Grade 12 · Week 05 · Thursday · Day 04

Motion Model Detective Lab

Learning objective: Test two preloaded synthetic datasets, examine residual graphs and make defensible model selections.

45–60 minutes · Offline-capable · Public practice, not a supervised examination

Read and reason

Control which dataset you study

The studio includes two synthetic motion examples. One follows an approximately uniform-velocity trend and one an approximately constant-acceleration trend, both with small invented deviations. The tool plots position against time, fits linear and quadratic curves using five training points, and checks the prediction at a sixth held-out point. You may inspect both datasets to see that the curve with more coefficients is not automatically the best scientific choice.

Read a residual plot

Plot residual r versus time. A residual close to zero indicates that prediction was close at that moment; a pattern of alternating positive and negative values may indicate overfitting or limitations, depending on context. The residual graph's vertical axis is measured in meters. You should discuss whether its scale is reasonable compared with measurement resolution and the time interval rather than looking only at how smooth the model curve appears.

Make a defensible selection

Report your chosen model, training RMSE, absolute holdout error, number of fitted parameters, and plausible physics. For the intentionally near-linear dataset, favor parsimony unless evidence supports acceleration. For the curved dataset, a quadratic mechanism may be reasonable if its prediction and residual pattern improve meaningfully. A six-point invented dataset cannot prove a general physical law.

Safety, transparency and reusability

The model uses data generated from formulas, not actual video or motion-sensor readings. Its mathematical process is reproducible and standalone. Never collect identifiable video of others without permission; recording real motion requires consent and suitable supervision. The dataset CSV is available offline so a student can independently calculate sample residuals without running the interactive graph.

Vocabulary in context

investigation
A structured test involving a question, models, data and evidence.
assumption
A condition treated as true for a model or method.
extrapolation
Predicting beyond the observed time interval.
validation
Checking a model's predictions against observations not used to fit it.
limitation
A restriction on the inference that can be supported.

Use every term in a short original sentence or model explanation.

Worked example

Data generated near x=1+2t have almost constant first differences in time. Data generated near x=1+2t+0.5t² have increasing first differences. This provides a physical clue, but the model comparison must still include the numerical fit and limitations.

Show substitutions, signs and SI units in your own notebook.

Independent science notebook

Run both datasets, choose a plausible model for each, record at least three signed residuals, and export the evidence notebook. Explain one scenario where a new datapoint could change your conclusion.

Your work stays in the local browser when possible. Export your notebook for backup.

Daily retrieval practice · four questions

Open-book practice with feedback and an 80% correction target. Randomized answers do not constitute a confidential official exam.

Continue

Select an artifact for your evidence portfolio. Explain what it supports and one factor it cannot establish.