# Relationship between soil porosity and permeability lab

### Porosity and Permeability Lab - PDF

Students test the porosity and permeability of sand, gravel, and clay. Objectives: clay or very fine soil Assemble the rest of the lab equipment and divide equipment for each . Arlington, VA: National Science Teachers Association,. In this lab, we will test the permeability and porosity of sand, gravel, and soil. . What do you think causes the difference in time that it takes water to pass. 5. Which type of soil do you think plants would most successful at obtaining water in? 6. Permeability is also related to Porosity. What is the relationship?.

Fill the same cup with sand up to the mark you drew. Pour the ml of water slowly into the sand. Stop when the water level just reaches the top of the sand. Record the amount of water left in the graduated cylinder in the right column. Calculate the pore space by subtracting the amount left in the graduated cylinder from the original mL. Repeat steps with the pea gravel and yard soil. Place the same amount of sand in the cup with a hole in the bottom. Get a timer ready.

## Porosity and Permeability Lab

Hold the cup over a beaker to catch the water. Pour the entire ml of water quickly into the cup of sand. Start recording as soon as the water hits the sand.

Stop timing as soon as the first drop of water comes out of the hole in the bottom. Record how many seconds it takes for the water to reach the bottom. Repeat steps with the pea gravel and soil. This water is frequently pumped up using water wells and used for humans and livestock. Groundwater from Texas aquifers is used for irrigation, city use, manufacturing, and livestock production.

Pumping water from many aquifers in Texas has resulted in a significant lowering of the water table. The water table is the upper surface of ground water below which the soil or rocks are permanently saturated with water and where the pressure of water in the soil equals the pressure of the atmosphere.

## LAB: Soil Porosity and Permeability

The water table fluctuates with the seasons and from one year to another based on how much precipitation has fallen, how much has been pumped out for human use and how much is used by plants and animals. Using a blue marker, trace the solid and dotted line labeled water table in the diagram below.

Less permeable rock below an aquifer that keeps groundwater from draining away is called a confining layer color the confining layer with a yellow pencil. The water held within the pores of the sand, soil, and clay above the confining layer is called an aquifer color the upper aquifer with a light blue pencil. Sometimes, deeper in the ground is an impermeable layer color the impermeable layer with a dark brown pencil.

When water is trapped between the confining layer and the impermeable layer, it forms an artesian aquifer color the lower aquifer with a dark blue pencil. How does soil type affect the movement of groundwater? Groundwater is water that moves through soil and rocks below Earth's surface. When groundwater moves through soil, the structure of the soil affects its movement. Groundwater moves through the spaces between soil particles.

These spaces are called pores. Not all soils have the same amount of pore space. The amount of pore space, or porosity depends on the number and size of pores in soil. If the pores in soil are all connected, allowing water to pass through them.

This means that soil is permeable.

The ease with which water moves through the soil is called permeability. Explain porosity and permeability in your own words. Porosity — Permeability - A soil with high porosity and many small pores can hold a lot of water, but it takes longer for the water to enter all the pores. This means that when a soil has higher porosity it has lower permeability.

### Porosity and Permeability Lab | Inam Ali - dayline.info

Record all data in the data table and be sure to answer all questions. Describe the appearance and texture of each soil type: The sample that had the highest drainage rate and retained the least amount of water was the most permeable.

Which sample does this describe? Why can some soil samples hold more water than others? Why are pore spaces in soil important to plants and organisms that live there?

### Porosity and Permeability Lab

Compare the permeability of these samples with their porosity. The sample that retained the most amount of water had the highest porosity. Was the most permeable sample the most porous as well? Which of these samples would you want to use for planting purposes?