AI SLAI HLAA SLAA HL Solid Also in: Statistics, Networks & graphs

Research question

Does the number of students who have heard a (harmless, invented) piece of news over a day follow a logistic model, and does a model with “stiflers” who stop spreading fit better?

Adapt it: change the place, the data or the comparison until the question is yours.

Why it makes a good exploration

Rumours spread like diseases but people stop repeating stale news. An ethical, harmless experiment in your year group gives unusual primary data for a modelling question.

The mathematics you'll need

Logistic growth and fitting
A simple rumour model (Daley–Kendall style) with Euler's method (HL)
Comparing models with residuals
Survey design and sampling

Course labels show where a technique sits; using maths from outside your course is fine if you explain it clearly and say it is new to you.

Where the data comes from

With teacher approval, seed harmless news (e.g., a fun fact) with a few students and survey who has heard it at set times.

Desmos graphing calculator — Free graphing and regression (y₁ ~ ax₁ + b) — fit models to your data and show residuals.

Cite every source in a footnote where you use it and in your bibliography. Check the licence of any dataset you download.

A possible outline

Design the experiment ethically with your teacher.
Collect timed survey data.
Fit a logistic model.
Build a rumour model with spreaders and stiflers.
Compare and reflect on social groups and online spreading.

Pitfalls that cost marks

Anything that could embarrass or mislead people — keep it harmless and approved.
Self-reported timing errors.
Too few time points.

Showing personal engagement

Run the experiment yourself and describe surprises.
Compare spreading within friendship groups and across them.
Relate to misinformation online.

See Criterion C: personal engagement for what examiners look for.

Taking it further

HL: explain why the classic rumour model predicts that about 20% of people never hear the rumour, and test that against your data.

Turn this idea into your IA

Plan this IAOpens the planner with this question, the maths and data sources filled in. Desmos workspacePlot your data, fit models and keep your graphs with your plan. AI feedback on a draftCriterion-by-criterion feedback with evidence from your own text. Coaching, not rewriting. Examiner reviewPete, a practising IA examiner, reads your draft and talks it through with you (€100).