What is project learning in the water cycle?
Project learning means you learn by doing a real task from beginning to end, not only by reading. In a water cycle project you study how water moves in your own place: how much rain falls, how much water dries up, where the rest goes.
You learn science (the water cycle), maths (measuring, adding, charts), and skills (planning, team work, explaining your result).
The water cycle in one minute
The Sun heats water in seas, rivers and soil. Water turns to vapour (evaporation). Vapour rises, cools and becomes tiny drops that form clouds (condensation). Drops grow heavy and fall as rain (precipitation). Rain runs into rivers, soaks into soil, and goes back to the sea. Then it starts again.
How to run the project: five steps
- Question. Make it clear and measurable. Example: "Does more rain fall than water evaporates in our town in one month?"
- Plan. List tools, who does what, when to measure (same time every day), and how to write the numbers.
- Measure. Use a rain gauge for rain. Use a tray with a known water level for evaporation.
- Record. Write in a table, then draw a bar chart. Add notes: cloudy, sunny, windy.
- Conclude and share. Say what the numbers show, what surprised you and what you would change. Show the class.
Simple tools: rain gauge and evaporation tray
Rain gauge. Cut a plastic bottle so it has straight sides. Put it in an open place away from trees and roofs. Stick a ruler (in mm) on it. After rain, read the height of the water. 1 mm of rain means 1 litre of water on every square metre of ground.
Evaporation tray. Put 20 mm of water in a shallow tray. After a day, measure how much the level went down. Keep it in the Sun, away from rain (or cover it when it rains).
Reading your results
Compare rain and evaporation. Difference = rain − evaporation. If it is positive, the place gains water; if negative, it loses water. Look for patterns: do sunny days have more evaporation? Are rainy days cooler? Be honest if your result is surprising; a small mistake in measuring is also a lesson.
Try it: a one-week project
For 7 days at 5 pm, read your gauge and tray, write the two numbers, and empty the gauge. At the end draw two bars for each day and write one sentence: "In my place this week, ..."
Key formulas and definitions
- Difference = rain − evaporation (in mm)
- 1 mm of rain = 1 litre of water per square metre
- Total rain for the week = sum of daily readings
- Average per day = total ÷ number of days
- Steps: Question, Plan, Measure, Record, Conclude
Worked examples
1. Rain over 5 days is 12, 4, 0, 20 and 9 mm. What is the total rain?
12 + 4 + 0 + 20 + 9 = 45 mm.
2. What is the average rain per day for the same 5 days?
45 ÷ 5 = 9 mm per day.
3. On one day rain was 12 mm and evaporation was 5 mm. What is the difference and what does it mean?
12 − 5 = +7 mm. The place gained 7 mm of water that day.
4. A garden of 10 m² gets 8 mm of rain. How many litres fall on it?
1 mm = 1 litre per m². So 8 × 10 = 80 litres.
5. An evaporation tray starts at 20 mm and is 14 mm after one sunny day. How much evaporated?
20 − 14 = 6 mm.
Common mistakes
- Measuring at different times each day, so the results cannot be compared.
- Placing the rain gauge under a tree or roof edge, where it catches drips or no rain.
- Forgetting to empty the gauge after each reading, so rain gets counted twice.
- Writing a conclusion that is not supported by the numbers.