The Water Cycle

What makes water so unique? http://www.youtube.com/watch?v=al-do-HGuIk

Evaporation Evaporation is when heat energy from the sun causes water in puddles, streams, rivers, seas or lakes to change from a liquid to a water vapor. Evaporation –the process where a liquid, in this case water, changes from its liquid state to a gaseous state.

Transpiration Transpiration is the process by which plants lose water out of their leaves.  Transpiration gives evaporation a bit of a hand in getting the water vapor back up into the air. Transpiration –As plants absorb water from the soil, the water moves from the roots through the stems to the leaves. Once the water reaches the leaves, some of it evaporates from the leaves, adding to the amount of water vapor in the air. This process of evaporation through plant leaves is called transpiration.

Condensation Water vapor collects in clouds. As the clouds cool the water vapor condenses into water drops. This is called condensation. These drops fall to the earth as rain, snow or hail. Condensation –the opposite of evaporation. Condensation occurs when a gas is changed into a liquid.

Precipitation Precipitation is when water falls to the earth from clouds. Mainly as rain, but sometimes as snow and hail. Precipitation –when the temperature and atmospheric pressure are right, the small droplets of water in clouds.

Infiltration Infiltration is where rain water soaks into the ground, through the soil and underlying rock layers.

Accumulation Accumulation –the build-up of water in one place over a course of time.

Run-Off Run-Off –Much of the water that returns to earth as precipitation runs off the surface of the land, and flows down hill into streams, rivers, ponds, and lakes.

Run-Off Infiltration

Condensation Transpiration Precipitation Evaporation The Clouds form The movement through plants Precipitation The rain falls Evaporation The vapor rises

Carbon and Nitrogen Cycles

The Carbon Cycle

Carbon Moves From: Atmosphere to plants (C02 pulled from air to use in photosynthesis) Plants to animals (animals eat plants or other animals) Plants and animals to soils (decaying bodies release carbon into the soil) Living things to atmosphere (as you exhale, release CO2)

Concerns for Humans CO2 is a greenhouse gas that traps heat in the atmosphere. Burning fossil fuels has added 5.5 billion tons per year of carbon to the atmosphere (a 30% increase over the past 150 years) The increased Carbon is causing the planet to become warmer.

The Nitrogen Cycle 80% of Nitrogen is in the atmosphere (it is not in a form that humans can use: needs to be broken down by lightning, fire or bacteria) Animals get nitrogen to make amino acids by eating plants (when animals/plants die, decompose and return nitrogen to soil)

Concerns for Humans The use of nitrogen rich fertilizers, causes too much nitrogen to be added to waterways via runoff. Animal wastes associated with farming add more nitrogen to soil and water. Burning fossil fuels fixes nitrogen from the air. High concentrations of nitrogen in the water causes “algae blooms”: toxic to fish and shellfish.