Classroom lesson · ages 7–9
Where is Earth's water?
Most of it is in oceans, seas and bays: 96.5% of all the water the USGS table counts.
Real photograph · 228988681/Shutterstock.com · Shutterstock Standard (free image collection, API) License
Ready for the classroom
Paper, a pencil and a coloured pencil. The bar diagram and the table are on the projector and the worksheet.
Designed here for ages 7–9; adapt the vocabulary to your class. The age range and timings are teaching choices, not a claim of curriculum accreditation. See which curriculum statements this lesson can support.
Learning goal: read a real data table, find the biggest store of water, spot the frozen stores, and say that the table is one estimate.
Five-minute discussion
- First minute. Ask: if you could collect all of Earth's water, where would most of it come from? Everyone says or writes a first guess.
- Next two minutes. Show the bar diagram. Read the short answer together and point to the biggest store. Partners find the thin end of the bar.
- Final two minutes. Each pupil finishes the sentence: Most of Earth's water is in … . Keep the first guess to compare later.
Twenty-minute investigation
- Minutes 0–5. Use the short discussion above. Keep the first guesses: pupils will come back to them.
- Minutes 5–10. Pairs read the table on the worksheet. They colour the rows whose names mean frozen water, then find the biggest and the smallest store.
- Minutes 10–15. Compare two stores: all the world's rivers and the water in the atmosphere. Which number is bigger? Read the big numbers aloud by their commas.
- Minutes 15–20. Finish the worksheet. Talk about the table's edge: it is one estimate, and it stops at groundwater. Pupils revisit their first guess.
Words to know
- Cubic kilometre
- The unit the USGS table uses: a cube of water one kilometre long, one kilometre wide and one kilometre tall.
- Groundwater
- The water in the soil and rock you could reach by drilling a well.
- Saline
- Salty. More than half of the groundwater in the table is saline.
- Estimate
- The table calls itself “one estimate” of global water distribution, and that is the right word — nobody has measured the water in the world’s rock directly.
Projector view
Use the numbered links to move between prompts. They also work with Tab and Enter; no autoplay or animation.
One bar, the biggest store and the thin end
- 1. Oceans, seas and bays: the biggest store
- 2. Ice, groundwater and everything else: the thin end
The top bar is drawn in proportion from the table. The lower bar enlarges its thin end — ice, groundwater and everything else — so it is not to scale.
Ice caps, glaciers and permanent snow hold 24,064,000 cubic kilometres: 68.6% of the fresh water in the table.
Groundwater holds 23,400,000 cubic kilometres, and more than half of it is salty: 12,870,000 is saline and 10,530,000 is fresh.
Next: compare two storesWhere is Earth's water? Pupil worksheet
Use your browser's Print command (Ctrl+P or Command+P). The worksheet and teacher key print on separate pages; no PDF download is needed.
Name: ____________________ Date: ____________________
The USGS table
| Where the water is | Cubic kilometres |
|---|---|
| Oceans, seas and bays | 1,338,000,000 |
| Ice caps, glaciers and permanent snow | 24,064,000 |
| Groundwater, fresh and saline together | 23,400,000 |
| Fresh groundwater | 10,530,000 |
| Saline groundwater | 12,870,000 |
| Ground ice and permafrost | 300,000 |
| Lakes, fresh and saline | 176,400 |
| Soil moisture | 16,500 |
| Water in the atmosphere | 12,900 |
| Swamp water | 11,470 |
| All the world's rivers | 2,120 |
| Water inside living things | 1,120 |
Which store in the table holds the most water?
Colour the rows whose names mean frozen water. Is all of Earth's water liquid?
Which holds more water: all the world's rivers or the water in the atmosphere?
Where is most of the fresh water in the table?
Lesson and sources: https://triassicwater.com/teach/where-is-earths-water
Teacher answer key
- Oceans, seas and bays: 1,338,000,000 cubic kilometres, 96.5% of all the water the USGS table counts.
- Ice caps, glaciers and permanent snow; ground ice and permafrost. No: some of the water in the table is frozen.
- The water in the atmosphere: 12,900 cubic kilometres. All the world's rivers hold 2,120 cubic kilometres.
- In ice caps, glaciers and permanent snow: 68.6% of the fresh water in the table.
Accept equivalent careful wording. If a pupil says the table counts every drop of water on Earth, ask where the table stops. Keep the word estimate in the answer.
Sources and limits
Every number in this lesson is a row of one table, in the cubic kilometres the table itself publishes. The same rows are on the page about water inside the Earth and the page about groundwater. It is not a new measurement, and the bar diagram is a schematic that adds no claim of its own.
- USGS Water Science School — Where is Earth's Water? (global water distribution table), read . Credit: U.S. Geological Survey.
- USGS names its own source for the table, and so do we: Igor Shiklomanov’s chapter “World fresh water resources” in Peter H. Gleick (editor), 1993, Water in Crisis.
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