The Global Water Crisis
Investigate why billions lack clean water, analyse the data, and speak up for change.
Subjects Connected
Science
Water cycle, contamination, filtration methods, water testing
Maths
Percentages, statistics, per-capita calculations, interpreting data
English
Persuasive speech writing, rhetorical techniques, presenting arguments
Finnish phenomenon: "Why don't all people have clean water?"
The Big Question
"Why don't all people have access to clean water, and what can we do about it?"
In this project, you will explore the science of water, analyse real-world data on water access, and write a persuasive speech calling for action.
Science: Water on Earth
The Water Cycle
Water moves continuously between the Earth's surface and atmosphere in a process called the water cycle. The same water that exists on Earth today has been recycled for billions of years.
Evaporation
Sun heats water; it turns to vapour and rises
Condensation
Vapour cools and forms clouds (tiny water droplets)
Precipitation
Water falls as rain, snow, sleet, or hail
Collection
Water gathers in rivers, lakes, oceans, and underground
Clean vs Contaminated Water
Clean water looks clear, has no smell, and is free from harmful bacteria, chemicals, and parasites. Contaminated water can contain:
Biological
Bacteria (E. coli), viruses, parasites that cause cholera, dysentery, typhoid
Chemical
Pesticides, industrial waste, heavy metals like lead and mercury
Physical
Sediment, dirt, litter, microplastics that make water unsafe
Filtration Methods
Water filtration removes contaminants to make water safe for drinking:
Physical filtration (sand/gravel)
Removes large particles and sediment as water passes through layers of gravel, sand, and fine material.
Activated carbon
Carbon absorbs chemicals, chlorine, and some organic compounds, improving taste and safety.
UV treatment / boiling
Kills bacteria and viruses. Boiling water for at least 1 minute makes it safe from most biological contaminants.
Think About It (3-2-1 Bridge)
Before you continue, write down:
- 3 thoughts about the water crisis
- 2 questions you have
- 1 analogy or comparison (e.g. "The water crisis is like...")
Come back to these at the end and see how your thinking has changed.
Maths: Water by the Numbers
Earth's Water: A Shocking Breakdown
Earth is called the "Blue Planet" because 71% of its surface is covered with water. But how much is actually usable?
Less than 1% of all water on Earth is available fresh water for humans, animals, and plants.
Water Usage: Per-Capita Comparisons
Different countries use vastly different amounts of water per person per day:
| Country | Litres per person per day | Access to clean water |
|---|---|---|
| United States | 375 | 99% |
| Australia | 340 | 99% |
| United Kingdom | 150 | 99% |
| China | 86 | 95% |
| India | 45 | 88% |
| Mozambique | 10 | 56% |
| Ethiopia | 15 | 57% |
Worked Example: Comparing Usage
How many times more water does an American use compared to someone in Mozambique?
375 ÷ 10 = 37.5 times more
If everyone in the US (330 million people) reduced usage by just 10%, how much water would be saved per day?
330,000,000 x 375 x 0.10 = 12.375 billion litres per day
Think About It (Headlines Routine)
Look at the data table above. If you were a journalist, what headline would you write?
- Write a headline that captures the most important story in this data.
- Write a headline from the perspective of someone in Mozambique.
- Write a headline from the perspective of someone in the US.
- How do the headlines differ? Why?
English: Writing a Persuasive Speech
A persuasive speech is different from a written essay — it is designed to be heard. It uses emotion, rhythm, repetition, and rhetorical questions to move the audience to action.
Rhetorical Techniques
Rhetorical Question
"How can we call ourselves civilised when 2 billion people lack safe water?"
Rule of Three
"Clean water is a right, a necessity, and a matter of survival."
Repetition (Anaphora)
"Every child deserves clean water. Every family deserves clean water. Every community..."
Statistics as Evidence
"2.2 billion people — nearly 1 in 3 humans — do not have safely managed water at home."
Emotive Language
"Children are dying from preventable diseases because they have no choice but to drink contaminated water."
Call to Action
"We must act now. Donate, volunteer, raise your voice. The time for change is today."
Speech Structure
- Hook: Start with a shocking fact or rhetorical question to grab attention.
- The Problem: Explain the water crisis using data and real examples.
- Why It Matters: Connect the issue to the audience — why should they care?
- The Solution: What can be done? Be specific about actions.
- Call to Action: End powerfully — what do you want the audience to DO?
Think About It (Red Light, Yellow Light)
Evaluate the following claims about water:
- Red light (stop — unreliable): "Water problems are just because people are lazy."
- Yellow light (proceed with caution): "Technology alone can solve the water crisis."
- Green light (go — reliable): "Investment in water infrastructure saves lives."
Why is it important to evaluate claims before using them in a speech?
At-Home Experiment: Build a Water Filter
Build a simple water filter to see how physical filtration works. Important: This is for observation only — do NOT drink the filtered water.
What You Need:
- A large plastic bottle (cut in half)
- Cotton wool or a coffee filter
- Sand (fine)
- Gravel or small stones
- Activated charcoal (from a pet shop, optional)
- Dirty water (mix soil/dirt into water)
- A glass or jar to collect filtered water
Turn the top half of the bottle upside down and place it inside the bottom half (like a funnel).
Layer from bottom to top: cotton wool, charcoal (if using), fine sand, coarse sand, gravel.
Slowly pour the dirty water through the top. Observe what comes out the bottom.
Compare the filtered water to the original dirty water. What differences do you notice?
Remember: This filter removes visible particles but NOT bacteria or chemicals. Real water treatment requires UV, chlorine, or boiling to kill germs.
Key Vocabulary
Water Cycle
The continuous movement of water through evaporation, condensation, precipitation, and collection.
Contamination
The presence of harmful substances (bacteria, chemicals, sediment) in water that make it unsafe.
Per Capita
Per person. Used in statistics to compare amounts fairly between populations of different sizes.
Percentage
A number expressed as a fraction of 100. Used to compare proportions (e.g. 97.5% of water is salt water).
Rhetoric
The art of using language persuasively, including techniques like repetition, rhetorical questions, and the rule of three.
Filtration
The process of removing impurities from water by passing it through a filter (sand, carbon, membrane).
Activities & Investigations
Water Audit (Maths + Science)
Track your household water usage for 3 days. Record how much you use for drinking, showers, toilets, dishes, laundry. Calculate your daily per-capita usage and compare it with the data in the table above.
Build and Test a Water Filter (Science)
Follow the at-home experiment above. Record your observations. Try different layer orders — does the sequence matter? Write up your experiment with hypothesis, method, results, and conclusion.
Data Analysis Challenge (Maths)
Using the per-capita data: If Australia (26 million people) reduced usage by 15%, how many litres would be saved daily? If that water were shared equally among the 57 million people in Ethiopia without clean water, how many litres per person would they receive?
Write and Deliver a Speech (English + All Subjects)
Write a 2-3 minute persuasive speech about the global water crisis. Use at least 3 rhetorical techniques and include specific data from your maths work. Practice delivering it and present to your class or family.
Knowledge Check
Test your understanding across all three subjects.
Question 1 Maths
What percentage of Earth's water is fresh water available for human use?
Question 2 Science
In the water cycle, what process turns liquid water into water vapour?
Question 3 Maths
A person in the US uses 375 litres per day. A person in Mozambique uses 10 litres. How many times more water does the American use?
Question 4 Science
Which of these can a simple sand and gravel filter remove from water?
Question 5 English
Which rhetorical technique is used in: "Clean water is a right, a necessity, and a matter of survival"?
Key Concepts Summary
- ● Science: The water cycle continuously recycles water. Less than 1% of Earth's water is usable fresh water. Filtration removes physical particles but UV/boiling is needed to kill germs.
- ● Maths: Per-capita comparisons reveal massive inequality in water access. Percentages help us understand proportions. Simple calculations can show the impact of small changes at scale.
- ● English: Persuasive speeches use rhetorical techniques (rule of three, repetition, rhetorical questions) combined with data to move audiences to action.
- ● Connection: Solving the water crisis requires understanding the science, analysing the data, and communicating urgently — all three skills working together.