What Goes Around Comes Around! Cycles in Nature

Cycles in Nature The Water Cycle The Carbon Cycle The Nitrogen Cycle 2/17/2019

Watered Down! (Precipitation) Any type of water that falls to the Earth from the clouds is called precipitation. There are four main types of precipitation: rain, snow, sleet, and hail. In Houston, we get about 45 inches of precipitation each year. Most of this precipitation evaporates back into the air. About 10-12 inches of that precipitation runs off the land into lakes, streams, bayous or ponds. Some of this water also soaks into the ground. 2/17/2019

Soak It Up! (Infiltration, Percolation) Ground Water Soak It Up! (Infiltration, Percolation) Infiltration or percolation happens when water soaks into the ground. It moves underground between layers of rock and soil. Some of this water is also soaked up by the roots of plants. Some of the water percolates down into the soil to a level that is filled with water. This water is called ground water. The very top of this layer filled with ground water is called the water table. 2/17/2019

Fill ‘er Up! (Accumulation) Oceans or Lakes Precipitation that does not soak into the ground or evaporate into the air can accumulate in oceans, streams, lakes, and bayous. A great deal of the precipitation that falls on the Earth accumulates in the oceans. Oceans cover about 75% of the Earth’s surface. 2/17/2019

Up Into the Air! (Evaporation) Land Oceans or Lakes Up Into the Air! (Evaporation) Warmth from the sun causes water from lakes, streams, ice, and the ground to change into water vapor in the air. This process is called evaporation. Almost all of the precipitation that falls from the sky (80 percent) goes right back into the air because of evaporation. The remaining water runs off the land into various bodies of water or soaks into the ground to become ground water. 2/17/2019

Don’t Sweat It! (Transpiration) Transpiration occurs when plants give off water vapor through tiny pores in their leaves. This is the plant’s way of getting rid of waste, just like people and animals sweat when they’re hot! This water vapor evaporates into the air and is stored in the atmosphere until it condenses to become clouds and then, precipitation. 2/17/2019

Cool It Down! (Condensation) Water Vapor Water vapor (water in its gaseous form) stays in the air until it cools down and changes back to water. This process is called condensation. The water vapor condenses into fine droplets in the air forming clouds. When the droplets in the clouds get big enough, gravity pulls them to the Earth as precipitation, better known as rain, sleet, snow, hail, dew, or frost. 2/17/2019

The Carbon Cycle Carbon is often called the building block of life. Carbon is found in all organic substances—from fossil fuels to our own DNA. Carbon compounds can be solid, liquid, or gas under conditions commonly found on the earth's surface. Carbon atoms continually move through living organisms, the oceans, the atmosphere, and the crust of the planet. This movement, known as the carbon cycle, can take millions of years. 2/17/2019

The Carbon Cycle Carbon dioxide is cycled by green plants during photosynthesis to make food. Animals release carbon dioxide back into the air as a waste product from respiration. http://www.windows.ucar.edu/cgi-bin/tour_def/earth/Water/co2_cycle.html 2/17/2019

The Carbon Cycle Decomposers release CO2 gas into the air when they break down dead organic matter. The burning of fossil fuels, volcanoes and forest fires also send carbon dioxide back into the air. http://www.windows.ucar.edu/cgi-bin/tour_def/earth/Water/co2_cycle.html 2/17/2019

The Nitrogen Cycle Nitrogen is used by living organisms to produce organic molecules. Most nitrogen is found in the atmosphere where it exists as a gas. Other major sources of nitrogen are the soil and the oceans. On the surface of the Earth, nitrogen is mostly stored in living and dead organic matter. Nitrogen cycles from the atmosphere through plants and animals, into the soil, and then back into the atmosphere during the nitrogen cycle. 2/17/2019

The Nitrogen Cycle When you take a deep breath, most of what you inhale is nitrogen. Nitrogen makes up about 80% of our atmosphere. http://eo.ucar.edu/kids/green/images/nitrogencycle_sm.jpg 2/17/2019

The Nitrogen Cycle Our bodies need nitrogen, but cannot use the nitrogen that is inhaled. We get the nitrogen we need from the food we eat. http://eo.ucar.edu/kids/green/images/nitrogencycle_sm.jpg 2/17/2019

The Nitrogen Cycle Plants, which also need nitrogen to live, get theirs from the soil. Bacteria play a big part in transforming nitrogen so that it can be used by plants and animals. http://eo.ucar.edu/kids/green/images/nitrogencycle_sm.jpg 2/17/2019

The Nitrogen Cycle Nitrogen cycles from the atmosphere through plants and animals, into the soil, and then back into the atmosphere during the nitrogen cycle. http://eo.ucar.edu/kids/green/images/nitrogencycle_sm.jpg 2/17/2019