Measuring Bulk Density

• 1). Select a hollow piece of pipe. Weigh the pipe, and calculate its interior volume. A cylinder's volume is equal to pi (roughly 3.14) multiplied by the square of the radius of the cylinder and the multiplied again by the cylinder height. For example, a 12-inch-long cylinder with a 3 inch radius would have a volume of: 3.14 x 9 x 12, or 339.12 cubic inches.
  
  
• 2). Set the pipe on top of the soil you want to measure, then hammer the pipe into the ground. This creates a core sample inside the pipe that has not been compacted, and thus has the same density as it did before sampling.
  
  
• 3). Dig out the ground around the pipe with a shovel until you reach the bottom of the pipe and can slide a flat piece of metal underneath it. Carefully lift the pipe full of soil out.
  
  
• 4). Dry the sample overnight in an oven set to 110 degrees Centigrade (230 degrees Fahrenheit). Standard soil density calculations use this oven-dry figure, which eliminates the weight of water in the soil as it boils off in the oven.
  
  
• 5). Weigh the full pipe, then subtract the weight of the empty pipe to get the weight of the soil in pounds. Divide this by the interior volume of the pipe to get the density of the soil in lbs. per cubic inch. For example, if the pipe used as an example earlier had 10 lbs. of soil in it, the density would be 10/339.12, or 0.0295 lbs. per cubic inch.
  
  

Calculating Clod Density

• 1). Dig out a sample of soil from the area you wish to calculate the density of and choose several cohesive chunks, or "clods."
  
  
• 2). Weigh each clod, then weigh a piece of paraffin wax before melting it onto the clod. This will protect it briefly from water, allowing its volume to be measured. Alternatively, wrap the clod in plastic wrap; weigh the piece of wrap you use.
  
  
• 3). Pour some water into a beaker with measurement lines on the side, then immerse the coated clod in the water. The water will be displaced to a higher mark on the wall of the beaker. The difference between the higher and the lower mark is equal to the volume of the clod.
  
  
• 4). Divide the clod's weight by its volume to get its density. For additional accuracy, do this several times with different clods, then average the results by adding them together and dividing by the number of samples.