Lab 3: Discovering Local Data
Part D: Thinking About Data
Once data is available in graphic form, aspects of Earth's complex system can start to become more obvious; patterns and relationships that may be difficult to notice without the graphs will start to emerge. For example, one might have guessed that soil moisture was greater in months when more rain occurred, which are the warmer months for Greenville. Having the data makes it clear that soil moisture is actually greater in the cold months.
In Greenville, the natural vegetation is less active or dormant in the winter. Deciduous trees lose their leaves. The ground freezes and can become covered with snow or ice. There is less solar energy. In the warmer months, there are three natural changes that can reduce soil moisture. Increased solar energy thaws the soil and at some point causes evaporation. Trees and other vegetation become active, draw water out of the soil, and release it into the air. This is called transpiration. Finally, wind can increase both evaporation and transpiration.
As you learned in Lab 2, studying reservoirs and fluxes helps us understand the Earth as a system. Remember that reservoirs are places where energy, water, and elements are stored and fluxes are the movement of matter from one reservoir to another. Here is a simple example. There is a fixed amount of water on Earth. That water is divided up into smaller parts, called reservoirs. Earth's largest reservoir of water is in the ocean. Other reservoirs include the water that is frozen in ice caps and glaciers, the water that is in the ground, and atmospheric water, called water vapor. Flux (or flow) refers to the movement of matter or energy from one reservoir into another. In the work you just completed you saw that, at least in Greenville, PA, the reservoir of water in the soil became smaller as spring advanced towards summer, and the reverse happened as fall advanced towards winter.
Stop and Think
1: Which reservoir in Greenville, PA do you think gained water in the summer? In other words, to which reservoir did the soil moisture flow?
2: What other relationships among study site system components do you think might be worth investigating, and what data would you need? Suggest only relationships that you think data could be obtained for. Think about all the interrelationships that you and other students may have listed and diagrammed.