Forensic Geology Lab: Digging Through the Sands of Crime

By aroth on Mar 09, 2016

As you know fossils are clues that allow us to see all the changes that happened throughout earth’s history, such as climate, weather, foods, etc. Index fossils are clues for a specific era of time, such as the Pre-Cambrian period. In this lab there is a strange twist worthy of the great Sherlock Holmes (well, assuming you know who he is). Apparently ________, a geology professor from Purdue University, was found with a shell in her lab coat, during a random search for empty Skittle bags. (Those administrators have nothing better to do than be on candy patrol). What is odd is that the particular mollusk found in her pocket is an index fossil, and the species is from an archeological dig site that is off limits to the public, ever since a strange metallic fin was found buried one foot below the surface. No evidence is allowed to be removed from this site.
 
_________ (AKA “Queen of the participle”) has accused four of her fellow professors of professional jealousy, stating that they have acted in an unprofessional manner, but re-arranging evidence. Each colleague has stated under oath that they were digging on the same day, but at different geologic depths, were seen by each other, emptied their pockets before they left, and could not have done what _________ has said.
 
Here is was the detectives have discovered. For purposes of this lab, one centimeter each in depth equals three million years:
  1. Professor ________________ was digging at a depth of 4 centimeters.
  2. Assistant Professor Braille Dot______ was digging at a depth of 8 centimeters.
  3. Dr. I.M.______________ was digging at a depth of 12 centimeters.
  4. Professor Emeritus ________was working at a depth of 14 centimeters.
NOTE: It was not determined as yet where _________ was excavating.
 

Preparation:

  1. Create a cardboard that has each actual shell (“fossil) labeled in Braille and Large Print. Label the shell by its Genus-Species name. Explain that the shell number indicates its depth in the sand by its age. State that these are index fossils, that is a specific fossil that is found worldwide at that depth.
  2. Purchase clean, playground sand, plastic tubs, various kinds of painting brushes and scoops.
  3. Have buckets nearby for students to place sand that has been scooped or brushed out.
  4. Have students place newspaper under the pans for easier cleanup.
  5. Caution students to brush and scoop slowly to avoid digging up a fossil at the wrong depth. When students come to the top of a fossil, use the brush.
  6. Make sure students measure accurately the depth of the fossil. This will come in handy as they review the data table.
  7. Fill in the blanks with the student’s favorite or non-favorite teachers or staff.
  8. Expect to take 4-5 days to complete the lab.

Materials

  • brushesillustration of fingerprints under a magnifying glass
  • scoops
  • sand
  • fossils
  • metric ruler
  • fossil board
  • pans
  • buckets
  • newspaper

Procedure

  1. Using the brush, sweep away and remove the first layer of sand until you find the first fossil.
  2. Measure the depth of the fossil.
  3. Carefully remove the fossil with a scoop, set it aside, catalogue it with your fossil board and continue digging until you reach the bottom of the pan.

Data Table 1: Down to the bottom

Depth (cm) Fossil

Key to Index of Fossils

  • 2
  • 4
  • 6
  • 8
  • 10
  • 12
  • 14

Fossil Time Period

  1.  
  2.  
  3.  
  4.  
  5.  
 
  1. Examine the fossil found in _________’s lab coat, and the other fossils found at the depths each professor was digging. One fossil was found at the wrong depth. This will be used to catch the professor who altered the site.
NOTE: Each centimeter in depth represents one million years of geologic time.

Data Table 2: Fossils found in the sands of crime

 

  Professor   Fossil

  1. 

 

  2.

 

  3.

 

  4.

 

  5.

    The professor who altered the dig site was: _________________  

Questions:

  1. How did you determine which geologist was guilty?
  2. What are index fossils?
  3. What are the characteristics of an index fossil?
  4. Why did you use a brush to uncover fossils?
  5. Why is geologic time helpful in determining the age of fossils?
  Bonus: Discuss why some organisms never appear in the fossil records.  

Variations

  1. Make the digging more difficult by adding rocks and fossils NOT on your fossil chart.
  2. Wet several of the different sand layers (and let it dry) for creation of a “real-life” fossil dig.
  3. Assign roles to each group member and job description: Head archeologist, Data Collection Specialist, Site Artist, Report Writer, etc. 

 

NGSS Standards:

Analyzing and Interpreting Data

  • Analyzing data in grades 9-12 builds on experiences from grades K-8 and leads to more detailed data analysis, using previous knowledge.
  • By applying previous knowledge built upon the Scientific Method, questions can be answered and new hypotheses developed to gather data and come to successful conclusions (HS-L54-3)

Constructing Explanations sand Designing Solutions

  • Constructing explanations and designing solutions in grades 9-12 builds on experiences from grades K-8 and leads to more detailed data analysis, using previous knowledge. Variables are eliminated as the experimental design continues 
  • Evaluation of evidence goes beyond the obvious and accepted explanations of solutions are altered (HS-L54-5)

Obtaining, Evaluating and Communicating Information

  • Obtaining, evaluating and communicating information in grades 9-12 builds on experiences from grades K-8 and leads to more detailed data analysis, using previous knowledge. The Scientific Method and all its steps are fully integrated in multiple formats; communication becomes essential in the experimental design in all its formats. To insure a product meets successful qualifications (HS-L54-1)
 
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