Soils are made of particles of different types and sizes. The space between particles is called pore space. Pore space determines the amount of water that a given volume of soil can hold. Porosity is nothing but the pores present in the spoil.
The porosity of a soil is expressed as a percentage of the total volume of the soil material. Porosity is an important measurement in areas where drinking water is provided by groundwater reserves.
Steps to find the porosity:
- Fill one measuring cup to 200 ml with sand, the second cup with 200 ml of clay and the third with 200 ml with small pebbles.
- Fill a graduated cylinder to 100 ml with water.
- Slowly and carefully pour the water into the first cup until the water just reaches the top of the sand.
- Pour slowly so no water spills out of the measuring cup. Record exactly how much water was used.
- Use the formula below to calculate the percent porosity for the sand:
Porosity = (Amount of water added to sample ÷ Total sample volume) x 100
- Repeat the same procedure with the clay and the pebbles.