Saving Clean Water - Second Grade Science
Water is essential for all living things. Our bodies are over 60 percent water, and humans cannot survive for more than a few days without clean water to drink. Although planet Earth looks like a water-filled planet from space, less than one percent of all water on Earth is liquid freshwater available for humans, land animals, and plants to drink and use! With human populations growing and pollution threatening waterways, saving clean water through conservation is one of the most vital responsibilities of second grade scientists.
Earth's Freshwater Scarcity
Many people turn on a bathroom faucet and assume water is unlimited because clean water pours freely from the tap. However, freshwater is surprisingly scarce.
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| THE 100-DROP WATER BUCKET MODEL |
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| Imagine ALL the water on Earth fits into a 100-drop bucket: |
| - 97 Drops = Salty Ocean Water (Cannot drink or water crops!) |
| - 2 Drops = Solid Glacier Ice locked at the North & South Poles! |
| - 1 DROP = All the drinkable liquid freshwater on Earth! |
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The Water Cycle: Nature Cleans and Recycles
Earth has the exact same amount of water today that it had during the age of the dinosaurs! Nature cleans and recycles water continuously through the water cycle: evaporation turns surface water into vapor, condensation builds clouds, and precipitation brings fresh rain and snow down to refill lakes and aquifers.
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| THE WATER CYCLE REVIEW |
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| +-------> CONDENSATION (Clouds) ------>+ |
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| EVAPORATION PRECIPITATION |
| (Sun warms water) (Rain, Snow) |
| ^ | |
| +<------- RUNOFF & COLLECTION <--------+ |
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How Humans Use Water
In modern homes, families consume dozens of gallons of treated, drinkable water every single day for tasks that do not even require drinking water: Flushing Toilets: The single largest indoor water use (up to 3 to 5 gallons per flush in older toilets). Showering and Bathing: A typical 10-minute shower uses 25 to 50 gallons of water. Washing Clothes and Dishes: Washing machines use 15 to 40 gallons per load. Outdoor Lawn Sprinklers: Lawns and gardens consume up to half of all residential water in the summer!
Water Conservation: Smart Habits at Home
Water conservation means using less water and avoiding wasting clean water through careless habits. Small changes in daily habits add up to thousands of gallons saved each year.
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| WATER-SAVING HABITS AT HOME |
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| HABIT WATER SAVED |
| Turn off tap while brush Saves 8 gallons of water every day! |
| Take a 5-minute shower Saves 25 gallons compared to a bath! |
| Fix a leaky dripping tap Saves 3,000 gallons of clean water/year! |
| Water garden with rain bbl Saves gallons of purified city tap water!|
| Run full dishwasher loads Saves water compared to washing by hand! |
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The Leaky Faucet Test
A faucet that drips just one tiny drop per second might seem harmless, but over a year that single dripping faucet wastes more than 3,000 gallons of purified drinking water! Placing a new rubber washer inside the faucet stops the leak and saves precious water.
Preventing Water Pollution
Conserving water also means protecting the water we have from chemical contamination. Once a river, lake, or groundwater aquifer becomes polluted, it is expensive and difficult to clean.
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| PREVENTING WATER POLLUTION |
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| - NEVER POUR CHEMICALS DOWN STORM DRAINS: Storm drains connect |
| directly to local streams and rivers without water treatment! |
| - SCOOP PET POOP: Pet waste carries harmful bacteria into runoff. |
| - LIMIT LAWN FERTILIZERS: Excess chemical fertilizer washes into |
| ponds, creating toxic green algae blooms that suffocate fish. |
| - DISPOSE OF MEDICINES PROPERLY: Never flush old pills down toilets.|
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Engineering Inventions for Water Conservation
Modern civil engineers design innovative technologies to conserve water: Low-Flow Aerators: Small metal screens screwed onto faucet heads that mix air bubbles into the water stream, cutting water volume by 50 percent while maintaining high water pressure! Dual-Flush Toilets: Have two flush buttons—one button uses a small amount of water for liquid waste, while the other uses slightly more for solid waste. Rain Barrels: Barrels placed beneath roof rain gutters to collect falling rainwater for outdoor gardening.
Chapter Review Exercises
Question 1: Out of all the water on Earth, why is less than one percent available for humans and land animals to drink?
Question 2: Name two simple water-saving habits that a second-grade student can do at home to conserve clean water.
Question 3: Why should soapy water, motor oil, or garden fertilizers never be dumped into outdoor street storm drains?
Question 4: How does a low-flow faucet aerator save water without reducing water pressure?
Solutions and Explanations
Solution 1: Less than one percent is available because roughly 97 percent of Earth's water is salty ocean water that is unsafe to drink, and about two percent of the remaining freshwater is frozen solid in polar ice sheets and mountain glaciers.
Solution 2: Two simple habits are turning off the water faucet while brushing your teeth (saving up to eight gallons per day) and taking shorter five-minute showers instead of filling deep bathtubs.
Solution 3: Street storm drains do not lead to municipal water treatment plants; they flow directly into local streams, rivers, and ponds. Dumping chemicals, pet waste, or oil into storm drains poisons fish, damages aquatic ecosystems, and contaminates drinking water supplies.
Solution 4: A low-flow aerator mixes tiny air bubbles into the rushing water stream. This keeps the water spray feeling full, strong, and pressurized while cutting the actual volume of water flowing through the faucet in half.