What is the Buffering Capacity of Freshwater?
Freshwater lakes and rivers act as buffers against acid rain, but even they have their limits. A buffer resists changes to pH. Lakes are buffered by the presence of dissolved carbonate and bicarbonate ions (from the weathering of rocks). Create a buffer solution to simulate a freshwater lake by adding one-half teaspoon of baking soda to one liter of distilled water. Pour 25 milliliters of buffer solution into a beaker and pour 25 milliliters of regular distilled water into a second beaker. Add six drops of Universal Indicator Solution to each beaker. Now add “acid rain” (see recipe above), to the beakers, drop by drop. The solutions will turn pink when they become acidic. Note how many drops it takes to turn each beaker pink (acidic). What is the Buffering Capacity of Soil? The buffering capacity of soils may be measured by placing two similar soil samples into filter paper and pouring distilled water over one and “acid rain” (see recipe above) over the other. Collect the filtered wate
