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Where can the freshwater be found?¾ Freshwater is Frozen Solid in ice caps and glaciers ¼ Freshwater is Liquid underground
A tiny fraction is in lakes & rivers
A smaller fraction is water vapor in the atmosphere
What is the Water Cycle?
Definition: The continuous movement of water from Earth’s surface into the atmosphere and then back again!
The water cycle is powered by the Sun.
What is Evaporation?
When water changes from liquid to water vapor (liquid to gas)Evaporation comes from:
• plants• lakes• oceans
What happens after water evaporates?
Condensation!
As air and water vapor rise, they cool to form clouds
(gas to liquid)
What happens when the droplets get too large to stay in the clouds?They fall as Precipitation –water that falls from clouds as
RainSnowSleetHail
What happens to water that falls to the ground?
Accumulation- collection of water
•Runoff – water flows across the land into streams, rivers, or oceans
•Groundwater – water soaks into the ground
How can we get to the water so we can use it everyday?
• Springs can form & water bubbles out naturally
• Wells provide access to Aquifers that have drinking water – Wells can be mechanically or hand
pumped– In Artesian Wells, water rises
because of pressure in an Aquifer
How is water used?• In your home• Industry & Transportation• Agriculture• Recreation
Why is it important to conserve water?
Remember…we have more saltwater on Earth than freshwater!
So, why can’t we just drink sea water?
Because it tastes yucky! That’s why!
Why does it taste yucky?Because it has lots of salt…
• Salinity – the amount of salt dissolved in water (NaCl)
• Average salinity of the ocean is 3.5%–If you boiled 1kg of ocean water in a pot until all water was gone, you’d be left with about 35g of salt left in the pot!
Where do the salts and minerals come from?
• Salt and minerals that are in the ocean come mostly from dissolved rocks, and soil that is brought to the oceans from rivers
• Volcanoes also provide salts to the oceans.
What does salt do to the ocean water?
• Lowers the freezing point of water
• It makes seawater more dense
• Greater buoyancy – you float higher in some ocean water
Temperature of Ocean Water
• Closer to the equator = warmer water
• Temperature decrease as you go deeper
• Density & Pressure increase as you go deeper
Dissolved Gases in Ocean Water:
Oxygen Carbon Dioxide
Sea plants & creatures use these gases to survive
• All of the oceans are connected, and essentially one big ocean.
• We have made imaginary boundaries to break up this ocean, and currently we have 5 different oceans.
World’s Oceans
Main features of the ocean floor:(F) Continental shelf (C) Abyssal Plain
(A) Continental slope (B) Seamount(E) Volcanic islands (G) Ocean trench
(D) Mid-ocean ridge