Water: Our Most Important Natural Resource

Water: Our Most Important Natural Resource © The GlobalEd 2 Project

Essential Questions: • How much of our planet is covered by water? • Why is fresh water so important? • How much fresh water is on earth? • So, why can’t we just drink sea water? © The GlobalEd 2 Project

Enduring Understandings: • ~70% of the Earth’s surface is covered by water. • ~70% of the human body is made up of water; fresh water is essential for the survival of all ecosystems; a person can only live without water for ~2-4 days; but can live without food for weeks. • There is a limited amount of fresh water on Earth. • The high concentration of salt in seawater can lead to heart failure and even death. © The GlobalEd 2 Project

Types of Water • Salt water (contains ~ 3.5% NaCl) Major sources – oceans, seas *~ 97% of Earth’s water is salt water • Fresh Water (contains ~ < 1% NaCl) Major sources – ponds, lakes, rivers, streams; precipitation from the atmosphere, as mist, rain or snow © The GlobalEd 2 Project

Fresh Water • Only ~ 2.75% water on Earth is fresh water! • ~ 2/3 of that is frozen in glaciers • ~ 1/4 is groundwater • Only ~ 0.005% is surface water * Hence, less than 1% is fresh water that we can actually use • Fresh water lakes (i.e., Lake Baikal in Russia and the Great Lakes in North America), contain 7/8 of this fresh surface water © The GlobalEd 2 Project

Interpreting: Read the following sailor’s poem; explain the author’s meaning. “Water, water, everywhere, And all the boards did shrink; Water, water, everywhere, Nor any drop to drink." (fromSamuel Taylor Coleridge's The Rime of the Ancient Mariner) © The GlobalEd 2 Project

Water: Our Most Important Natural Resource

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