Grade 12 · Term 1 · Unit 1 · Simulations · Chapter 3

Running & Interpreting Simulations

Week 3 · Benchmark 12.5.1.1 Run and interpret simulations

Essential question

How do we know a simulation's result is trustworthy?

Learning objectives

Run a simple simulation using PhET, Scratch or Tinkercad
Identify inputs, parameters and outputs
Validate a result and describe the limitations of the model

Overview

Every simulation has three parts: what you feed in (inputs and parameters), what happens inside (the model), and what comes out (outputs). Running a good simulation is only half the job — you also have to check whether the answer is believable and explain what the model does NOT capture. This week you will run a PhET or Tinkercad simulation and write a short report.

A projectile motion simulation showing a parabolic trajectory with sliders for angle, velocity and gravity. — A projectile-motion simulation: sliders on the left set the inputs (angle, launch velocity) and parameter (gravity); the output is the parabolic path and the range read on the right.
Marianville ICT — generated illustration · CC BY 4.0

Inputs, parameters, outputs

Inputs are the values that change each run (e.g. angle of launch). Parameters are settings you keep fixed for a scenario (e.g. gravity). Outputs are the results you measure (e.g. distance travelled).

Validation and sensitivity

Validation means comparing simulation output to a known real answer or another trusted source. Sensitivity analysis means changing one input at a time to see how much the output changes — an output that swings wildly for a tiny change is 'sensitive' and risky to trust.

Limitations of models

Every model leaves something out. A projectile simulator often ignores air resistance; a traffic simulator may assume all drivers obey the rules. Good ICT students state these limits clearly in their reports.

Activity

Projectile motion lab

Open PhET 'Projectile Motion' (or an offline copy) on the lab PC.
Fire the cannon at 30°, 45° and 60° with the same speed. Record range each time.
Answer: which angle gives the greatest range, and why? What does the model ignore?

Review questions

What is the difference between an input and a parameter?
Reveal answer
An input changes each run; a parameter is a fixed setting for the scenario.
Define sensitivity analysis.
Reveal answer
Changing one input to see how much the output changes.
Name one limitation of a school projectile simulator.
Reveal answer
It usually ignores air resistance.

Take it home

Repeat the lab with air resistance ON. How does the 'best' angle change?

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