Separating Sediments By Particle Size:
This week the climate class began separating their samples by filtering the sediment through a series of nested screens to isolate the sand, silt, and clay particles. Some of the samples were quite loose and were able to be screened dry, but most of the samples were extremely compact and required water screening.
The process for separating the wet sediments is similar to the dry, but the water is the mechanism moving the samples through the screens rather than motion. It is complicated to capture the silt and clay after screening, because if a pan is used at the bottom of the series of screens, the water has no place to escape. As a result the amount of silt and clay is the difference of the original sample weight and the remaining sediments.
Determining The Amount Of Organics In The Samples:
The class also began determining the amount of organic material present in each of the samples. This was done by weighing the samples, then heating them in a kiln for two hours at 200° Celsius, then subtracting the before and after weights.