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Forensic Science Activity I.D. #00028
Identify Yourself
Mad Scientist
Lab Girl
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Dirt Detective A
Lab Guy
Lab Rat
Super Sleuth
Corpse Specialist
Good looking Investigator
The Cool Detective
Suspect
Name: Date: Tick if forensic evidence is attached 1234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901212 1234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901212 1234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901212
A forensic geologist tries to discover how likely it is that two soil samples have come from the same source. They do this by identifying, analysing and comparing samples from the area under investigation (e.g. the crime scene) with samples recovered (e.g. from a suspect’s car tyre).
r o e t s Bo r e p ok u S
Soil composition can change vertically (as you go down) as well as horizontally (across the top) so it’s important to know where the samples being used for comparison are collected from.
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Teac he r
No two places on Earth have precisely the same type of soil. Samples taken from one area can be identified as being different from another, which means that soil found on a suspect’s shoes, clothes or other belongings can sometimes be used to link them to the scene of a crime.
Samples may be taken from a number of locations. The crime scene and the site used as an alibi may be sampled.
Check out the website below and see how forensic geologists have used soil to help convict murderers, burglars and even cactus rustlers!
After collection, soil samples are sent to a laboratory for analysis. After being dried (wet soil is a different colour to dry soil), the colour of the samples are compared. Those that don’t match can be easily eliminated. Minerals in the soil can give it a characteristic colour. Copper minerals appear green and minerals such as manganese and iron may make the soil look black.
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Ready-Ed Publications
A binocular microscope is then used for a closer look. Different rocks, minerals, pollen grains, leaf fragments, small animals and man-made objects such as glass, paint, asphalt and quantities of chemicals help make the sample soil unique.
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www.forensicgeology.net/ science.htm
Finding unusual things such as an uncommon mineral, a microfossil or a chemical can make finding a match faster.
o c . che e r o t r s super
The odour (smell) and texture (feel) of soils are also recorded. Sandy soils feel gritty with small separate grains, while clay is smooth and will leave a smear on the examiner’s skin. New methods, such as quantitative X-ray diffraction are being developed to help make soil analysis easier.
Related Outcome: Students analyse and compare soil samples.
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