Geography K–10 · Years 3–4
Where is Earth's water: dividing one litre by the real proportions
Geography (HASS F–6 sub-strand) with Science understanding, Earth and space sciences (ACARA Year 4); NSW Geography K–10 (2015) Stage 2 focus area: The Earth's Environment (Significance of environments)
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The idea
Almost all of Earth's water is sea water and most fresh water is ice or underground, so the water people draw from rivers and lakes is a tiny share.
What you need
- 1 L measuring jug of water
- 1 × 25 mL measuring cylinder, 1 × 10 mL syringe, 1 dropper (about 0.05 mL per drop)
- Six labelled clear vessels, each sized for what it receives: a 1 L clear jar or beaker for oceans (it takes 965 mL, most of the jug), a 25 mL cup for ice (17.4 mL), a 10 mL cup for fresh groundwater (7.6 mL), and three 10 mL cups for fresh lakes, atmosphere and rivers, which receive one drop, part of a drop and nothing the class can measure
- Table of USGS volumes in km³ (USGS Water Science School): oceans, seas and bays 1 338 000 000; ice caps, glaciers and permanent snow 24 064 000; fresh groundwater 10 530 000; fresh lakes 91 000; atmosphere 12 900; rivers 2 120; total of all rows on the table 1 385 984 510
How to do it
- Calculate each store as a share of the total and as mL of the 1 L jug (the calculator below does the division).
- Measure 17.4 mL into the ice cup with the cylinder, 7.6 mL into groundwater with the syringe, and about one drop into lakes (0.066 mL; one drop from the dropper is about 0.05 mL).
- Try to measure the atmosphere (0.009 mL) and rivers (0.0015 mL): a single drop is too much for either. Record that fact.
- Pour the remaining water (about 975 mL) into the oceans cup: 965.4 mL of it stands for the oceans and the other 9.6 mL for the stores not given their own cup: saline groundwater (9.3 mL), ground ice and permafrost, saline lakes, soil moisture, swamp water, biological water, the atmosphere and rivers.
- Line the cups up and photograph them with labels; write one sentence for each cup about where people could draw water from it.
What you should see
Oceans 965.4 mL, ice 17.4 mL, fresh groundwater 7.6 mL, fresh lakes 0.066 mL, atmosphere 0.0093 mL, rivers 0.0015 mL, computed 22 September 2026 from the USGS volumes divided by the sum of every row on the USGS table. The learner sees that rivers and lakes together are less than two drops in a litre and that fresh groundwater is the largest liquid fresh store. It worked if the cups hold the measured volumes and the atmosphere and river cups stay empty with a note explaining why.
What changes
This activity lists no variables to change, measure and keep the same.
Common misconceptions
Each of these ideas is wrong, and the activity is a chance to test it.
- Most of Earth's fresh water is in rivers and lakes.
- Ice does not count as water.
Safety card
Hazards
No hazard is listed.
Controls
No control is listed.
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.
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.GE2-2
- Human Society and its Environment K–6 Syllabus (2024), NESA; implementation from 2027, not yet taught; code read on this page on 22 September 2026HS2-GEO-01
- Australian Curriculum v9AC9HS4K05AC9HS4K06AC9HS4S03AC9S4U02
Sources
The pages the author read to write this activity.