Geography K–10 · Years 1–2
Make a rain gauge and keep a monthly rainfall record
Geography (HASS F–6 sub-strand) with Science understanding, Earth and space sciences, and Science inquiry, Planning and conducting (ACARA Year 1); NSW Geography K–10 (2015) Stage 1 focus area: Features of Places (Weather and seasons)
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The idea
Rainfall is a depth of water spread over the ground, so a straight-sided container measures it in millimetres regardless of the container width.
Safety card
Hazards
- cut edge of a trimmed PET bottle
- stake in the ground
Controls
- adult trims the bottle and tapes the edge
- stake flagged and placed away from play areas
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 clear straight-sided jar or cut 2 L PET bottle (the sides must be vertical for a direct mm reading)
- 1 plastic funnel whose rim diameter equals the container diameter (or a bottle top inverted into its own base)
- 30 cm ruler or a paper mm scale taped to the outside, with its zero set level with the ballast water surface described below and not at the inside base, so that what is read is rain and not the ballast water underneath it
- A few pebbles as ballast, covered with water; the water surface just over the pebbles is the zero line
- Open site: a wooden stake so the rim sits level, about 30 cm above the ground, away from walls, roofs and trees
- A measuring jug or cylinder marked in mL, needed only if the funnel is wider than the container
- Class rainfall table for 20 school days
How to do it
- Fit the funnel in the container so the rim is level. Add the pebbles, pour in water until it just covers them, and mark that water surface as the zero line.
- Place the gauge in the open on the stake, rim about 30 cm above ground and as far from walls, roofs and trees as the site allows.
- Each morning at the same time, read the water level against the scale to the nearest mm; then tip the water out to the zero line, or top it up to the zero line if evaporation has taken it below.
- Write the depth in the table. Write 0 on dry days; leave a mark for weekends and add the Monday total as "since Friday".
- After 20 school days add the column to get the month total and find the wettest day.
- Compare the month total with the nearest Bureau of Meteorology station for the same dates (Climate Data Online, daily rainfall) and talk about why the two differ. The Bureau dates a daily total to its 9 am observation, so the figure printed against a date is the total from 9 am the day before to 9 am on that date; line the two records up on that basis before any single day is compared.
What you should see
A month of daily depths in mm. If the container is straight-sided, the reading is the rainfall depth directly. If a wide funnel feeds a narrow container, the calculator below converts the collected volume to depth: a 100 mm funnel collects 7.85 mL for each 1 mm of rain, so 78.5 mL means 10.0 mm. The class total can differ from the Bureau station's because rain varies over short distances, most of all in storms; a large gap on a single day is checked first against the Bureau's 9 am to 9 am dating, which puts a reading taken at a school morning time one day out from the Bureau's column, and then against a blocked funnel, a tipped gauge or splash-in.
What changes
- What you change
- day (date of reading)
- What you measure
- rainfall depth in mm
- What you keep the same
- reading time
- gauge position
- emptying to the zero line after each reading
Common misconceptions
Each of these ideas is wrong, and the activity is a chance to test it.
- A wider bucket collects more rain, so it shows a bigger rainfall.
- Rainfall is measured in litres.
- A gauge under a tree gives the same reading as one in the open.
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.GE1-1GE1-3
- Australian Curriculum v9AC9HS1S02AC9HS2S03AC9S1U02AC9S1I03
Sources
The pages the author read to write this activity.