Assignment Task:
It's time to save your soil and clean the glasses for the next experiment. Working over the sink, carefully pour the contents of one glass into a fine mesh strainer or a colander lined with a large paper coffee filter. Rinse the soil under running water, and then dump the damp soil into the small bucket with the soil from the earlier experiment. Repeat with the soil in the other glass.
Part:
You will now test the porosity (the space between the particles) of the soil. You'll compare the porosity of the soil with the porosity of sand and pebbles by measuring how much water fits in a glass with the same amount of each material. Note that the sand will be made up of a combination of fine and coarse sand particles. All of the pebbles, on the other hand, will be of roughly equal sizes.
Set three identical glasses on the counter or table. Put the half cup of sand in one glass, the half cup of pebbles in the second glass, and a half cup of your soil sample in the third glass.
Make a prediction about how much water can fit in each glass. Which sample will hold the most water? Write down your predictions on the porosity of all three samples.
Working with one sample at a time, add water to the glass one tablespoon at a time. Water should soak the sample from the bottom up. Count the number of tablespoons of water it takes brings the water level up to the top of the sample. Record the amount in the chart.
Calculate the porosity of each sample using this formula, and record the results in the chart. "Total sample volume" is the amount of soil, sand, or pebbles in the sample. A half cup is equal to 8 tablespoons. Need Assignment Help?
% porosity = (amount of water added to sample ÷ total sample volume) × 100