2. Transpiration 1. Evaporation 1. Evaporation 5 ...

5. Transportation 4. Condensation

1. Evaporation

5. Transportation

6. Precipitation

4. Condensation 7. Deposition

3. Sublimation 2. Transpiration

6. Precipitation

9. Snowmelt Runoff

9. Surface Flow

1. Evaporation

9. Surface Flow

10. Plant Uptake 9. Groundwater Flow

8. Infiltration 8. Percolation

Diagram source: NOAA National Weather Service Jet stream

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Name________________________________________ Create a study guide to help YOU learn the processes involved in the water cycle. You may choose to take note, create a graphic organizer, or something different. Do not copy definition word-for-word or draw the same diagram you have been given. The guide must be made by you to be useful to you. Include these processes: evaporation, condensation, transpiration, transportation, precipitation, infiltration, percolation, runoff, sublimation, deposition.

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The Global Water Cycle

The water cycle, sometimes called the hydrologic cycle, describes the movement of water over, above and below the Earth's surface.

The water cycle is not just about how it rains and snows.

Water can easily change between any of its three states: gas (vapor), liquid and solid (ice). This is important for a couple of reasons:

1.The way water moves between all three phases is a powerful vehicle for rearranging Earth's energy budget. The energy budget describes how the incoming energy from the sun is used and returned to space. If incoming and outgoing energy are in balance, the earth's temperature remains constant. The energy balance drives the weather and life on earth.

2.The total movement of water by precipitation, infiltration, transpiration, runoff and subsurface flow redistributes water around the globe.

Water covers about three-quarters of Earth's surface and is a necessary element for life. During their constant cycling between land, the oceans, and the atmosphere, water molecules pass repeatedly through solid, liquid, and gaseous phases, but the total supply remains fairly constant. A water molecule can travel to many parts of the globe as it cycles.

Water vapor redistributes energy from the sun around the globe through atmospheric circulation. This happens because water absorbs a lot of energy when it changes its state from liquid to gas. Even though the temperature of the water vapor may not increase when it evaporates from liquid water, this vapor now contains more energy, which is referred to as latent heat. Atmospheric circulation moves this latent heat around Earth, and when water vapor condenses and produces rain, the latent heat is released.

Very little water is consumed in the sense of actually taking it out of the water cycle permanently, and unlike energy resources such as oil, water is not lost as a consequence of being used. However, human intervention often increases the change of water out of one store of water into another, so it can reduce the stores of water that are most usable. For example, pumping groundwater for irrigation depletes aquifers by transferring the water to evaporation or river flow. Our activities also pollute water so that it is no longer suitable for human use and is harmful to ecosystems.

The hydrologic cycle is related to cycles in other systems because rainfall erodes and weathers rock. Weathering breaks down rocks into gravel, sand, and sediments, and is an important source of key nutrients such as calcium and sulfur. Estimates from river outflows indicate that some 17 billion tons of material are transported into the oceans each year. On average, Earth's surface weathers at a rate of about 0.5 millimeter per year. Actual rates may be much higher at specific locations and may have been accelerated by human activities, such as emissions from fossil fuel combustion that make rain and snowfall more acidic. ()

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You are probably familiar with evaporation, condensation, and precipitation as part of the hydrologic cycle, but sublimation and deposition may be new concepts for you.

A quick review ?

Evaporation is the process by which water changes from a liquid to a gas or vapor. Evaporation is the primary pathway that water moves from the liquid state back into the water cycle as atmospheric water vapor.

Condensation is the process by which water vapor in the air is changed into liquid water.

Condensation is crucial to the water cycle because it is responsible for the formation of clouds. It is the opposite of evaporation. Precipitation is water released from clouds in the form of rain, freezing rain, sleet, snow, or hail. It is the primary connection in the water cycle that provides for the delivery of atmospheric water to the Earth. Most precipitation falls as rain.

Other terms that you may remember ?

Transportation - the movement of water through the atmosphere, specifically from over the oceans to over land. Some of the earth's moisture transport is visible as clouds, which themselves consist of ice crystals and/or tiny water droplets. Clouds are moved from one place to another by wind.

Transpiration - the process by which moisture is carried through plants from roots to small pores on the underside of leaves, where it changes to vapor and is released to the atmosphere. Transpiration is essentially evaporation of water from plant leaves.

Infiltration - the process by which water on the ground surface enters the soil. Percolation - the movement of water though the soil, and its layers, mostly by gravity. Runoff - When too much rain falls onto the ground and the soil becomes completely

infiltrated, the extra water is runoff. Gravity pulls runoff directly downhill.

Sublimation is the conversion between the solid and the gaseous phases of matter, with no intermediate liquid stage. For those of us interested in the water cycle, sublimation is most often used to describe the process of snow and ice changing into water vapor in the air without first melting into water.

Sublimation occurs more readily when certain weather conditions are present, such as low relative humidity and dry winds. Sublimation also occurs more at higher altitudes, where the air pressure is less than at lower altitudes. Energy, such as strong sunlight, is also needed. If I was to pick one place on Earth where sublimation happens a lot, I might choose the south face of Mt. Everest. Low temperatures, strong winds, intense sunlight, very low air pressure--just the recipe for sublimation to occur. ()

Sublimation occurs most easily when pressure is low because the atoms have less resistance when trying to expand.

The opposite of sublimation is deposition, where a gas turns directly into a solid. In the case of water, vapor changes directly into ice--such a snowflakes and frost.

Clouds consist of water vapor or the gaseous state of water (H2O). In cold weather, the conditions are right for the vapor to turn directly into solid ice crystals.

Deposition occurs most easily when pressure is high because the pressure makes it easier for atoms to come closer together to form a solid.

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