Skill 1.3. Observation and Data Collection

To identify change in a grove of trees, we employ similar techniques as used in the observation of a tree limb. First, we measure the size of the trees at different time intervals. 

If the grove contains many trees, we may measure only a representative sample of trees and apply the results to make conjectures about the grove population. Finally, we closely monitor the trees for changes that may indicate disease or infection. 

To identify change in a stream, we measure and observe characteristics of both the stream itself and the organisms living in it. First, we measure the width and depth of the stream at different time intervals to monitor erosion. Second, we observe the water level at different time intervals to monitor the effect of weather patterns. Finally, using sampling techniques, we observe and measure the types and number of organisms present in the stream and how these characteristics change over time. 

One of the main goals of science is the study and explanation of natural phenomena. When studying natural phenomena, scientists describe the characteristic locations, sequences, and time intervals. Examples of natural phenomena studied by scientists include the locations of planets over time and the succession of species in an ecosystem. 

The eight planets of the solar system (Pluto was formerly included as a planet but has been removed as of Summer 2006) orbit the sun in a specific sequence. The time it takes to complete an orbit of the Sun is different for each planet. In addition, we can determine the location of each planet in relation to the Sun and to each other using mathematical models and charts. 

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