The Water Cycle Learning Objectives: To be able to identify the steps in the water cycles Keywords: water cycle, cooling, clouds, transpiration, percolation, precipitation, condensation, water vapor, evaporation, ocean, surface run-off

The Biogeochemical Cycles There are 3 cycles of matter called the biogeochemical cycles. These include: 1. The water cycle 2. The carbon cycle 3. The nitrogen cycle

The Water Cycle The water cycle describes how water moves on, above, or just below the surface of our planet. Water molecules move between various locations - such as rivers, oceans and the atmosphere - by specific processes. Water can change state.

1.Water Cycle The movement of water between the atmosphere and Earth.  It includes: Evaporation, Condensation, Precipitation, Surface Runoff, Transpiration and Perspiration. 2.Condensation The process where water vapor changes from a gas to liquid water. 3.Transpiration When plants release water through pores in their leaves back into the atmosphere. 4.Percolation Water filtering down through the soil due to gravity 5.Cloud  Millions of tiny water droplets or crystals.  They form when water vapor in the air condenses to form liquid water or ice crystals.  They can only form when dust particles and cool air are present** 6.Evaporation The process where liquid water changes to a gas as water vapor. 7.Surface Runoff  Water that cannot be absorbed into the surface (the ground is too dense) but runs along it. 8.Water Vapor When water is in the gas state. 9.Precipitation Any form of water that falls from clouds and reaches Earth's surface.  Rain, snow, or hail

Water Cycle

The Stages 1) Evaporation Energy from the Sun heats the Earth’s surface and water evaporates from oceans, rivers and lakes. The warm air rises, carrying water vapor with it. 2) Transpiration Transpiration from plants releases water vapor into the air.

3) Condensation The moist air cools down as it rises. Water vapor condenses back into liquid water, and this condensation process produces clouds. 4) Precipitation As the water droplets in the cloud get bigger and heavier, they begin to fall as rain, snow and sleet. This is called precipitation

The Carbon Cycle Learning Objectives: To be able to identify the steps in the carbon cycle Keywords: carbon cycle, respiration, combustion, photosynthesis, fossil fuel

Definitions Carbon cycle: the process by which carbon moves from the atmosphere into the Earth and its organisms and then back again. Respiration: the process by which cells use oxygen to break down carbohydrates and obtain energy Combustion: the process of burning something. Photosynthesis: the process in which green plants use energy from the sun to transform water and carbon dioxide into oxygen and carbohydrates. Fossil fuel: a natural fuel such as oil, coal or gas, formed in the past from dead organisms.

The carbon cycle Carbon is passed from the atmosphere, as carbon dioxide, to living things. It is then passed from one organism to the next in complex molecules, and returned to the atmosphere as carbon dioxide again. This is known as the carbon cycle.

The Stages

The Stages

The Stages

The Stages

The Stages Removing carbon dioxide from the atmosphere Plants use carbon dioxide from the atmosphere for photosynthesis. The carbon becomes part of complex molecules in the plants, such as proteins, fats and carbohydrates.

The Stages 2) Passing carbon from one organism to the next When an animal eats a plant, carbon from the plant becomes part of the fats and proteins in the animal. 

The Stages 3) Returning carbon dioxide to the atmosphere Carbon dioxide is released to the atmosphere through respiration by animals, plants and microorganisms. It is also released by the combustion of wood and fossil fuels (such as coal, oil and natural gas).

The Stages 4) Decomposition or decay also releases carbon dioxide. This process happens faster in warm, moist conditions with plenty of oxygen because it involves microorganisms.

The Nitrogen Cycle Learning Objectives: To be able to identify the steps in the nitrogen cycle Keywords: nitrogen cycle, nitrogen fixation, denitrification

Definitions Nitrogen cycle: processes by which nitrogen passes from air to soil to organisms and back to air or soil. Nitrogen fixation: the conversion of nitrogen  in the atmosphere into a form that plants can use Denitrification: the conversion of nitrates in soil into nitrogen gas that goes into the atmosphere

The Nitrogen Cycle Nitrogen compounds found in cells include proteins. Nitrogen from the air is converted into a form that plant roots can absorb. It forms part of nitrogen compounds in the plants, and is then passed from one organism to the next. It is returned to the atmosphere as nitrogen gas. This is the nitrogen cycle.

The Stages

The Stages

The Stages

The Stages

The Stages

Nitrogen About 78% of the air is nitrogen gas. But plants can not use it to make proteins straight from the air. It must be converted into a nitrates which is a combination of nitrogen and oxygen. 

Stage one - fixation Nitrogen-fixing bacteria in the roots of plants are able to do this.  Lightning can also convert nitrogen gas into nitrates.

Stage two - absorption into roots and used by plants Plants absorb nitrates from the soil and use these to make proteins.

Stage three - moving along food chains and excretion When an animal eats a plant, nitrogen from the plant’s proteins becomes proteins in the animal. Nitrogen is also passed from one animal to another by feeding.

Stage four - death of animals Decomposers break down urea (urine), faeces (poop) and dead bodies. This results in nitrogen being returned to the soil, which the bacteria can convert into nitrates for plants to absorb.

Stage five - release into atmosphere Denitrifying bacteria in the soil break down nitrates and return nitrogen gas to the air.