Distribution of Earth’s Water
Materials: ★☆☆ Easy to get from supermarket or hardware store
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★☆☆ Minimal safety procedures required
Categories: Pollution and Conservation, Sustainability, Water Cycle
Alternative titles: Earth’s Fresh and Salt Water
Summary
Cups and measured amounts of water are used to visually represent how much of Earth’s water is salt water compared to fresh water, and how the fresh water is further divided among glaciers, groundwater, and surface water.
Procedure
- Fill a measuring cup with 500 mL of water to represent all of Earth’s water.
- Measure out 15 mL from the total. This represents all of Earth’s fresh water. The remaining 485 mL represents salt water, found mainly in oceans.
- Add salt and blue food coloring to the 485 mL portion to represent the oceans.
- Divide the 15 mL of fresh water into three separate cups:
- 10.3 mL into a cup labeled “Ice/Glaciers” (68.7%).
- 4.5 mL into a cup labeled “Groundwater” (30.1%).
- 0.18 mL into a cup labeled “Lakes/Rivers” (1.2%).
- Compare the amounts visually to see how little accessible fresh water exists.
Links
All the Water in the World | Water Experiments for Kids - Water Education:
📄 Distribution of Earth's Water Demonstration - Homeschool Daily: https://thehomeschooldaily.com/distribution-of-earths-water-demonstration/?srsltid=AfmBOoouuBJ0fEOYpx94aCt9FPKOzIkPRLDAGZCWm8XNUZjozNEsYIBL
Variations
- Use larger or smaller volumes (e.g., 1 liter instead of 500 mL) to scale the demonstration for different class sizes.
- Use colored dyes for each category (blue for lakes/rivers, green for groundwater, white for glaciers).
- Extend the demo by showing desalination or water filtration methods.
Safety Precautions
- Handle food coloring carefully to avoid stains.
- If using glass containers, handle with care to avoid breakage.
Questions to Consider
- Where is most of Earth’s fresh water stored? (In ice and glaciers.)
- Which type of fresh water is easiest for humans to access? (Lakes and rivers, but it makes up only 1.2% of fresh water.)
- Why is it important to conserve fresh water? (Because only a tiny fraction of Earth’s water is readily usable by people, plants, and animals.)
- How might technology help us use more of Earth’s water supply? (Through desalination, groundwater extraction, or improved water recycling.)