WATER Hydrosphere Any part of the Earth that

WATER

Hydrosphere • Any part of the Earth that contains water is part of the hydrosphere – On the surface, below the surface, above the surface

Properties of Water • Structure – Made of Hydrogen and Oxygen covalently bonded • Hydrogen ends are positive • Oxygen ends are negative • Exists as a solid, liquid and gas in nature

POLAR MOLECULE – molecule that has electrically charged areas

PROPERTIES OF WATER • All properties are due to the POLARITY of water – COHESION – attraction between water molecules – ADHESION – attraction of water molecules to other molecules

WATER MOLECULES are cohesive or stick to each other because of + and - charges WATER MOLECULES are adhesive or stick to other molecules

• CAPILLARY ACTION – combined force of the attraction of water molecules to each other and to molecules of surrounding materials – This allows water to climb up material or move through any material with pores

CAPILLARY ACTION If you put a straw in water it climbs up the straw because water molecules attract to the molecules of the straw (adhesion) and pull other water molecules along also (cohesion)

• SURFACE TENSION – tightness across the surface of water. – Caused by water molecules pulling on each other (cohesion)

Surface tension allows animals to walk on water Surface tension is the reason why water forms curves shapes

• UNIVERSAL SOLVENT – substances dissolve in water because it is polar – Water molecules attract to substances of other polar molecules (adhesion) – Universal solvent – Will not dissolve nonpolar substances

• SPECIFIC HEAT – amount of heat needed to increase a certain mass of a substance by 1 degree Celsius – Water has a high specific – it heats up slowly – This is caused by the strong attraction between water molecules (cohesion)

Heat of Vaporization • Amount of heat needed to turn a liquid into a gas • Water has a high heat of vaporization because water molecules stick to each other (cohesion)

DENSITY Shows relationship between mass and volume D= Mass/Volume Units g/ml or g/cm 3 (cubed) Density of water is 1 g/ml To float in a fluid the density of the object must be less than the density of the fluid • Why would a piece of steel not float in water? • • •

FLOATING AND SINKING • Buoyancy – ability to float – Buoyant force – an upward force exerted by fluids • Opposite of gravity • Makes objects feel lighter • Objects sink if its weight is greater than the buoyant force

• To make an object sink or float you can change its density. • Example – To make a sub sink, water fills flotation tanks (increasing density) – To make a sub float, water is pumped out of tanks and air is pumped in (decreasing density)

Both objects have the same mass. The on the right floats because it takes up more space (volume) therefore displacing more water. By changing the volume its density was lowered.

Water on Earth • Water covers around 70% of the Earth's surface! • All living things need water either for body processes or shelter – Habitats – a place where an organism lives – More life in aquatic habitats (water) than terrestrial (land) – Did you know 85% of plant life is found in the ocean

Where is the water on Earth? • 97% of the water on earth is salt water (oceans, seas) – Earth mostly covered by one big ocean

• The remaining 3% is fresh water – just over ¾ (76%) of fresh water is ICE – Nearly ¼ (23%) is ground water – water found underground – The remaining 1% is in the atmosphere, lakes rivers or streams What does this look like?

How much water do we use? • Water facts: • � One toilet flush uses 5 gallons of water. • � A ten-minute shower uses 100 gallons of water. • � A ½ full bathtub takes 50 gallons of water. • � Brushing teeth takes 2 gallons of water. • � The dishwasher uses 10 gallons of water. • � The clothes washer uses 50 gallons of water.

The Water Cycle • Continuous process of water moving from the atmosphere to earth and back

• 3 major steps – Evaporation – Liquid to Gas on the surface • Transpiration – plants giving off water vapor • Water enters the atmosphere via these processes – Condensation – Gas to Liquid , water vapor cools as it rises and clumps with dust to form clouds – Precipitation – water falling back to Earth • When clouds get “heavy enough” water falls • Rain, sleet, snow or hail

• Water cycle is continuous • Renews fresh water supply • Keeps amount of water on Earth constant

Surface Water • River Systems – a river and all of its tributaries TRIBUTARIES – small river that feeds a main river • Rivers are supplied by WATERSHEDS – land area that supplies water to a river system • Watersheds are separated by DIVIDES – ridge of land (Appalachian Mts, Rocky Mts)

Know the following terms: headwaters, tributary, mouth,

Watersheds of NC

Water Underground • Water that has trickled down between particles of soil and rocks – Permeable – material that has pores, allows stuff to pass through – Impermeable – has no pores, will not allow stuff to pass thorugh

• Water Zones – Saturated zone – layer of soil or rock that is filled with water – Water Table – top of the saturated zone – Unsaturated zone – above the water table, not filled with water

• Using Groundwater – AQUIFERS – any layer of underground rock or sediment that holds water • Found above an impermeable layer • Water is constantly moving (gravity) • Provides drinking water – To use the water we drill wells • Must drill below the water table