Geography K–10 · Years 5–6

Fire danger from the schoolyard: temperature, humidity and wind into the McArthur index

Geography (HASS F–6 sub-strand); NSW Geography K–10 (2015) Stage 3 focus area: Factors that Shape Places (Bushfire hazard)

Practical, model not builtLow risk

This site has no interactive model of its own. Where a step or a material names a Concept Studio model, simulation or tool, it has not been built; an external simulation a step names (for example PhET) is not part of this site.

The idea

Fire danger is set by weather that can be measured, and it rises steeply with heat and wind and falls with humidity, which is why the same bush can be safe one afternoon and dangerous the next.

Safety card

Low riskAn adult supervises

Hazards

sun exposure while reading instruments

Controls

hats; readings take under 10 minutes
no fire of any kind is lit: the investigation is measurement and calculation only

Note

No chemicals or heat are used. The activity is run under the school risk-assessment procedure; RiskAssess (riskassess.com.au) holds templates for school practicals and fieldwork. The NSW Department of Education Chemical Safety in Schools package is not triggered.

What you need

1 digital thermometer–hygrometer (temperature in °C and relative humidity in %) read in shade at about 1.2 m
1 hand-held cup or vane anemometer reading km/h
Record sheet for 5 school days, with readings at the same early-afternoon time each day inside school hours (for example 1:30 pm)
The Bureau of Meteorology observations for the nearest station, the reading nearest that time on the same days
The NSW Rural Fire Service fire danger rating for the school's area on the same days

How to do it

At the chosen time each day read the temperature and humidity in shade after the instrument has settled for 5 minutes.
In the most open spot of the school, hold the anemometer at arm's length above the head for 1 minute and record the mean wind speed. Write down the height it was held at (about 2.2 m at arm's length above the head) and what stands within 20 m of it: a reading taken among buildings is sheltered and reads lower than a wind measured clear of them on a mast, and the index answers to that difference as much as to the weather.
Copy the nearest Bureau station's temperature, humidity and wind for the observation nearest the chosen time on the same day.
Enter both sets of readings in the calculator with the drought factor set to 10 (fuel fully dry), then again at 5; record the four index values.
Record the RFS fire danger rating for the day and write down that it comes from the national system, not from this index.
Change one input at a time in the calculator (temperature up 5 °C, humidity down 10 %, wind up 10 km/h) and record how much the index changes.

What you should see

Five days of readings with units and four index values per day (school and Bureau readings, each at drought factor 10 and 5). The index is higher on hot, dry, windy afternoons and lower after rain. The school's wind reading, taken by hand at about 2.2 m among buildings, is sheltered and is expected to read lower than the Bureau station's, whose anemometer stands clear on a mast; the class compares the two indices and uses the wind factor below to say how much of the difference the wind measurement alone accounts for. From the model, 10 km/h more wind multiplies the index by e^0.234 = 1.26, and a 30 degree rise in temperature minus humidity multiplies it by e = 2.72. It worked if the class can say which single measurement changed the index most over the five days.

What changes

What you change: day, then each weather input in turn
What you measure: forest fire danger index
What you keep the same: same reading time each day
same instruments and position
drought factor held at a stated value

Common misconceptions

Each of these ideas is wrong, and the activity is a chance to test it.

Fire danger depends only on how hot the day is.
A cool, windy, dry day cannot be dangerous.
The fire danger rating is a forecast of where a fire will start.

Curriculum references

The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.

Geography K–10 Syllabus (2015), NESA; current and taught in 2026, replaced from 2027. The outcome codes are not printed on the NESA landing page for this syllabus, which only links the document, so the url given is the syllabus document itself (geography-k-10-syllabus-2015.docx); the code and its outcome text were read in that document on 23 September 2026.GE3-2 GE3-3 GE3-4
Human Society and its Environment K–6 Syllabus (2024), NESA; implementation from 2027, not yet taught; code read on this page on 22 September 2026. The syllabus outcomes page used in this file for HSE-GEO-01, HS1-GEO-01 and HS2-GEO-01 renders Early Stage 1, Stage 1 and Stage 2 outcomes only and carries no Stage 3 block (checked 23 September 2026), which is why the Stage 3 code is cited from its focus-area content page instead.HS3-GEO-01
Australian Curriculum v9AC9HS5K05AC9HS5S02AC9HS5S03

Sources

The pages the author read to write this activity.

All Concept Studio activities