How to Calculate the Particle Angularity of Sand

Sedimentology is the branch of geology that examines characteristics of sedimentary deposits such as sand. Petrography is the branch of geology that examines mineral grains, which make up geologic deposits or earth materials like sand. The size and shape of sand grains in a natural sand unit or in a batch of earth materials has important implications for engineering, soil science and agronomy. Golf course designers and caretakers are particularly concerned with the sphericity versus angularity of sand particles used because angularity affects turf growth and playing characteristics of sand bunkers. Learn to calculate the angularity of sand particles easily.

Things You'll Need

  • Sand samples
  • Small zip bags
  • Binocular microscope
  • Needle probe
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Instructions

    • 1

      Obtain samples of sand from a variety of locations. Use small inverted zip bags to grab random samples of clean uniform sand from beaches, river banks, stockpiles, sand dunes, sand bunkers and sand traps on golf courses. Label each bag with location information.

    • 2

      Print out copies of the Krumbein scale charts given in the Resources section. Print several versions for your sand grain angularity analysis. The Kansas Geological Survey version is particularly useful because it rates angularity through sphericity on a scale of 1-9.

    • 3

      Place a small quantity of a sand sample on the illuminated stage of a low-power binocular microscope. View the sand grains through the various magnifications of the microscope. Use a needle probe to manipulate the sand grains and to center a small quantity in the center of the microscope frame.

    • 4

      Examine the edges and the general shapes and appearances of 100 sand grains from each sample. Compare the shape and outline of the 100 grains to those given on the Krumbein charts you printed out. Use the Kansas Geological Survey chart to assign number ratings to each of the 100 grains from each sample and then average these together for an average angularity versus sphericity number for the entire sample. Write the grain shape number obtained on each sample bag.

    • 5

      Arrange your analyzed samples in order from the most angular to the most spherical. Examine the texture and feel of sand grains from each sample between your fingers. Compare the samples and note any differences that you feel or observe.