Starting with the sand Mara adds water to the jar one tablespoon at a time. Water soaks the sample from the bottom up. She counts the number of tablespoons of water it takes to bring the water level up to the top of the sample. She repeats this process for the gravel and soil smaples. Mara adds 4 tablespoons of water to the sand, 7 tablespoons to the gravel, and 5 tablespoons to soil. calculate the porosity of each of Mara's sample using this formula and record the results in the chart. % porosity =(amount of water added to sample divide total sample volume)x100 "Total sample volume" is the amount of soil sand or gravel. A half cup is equal to 8 tablespoons. water added to sample % porosity sand 4 tablespoons gravel 7 tablespoons soil 5 tablespoons