A variety of factors affect water density, more water sinks, setting up convection currentsEx 1: Oil and WaterEx 2: Styrafoam cup is less dense than a ceramic cupHow much Density a susbstance has can be measured when it floats to the surface
Surface Currents
Surface currents are currents that occur near the surface of the oceanEx1: Warm currentsEx2: Cool currentsSurface currents happen near or at the surface of the ocean
A process in which deep, cold water rises toward the surfaceThere are upwellings and downwellingsUpwellings are vertical water movements powered by densityEx1: Thermohaline currents are constant movements of surface and verticle currents across the globe driven by temapture and silinity
The Coriolis Effect 
A phenomenon that causes fluids like water and air, to curve as they travel across or above earth’s surfaceThe coriolis effect can explain why some hurricanes go clockwise and some go counter clockwiseEx1: HurricaneEx2: Movement of weather patterns
Deep Ocean Currents
Deep ocean currents are currents driven by density and temapture gradientsEx1: Thermohaline CirculationDeep ocean currents are warmed at the equator then transported up to the poles to warm the water tempatures up there.
Water Cycle 
The cycle of processes which water circulates between earth’s oceans, atmosphere and land. involving precipiatation as rain and snow, drainage in streams and rivers, and return to the atmosphere by evaporation and transpiritaionEx1: Percipiataion is when it rains/snows which is a a part of the water cycleEx2: Evaporation is when the rain/snow turns into water particles and evaporatesThe water cycle helps water circulate water
Ground Water
Water held underground in the soil or in pores and crevices in rockEx1: creeksEx2: StreamsUsually Ground Water is in forest
Surface Water
Water that collects on the surface of the groundEx1: PondEx2: LakeSurface Water collects at the surface aroudn pounds, Lakes
Ground water cross section
Water table in a cross section of landEx1: Surface Water, Unsaturated waterEx2: Water Table, Ground WaterThe water table is the top level of groundwater.
A shaft sunk into the ground to obtain water, oil, or gasEx1: BoreholeEx2: SpringShe drew water from the well
Aquafier Depeltion
A body of permeable rock that can contain and transmit groundwaterEx1: ReplenishableEx2: Non replinshableMant countries like China, India and the united states are struggling with aquafiers
Salt water intrusion
Saltwater intrusion is the movement of saline water into freshwater aquifersEx1: Saltwater Saltwater intrusion occurs naturally to some degree in most coastal aquifer
A barrier constructed to hold back water and raise its levelEx1: Barrier Ex2: Wall Dams can be used for hydroelectricty 
Dam removal
Dam removal is the process of removing out-dated, dangerous, or ecologically damaging dams from river systems. 
Dam removal suppsoedly helps ecosystems who are affected by the dam
Agriculture effects on freshwater
Agricutlure effects freshwater because agriculture accounts for 70% of our fresh water useEx1: Runoff fromEx2: Applictaion of pesticides
recreational effects of freshwater
Recreational effects on freshwater include building buildingsEx1: Climate changeEx2: Global WarmingRecreational buldings can effect freshwater habitats/ecosystems drastically
Non point source pollution
Non point source pollution is pollution comes from many diffuse sourcesEx1: Excessive fertilizersEx2: Urban runoffOil grease is an example of non point source pollution
Point source pollution 
Point source pollution is any single identifiable source of pollution from which pollutants are discharged, such as a pipe, ditch, ship or factory smokestackEx1: Water Quality Ex2: Industrial plantsIndustrial plants release chemicals into the air which is when point source pollution happens
Primary waste water treatment
Primary waste water treatments are processes are designed to achieve improvements in the quality of the wastewaterEx1: Suspend SolidsEx2: Biodegradable Organics Primary waste water treatements are closesly related to expectations set for effluent quality 
Secondary waste water treatement
Secondary treatment is a treatment process for wastewater (or sewage) to achieve a certain degree of effluent qualityEx1: Sewege treatement Secondary treatment remove dissolved and suspended organic compounds
Tertiary waste water treatement
Tertiary treatment is the final cleaning process that improves wastewater quality before it is reusedEx1: Patheogenic bacteriaEx2: Nutrients Tertiary treament helps us make sure our water is completely clean
Sludge is a thick, soft, wet mud or a similar viscous mixture of liquid and solid components, especially the product of an industrial or refining processEx1: MudEx2: MireSludge can be any type of ooze forming a deposit at the bottom of bodies of water