Lake Layers: Stratification.

This teacher guide and student workbook set contains two learning activities, designed for fifth through ninth grade students, that concentrate on lake stratification and water quality. In the activities students model the seasonal temperature changes that occur in temperate lakes and observe the resulting stratification of lake waters. Students then relate stratification to water quality within the lake. As prerequisites for these activities, it is recommended that students be able to record data in chart form and prepare graphs of temperature versus depth. In addition, they should be able to use a scale to weigh a flask of water, to read thermometers, and to measure with rulers; they should also be somewhat familiar with perimeter and area. The teacher's guide includes additional information to aid in processing the activities. Extension activities are provided along with suggested references, review questions and student worksheets. (MCO)