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Teaching about Earth's connected systems.

Our planet works as a set of interconnected systems involving water, rock, air and life. These systems are the hydrosphere, geosphere, atmosphere and biosphere, respectively. The energy that drives these systems comes from the Sun and from the Earth's inner heat. When something happens in one system, it can affect the workings of other systems. For example, displacement of rock layers on the ocean floor due to an earthquake (geosphere) can produce a tsunami (hydrosphere) that can destroy life (biosphere) if the tsunami reaches land. In drought conditions, much-needed rain (atmosphere and hydrosphere) can re-hydrate the land (geosphere) and re-start plant growth (biosphere).

It is important for children to understand the connectedness of Earth's systems, because human actions frequently have both positive and negative effects on the Earth system. For example, conservation practices can ensure that there are supplies of natural resources for future generations. On the other hand, careless waste disposal can result in soil, air and water pollution. Children need to learn how their lifestyle decisions can affect the health of the Earth system overall.

It can be difficult for upper primary and intermediate students to understand how Earth's systems operate. The very concept of "systems" might be new to them. One way to get them thinking in systems language is to ask them to name examples of everyday systems (transportation, school, computer, cell phone, digestive, solar, banking, healthcare, etc.)

Make a list of their suggestions on a board or flip chart. When you have a number of suggestions, ask the students to look these over and see what they all have in common. In other words, what makes these systems? You are looking for such responses as: they all have parts; their parts are connected; they need energy to operate; they all have a purpose; what happens in one part of the system can affect the other parts, etc. Guide the students to the understanding that a system is composed of parts that work together (processes) to accomplish a purpose. A system needs energy to operate.

Now, divide your students into groups of three or four, working at tables. Give each group an everyday object that operates as a system. These can include: umbrella, stapler, nail clipper, electric pencil sharpener, pair of safety scissors, electric torch, ballpoint pen, egg timer and other similar objects. Each group should also have a large sheet of poster paper and a set of coloured markers. Ask each group to draw a large picture of its object. They should then label the parts of their "systems" and draw arrows to show how energy flows through each system to make it work. The beginnings of their systems should be labelled 'Input' and the product resulting from the systems should be labeled 'Output'. Students should also identify the purpose of the system on each poster. When all groups are finished, post the drawings up in a gallery format and ask each group of students to explain how their object fits the criteria of a system. Each group should also describe the input, processes and output for its system.

In your next class session, you can emphasize the workings of a system by using your students themselves to model a system. Ask students to stand and join hands to form a circle. Identify one student as the Input and the adjacent student as the Output. Give the Input a whistle in one hand and the Output an electric torch. The Input and Output should not be holding hands with each other. When the Input blows the whistle, he or she should squeeze the next-door student's hand. The hand squeezes should travel around the circle until they reach the Output. At that point, the Output turns on the torch. Ask the students to explain how the system works: what are the parts, the processes, the Input, the Output and the energy flow? Ask how they could break the system and what it would take to repair it.

When you are confident that your students are beginning to feel comfortable with systems language and concepts, let them put their new knowledge to work. In another class session on a good weather day, put students into small groups and ask them to make sure they have pads and pencils. Take them outdoors and ask them to make and record observations about the air, water, land and life around them. Spend about 10-15 minutes doing this.

When students have completed their lists of observations, go back indoors. Give each group a sheet of poster paper and markers. Ask them to make a diagram showing how their observations fit into one or more parts of the Earth system. They might find it useful to group their observations into Water, Rock, Air and Life. Older students might prefer using Hydrosphere, Geosphere, Atmosphere and Biosphere. Students can use arrows or other symbols to illustrate connections between these Earth systems. For example, a student might draw an arrow from a pond to a cloud and label that arrow "evaporation". Other students might point out that the soil of the geosphere provides a home for animals and a medium in which plants grow. Take digital photographs of the posters so that students have a record of their thinking about Earth's systems.

Throughout your study of the Earth's environments, return to the concept of the Earth as a set of connected systems. This will help your students to understand the possible effects of their lifestyle decisions and will engender a sense of planetary stewardship.

More information Earth Science Week; Earth system interactions:

Ann E. Benbow PhD Director of Education and Outreach, American Geosciences Institute
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Title Annotation:Earth Sciences
Author:Benbow, Ann E.
Publication:Environmental Education
Geographic Code:4EUUK
Date:Mar 22, 2014
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