Science and Technology K–6 · Kindergarten
Making and reading a rain gauge
Earth and Space (NSW 2017); Science inquiry and Science as a human endeavour (ACARA v9)
The idea
Rain collects to the same depth in every straight-sided container, whatever the width of its opening, and that depth in millimetres is what a rainfall figure means.
What you need
- A straight-sided clear plastic container whose opening is as wide as its base (no shoulder or narrow neck), with a clear plastic ruler marked in millimetres taped upright to the outside for the adult to read, its zero level with the inside of the base
- A second, wider container that is also straight-sided with an opening as wide as its base, with a ruler taped on the same way (check the sides: a tub that is wider at the top than at the base reads too high)
- A brick for each container, taped to the outside of the container to stop it blowing over (nothing is put inside, because anything standing in the water raises the reading); an open spot away from roof edges and trees
- A strip of masking tape stuck up the side of each container and a marker, so learners mark and date each morning's water level
- A weekly recording table with a column for each container
How to do it
- Set both containers in the open spot at the same time on a day rain is forecast, each taped to its brick on the outside.
- At the same time the next morning mark the water level on each container's tape and write the date beside the mark, eyes level with the water. Stand the two containers side by side and compare the two marks. The adult reads each depth against the ruler to the nearest millimetre for the class chart, and writes less than 1 mm for any water below the first mark.
- Empty both and set them again. Keep going for the week.
- Compare the two marks each day, and the two depths the adult read. Are they the same.
- Compare the week's total with the Bureau of Meteorology figure for the nearest station shown by the teacher.
What you should see
On a rainy day the two tape marks sit at the same height when the containers are stood side by side, and the adult's two readings agree to within the smallest mark (1 mm), because rain depth does not depend on the width of the opening when the sides are straight. One millimetre of rain is one litre over every square metre (0.001 m times 1 m^2 equals 1 L). The Bureau of Meteorology's standard instrument is the 203 mm (8 inch) rain gauge; the class gauges fill to the same depth with other openings. The adult reads to the nearest millimetre rather than the nearest 5 mm, so light falls of 1 or 2 mm are recorded instead of reading zero and the week's total is not thrown out by rounding. The learner knows it worked when the two marks line up and a dry day leaves no mark above the base.
What changes
- What you change
- width of the container
- What you measure
- the height of each morning's level mark, compared between the two containers; rain depth in millimetres, read by the adult
- What you keep the same
- straight sides
- same spot
- same reading time
- emptied together
- nothing inside the containers
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 number.
- A little rain is 1 cm (it is measured in millimetres).
Safety card
Hazards
- Slippery ground when wet
Controls
- Plastic containers only; an adult carries the containers on wet ground
Note
No chemicals or heat. Record the activity on the school's risk assessment (Primary School RiskAssess, Ecosolve Australia, riskassess.com.au).
Curriculum references
The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.
- Science and Technology K-6 Syllabus (2017), NESA. Current syllabus; NESA's timeline is 2026 plan and prepare, 2027 start teaching the 2024 syllabus. Code read from the official syllabus document on 2026-09-22.STe-6ES-SSTe-1WS-S
- Science and Technology K-6 Syllabus (2024), NESA. Implementation from 2027, so this code describes the future syllabus. Code read from the outcomes page on 2026-09-22. The 2024 Early Stage 1 content has no weather: 'Observe and record daily weather to identify changes and patterns' is Stage 1 content (ST1-SCI-01), so from 2027 this activity's weather science sits at Stage 1 and only this inquiry outcome applies at Early Stage 1.STE-PQU-01
- Australian Curriculum v9AC9SFH01AC9SFI02AC9SFI03AC9SFI05
Sources
The pages the author read to write this activity.