Soil – Innocent Until Proven Guilty

I have collected a soil from my school, but they’re is a plot twist… MR. CATER’S BIKE WAS STOLEN!!! Calm down, the police has recovered the bike and collected soil from the crime scene. I will be testing the soil I collected the crime scene to see if the match. Is the soil I collected innocent or guilty? Keeping reading to find out.

One day Mr. Cater put his bike against the wall while he was tying his shoe. When he he looked up the bike was gone. The police were able to recover his bike, but they found some soil from the crime scene. Our job is to see if the soil the police collected matches the soil I collected at Crockett High School in this investigation to determine the location.

Soil is important to forensic investigations, because it guides you to the location. Their are some soils that are native to certain locations.When discussing soil their are four major categories. Sand, Silt, Clay, and Loam. Sand, being the larger size of particles, feels gritty. Silt, being moderate in size, has a smooth or floury texture. Clay, being the smaller size of particles, feels sticky. Loam is relatively an even mixture of of sand, silt, and clay. You determine the soil texture by separating it. I finely pulverized the soil I collected, filled the jar I had with one quarter of the soil I collected, filled the jar with three quarters of water. I I then added a drop of non-foamy dishwasher detergent and shake the jar 15 minutes. Let it sit for a few days. I saw the layers of the sand, silt, and clay, and measured the thickness of each layer.  Last I used the soil texture triangle to determine the soil texture class.

For the soil I collected the thickness of sand deposit thickness: 1.7 centimeters, silt deposit thickness: 0.2 centimeters, the clay thickness: 0 centimeters. We found the percentages, and the soil texture I collected was Loamy Sand. The crime scene sand thickness: 10 millimeters, crime scene silt thickness: 10 millimeters, crime scene clay thickness: 2 millimeters. We found the percentages and the soil texture from the crime scene was Silt.

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Red Circle: The soil I collected, Black Circle: The crime scene soil the police collected

I did a pH chemical test on the soils. A soil pH measures acidity or alkalinity. The samples chemically don’t match. Although the soils are in the same range of acidity.

The soil I collected unfortunately don’t match to the crime scene soil. The soil is innocent! I learned that soil and pollen analysis are similar, because they both can narrow down a location of a crime scene. Since the soils don’t match the next step in this investigation is to close this case.

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One thought on “Soil – Innocent Until Proven Guilty

  1. Calisto, your report shows good understanding of the ways that soil can be used in a forensic investigation. I like all of the details you included when explaining how to determine soil texture. You showed your pH test results, but didn’t say which pH number the colors correspond to. You also could included the percentages of sand, silt, and clay as they were determined through your experiment. Overall this is a strong paper that could use some finishing touches.

    Like

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