The Earth Recycles Too! Earth system scientists understand that matter can not be created or destroyed within the Earth system. The Earth is considered a closed system. The Earth has cycled and recycled the same materials for billions of years. The materials that continuously recycle and circulate are minerals, elements, chemicals, nutrients and energy through the Earth’s system.

The Earth as a System Ask questions like: Can you think of a human body system? What is an example of a man made system? Can you think of a machine that acts like a system? Is there an example of a system within a system? Can you think of a system within a forest? A system is a group of interconnecting components that make up a whole. Processes are within all systems whether they be natural or man made. They can range in size from microscopic to immense. Many systems are interrelated, and cycles often operate inside larger systems.

How does the Earth System work? Earth system science(ESS) studies many interconnected processes called cycles. They cycle and recycle matter and energy around the Earth. Today we will get an overview of four cycles. As you may have learned by now, Earth System Science (ESS) looks at the earth as a single system where the 4 spheres work together and interact to circulate matter and energy and keep the Earth functioning at a level that sustains life in the biosphere. The Earth cycles and recycles both matter and energy around and has been doing it since the formation of the Earth around 4.54 billion years ago. To learn about ESS we must look more closely at these cycles that circulate both matter and energy around our home planet.

Cycles that Keep Energy and Matter Moving! The Water Cycle The Carbon Cycle The Rock Cycle The Nitrogen Cycle As you may have learned by now, Earth System Science (ESS) looks at the earth as a single system where the 4 spheres work together and interact to circulate matter and energy and keep the Earth functioning at a level that sustains life in the biosphere. The Earth cycles and recycles both matter and energy around and has been doing it since the formation of the Earth around 4.54 billion years ago. No new matter is created or destroyed, it is cycled around and may change form. There are more cycles but these are all we will cover in this lesson.

What Drives the Cycles of the Earth System? The Sun drives many of the cycles. The heat and activity of the Earth’s core drives the rock cycle. Gravity works with the Sun and the Earth’s core as a major force in the cycles. Circulating matter and energy around the Earth system will always need a driving force like the sun, gravity, or the heat of the Earth’s core.

In this Lesson…you will… Review the water cycle by adding information to a graphic organizer. Identify facts from the nitrogen cycle by completing a cloze paragraph. Learn about the rock cycle through watching a video. Summarize the carbon cycle by adding information to a graphic organizer.

The Water Cycle Use this slide to review the water cycle with the class. Invite students to come to the board to explain the cycle using the diagram.

The Carbon Cycle The red arrows indicate ways carbon is released into the atmosphere. The yellow arrows indicate ways carbon is stored away for long periods of time in vegetation, in the ocean, and as fossil fuels. Carbon is not created or destroyed but converted from one form to another by heat, plant and animal respiration, and decomposition from bacteria and fungus. The carbon cycle involves all four of the Earth spheres. Photosynthesis from plants takes CO2 from the atmosphere and converts it to O2. Carbon dioxide is a greenhouse gas and is important for maintaining a habitable surface temperature on Earth.

The Nitrogen Cycle Nitrogen is needed for all living things. Around 78% of the atmosphere is made of nitrogen gas, yet that nitrogen is not easily available to living things in the biosphere. Plants absorb nitrogen that is “fixed” in the ground by bacteria and available in the soil. Animals get nitrogen from eating plants and other animals that eat plants. When an animal or plant dies it decomposes in the ground where bacteria return the nitrogen to the soil. Plants need nitrogen to make carbon dioxide(CO2) into oxygen (O2) during photosynthesis. Nitrogen is part of all animal DNA and proteins.

The Rock Cycle You will notice some of the cycles happen quickly, within short periods of time we call these fast processes. Other cycles happen more slowly and will happen over hundreds, thousands, and millions of years – we call these slow processes. There are 3 types of rock shown above.

Cycles that Keep Energy and Matter Moving! The Water Cycle The Carbon Cycle The Rock Cycle The Nitrogen Cycle As you may have learned by now, Earth system science (ESS) looks at the earth as a single system where the 4 spheres work together and interact to circulate matter and energy and keep the Earth functioning at a level that sustains life in the biosphere. The Earth cycles and recycles both matter and energy around and has been doing it since the formation of the Earth around 4.54 billion years ago. There are more cycles but these are all we will cover in this lesson.

In what ways do cycles help the Earth system function? Why does the Earth’s system have cycles? To regulate temperature To clean the water To redistribute the water To create new land and to change rocks into other rocks To move carbon from one form to another keeping a CO2/O2 balance in the atmosphere Nitrogen moving from one place to another Energy moving from the sun-to plants-to animals and- into the soil

Essential Questions In what ways do cycles help the Earth system function? How does the water cycle redistribute water on Earth? How are humans part of the carbon cycle? Why is it essential for the Earth to recycle?

Sources Forest image: http://lh6.ggpht.com/0S0gP0THaCSI2i7WwnKoELVVQJxdK9QESTF7s_EqvfKQxUPu08ufPCthCeYAtPRTQi8cFojOqE3-KM9pEbOJQS-I42k=s0 Sun image: http://upload.wikimedia.org/wikipedia/commons/c/ce/Sun01.jpg Earth’s core image: http://discovermagazine.com/~/media/Images/Issues/2013/Jan- Feb/earths%20layers.jpg Apple image: http://upload.wikimedia.org/wikipedia/commons/b/b5/Navionics_Apple_ Team.png The Carbon Cycle: http://www.outgoingtides.net/wp- content/uploads/2012/08/C-cycle.jpg