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Air in Soil
Task with Student Directions
Grade 5-8 Performance Task
Contributed by: New York State Education Department (NYSED)
NYS Alternative Assessment in Science Project (1996)

Task:

At this station, you will determine the amount of air space present in a soil sample.

Materials:

  • 2 metric cups (at least 250 ml)
  • water
  • paper towels
  • spoon
  • dry top soil sample
  • washing bottle
  • waste container

Background:

Soils in the natural environment are a mixture of mineral particles, plant remains, air, water, and other materials. Because mineral grains and organic materials are not always regularly shaped, the particles in soil have spaces between them. These air spaces may fill with air and/or water.

Directions:

  1. Pour 100 ml of water into one of the metric cups.
  2. Place 100 ml of soil into the other metric cup.
  3. Carefully pour the water into the cup containing the soil, observing closely as you do so.
  4. Stir gently until bubbles stop coming from the soil.
  5. Measure and record the volume of the water and soil mixture and complete the calculations on the data table.
 
Volume
Volume of Water
100 ml
Volume of Dry Soil
100 ml
Total volume of Water and Soil

200 ml

Actual Volume of Water and Soil mixture
ml
Difference Between Actual and Total
ml

 

6. Calculate the percentage of pore space filled with air in your soil sample. Show your work in the space below.

Percent (%) =

difference between total mixture volume

________________________________ X 100

actual volume of the soil

 

 

 

 

Answer ____________________

 

7. Based on your observations in this task, why might soil with a lot of air or pore space in it be better for plant growth than soil with little pore space? Use complete sentences in your explanation.








8. In the space below, design a controlled experiment you could use to determine the amount of water in soil sample taken from your backyard.














9. Empty the soil and water mixture into the waste container and rinse the metric soil cup.

 

 


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