Even with similar results, scientists may wait until an investigation has been repeated many times before accepting the results as correct. If more than one variable changes at the same time in an experiment, the outcome of the experiment may not be clearly attributable to any one of the variables. Organize information in simple tables and graphs and identify relationships they reveal. Read simple tables and graphs produced by others and describe in words what they show. Understand writing that incorporates circle charts, bar and line graphs, two-way data tables, diagrams, and symbols.
Many systems contain feedback mechanisms that serve to keep changes within specified limits.
Changes on the earth's surface happen very slowly over long periods of time. Describe and measure the process of radiometric dating using the concept of half-life. All students will have the opportunity to record data, make observations, and share in experimentation and discussion. In addition, the visual and numerical natures of the models allow for a wide range of reading levels. Finally, classes are heterogeneously mixed, all are expected to participate, and all will have access to this exciting technology.