BIOGRAPHY OF A RIVER

with breeding activities and egg and larval development of many organisms including amphibians andinsects.Termsconcentration: strength or density, as of a solution, as in amount of solute per volume of solutiondissolved oxygen (DO): oxygen gas (O ) dissolved in water2kinetic energy: the energy of a body resulting from its motionparts per million (ppm): a measurement of concentration of 1 unit of material dispersed in 1 million unitsof another (for water, same as mg/l)specific heat: the number of calories needed to raise the temperature of one gram of a givenosubstance 1 C, relative to the number of calories (one calorie) needed to raise the temperature of1 gram of water 1 o CADVANCE PREPARATIONRead carefully and practice the procedure for the DO kit ahead of time. Two can do it moreeasily than one. The manipulations take some practice.PROCEDUREI. Setting the stageA. The procedure can be done first without explanation, asking students to infer theproblems with thermal pollution. The teacher may wish to give the explanationsfirst.B. The method used for determining oxygen in water is one widely used in waterlaboratories. The greatest problem for accuracy is introduction of air bubbles inbottles during the procedure by agitation.C. In this experiment, agitation will be done deliberately as a way of demonstratingthe differences in oxygen holding capacities of water at different temperatures.3-92