Year 8 Science · Unit 4 · Lesson 16
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Learning Goals
Break down the model
A bushfire spread model is used by the NSW Rural Fire Service. For each part of the model below, write whether it is an INPUT, the CALCULATION or an OUTPUT, then explain your choice in a few words.
| Part of the model | Input / Calculation / Output | Why? |
|---|---|---|
| The current wind speed, temperature and humidity. | ||
| The computer works out how far the fire front moves every few minutes. | ||
| A map showing the predicted fire path over the next three hours. | ||
| The type of bush and how dry the fuel is. |
Judge the forecast
Scenario
The Bureau of Meteorology publishes two forecasts for the same town on the same day:
Forecast A: tomorrow, 80% chance of rain.
Forecast B: in 12 days, 80% chance of rain.
(a) Which forecast should you trust more, and why?
(b) Explain, using the idea of step-by-step calculation, why errors build up the further ahead a model predicts.
(c) Describe one thing the Bureau could do to make its model more accurate over time.
1. A council wants to know which streets will flood in a big storm. Explain why a computer model is a better choice than waiting for a real flood.
2. A student says 'The model is on a computer, so its answer must be correct.' Identify two problems with this thinking.
Wrap Up
In one sentence, what is the difference between an input and an output in a computer model?