PROBLEM & WORD OF THE DAY POD: Would fibers be physical or
biological evidence?
WotD: Amorphous
VIDEO Video: Cold Case Files
Volume 1 “One Night on the Bayou”
EXIT TICKET & HOMEWORK Exit Ticket: Complete the 4 post video
questions
Homework: Complete questions for homework
PROBLEM & WORD OF THE DAY POD: How are fibers used in crime
scenes?
WotD: Crystalline
UNIT 4: FIBERSFiber evidence can be useful to identify or exclude suspects as
either physical or biological evidence.
UNIT OBJECTIVES Identify and describe common weave
patterns of textile samples Compare and contrast various types of
fibers through physical and chemical analysis
Describe principle characteristics used to identify common fibers
Apply forensic science techniques to analyze fibers
BOOK QUEST
EXIT TICKET & HOMEWORK Exit Ticket: How soon do fibers need to
be collected at a crime scene?
Homework: Go to
http://www.crime-scene-investigator.net/dont-forget-those-standards.html
For each of the evidence types identify the quantity and type of samples collected from a known source.
PROBLEM & WORD OF THE DAY POD: Why are fibers considered trace
evidence?
WotD: Direct transfer
BOOK QUEST CONTINUED
EXIT TICKET & HOMEWORK Exit Ticket: In the process of normal
activity we shed fibers and pick up fibers. Explain how these two facts can help determine what occurred at a crime scene.
Homework: Complete the Book quest through using Google for any questions that you were unable to complete.
PROBLEM & WORD OF THE DAY POD: How can fibers be used to solve a
murder case?
WotD: Fiber
JEFFREY MACDONALD’S CASE
Read the case and answer the question on the Jeffrey MacDonald’s case.
EXIT TICKET & HOMEWORK Exit Ticket: Journal Prompt for Article
Review
Homework: Find a case that used fibers and write a one paragraph summary.
PROBLEM & WORD OF THE DAY POD: List the 5 ways that fiber evidence
evaluation can be used to solve a case.
WotD: Mineral fiber
CASE SHARE OUT What case did you find?
Who was guilty?
What was the outcome of the case?
MICROSCOPE LAB Complete the second side of the
Hair/Fiber Microscope lab. Analyze the six fibers
EXIT TICKET & HOMEWORK Exit Ticket: What is the most common
form of fiber transfer to cause fiber evidence to be at a crime scene?
Homework: Journal Prompt #2 Lab Review. Complete for both parts of the lab, hair and fibers.
PROBLEM & WORD OF THE DAY POD: Two common lab techniques to
analyze fibers located at a crime scene are Microscopes and Infrared Spectroscopy. Describe the physical and chemical differences between these two techniques.
WotD: Monomer
ACTIVITY 4-1MICROSCOPE FIBER ANALYSIS Use the textbook to follow the lab
instructions Record the data on the data table
EXIT TICKET & HOMEWORK Exit Ticket: What percentage of fibers
are lost within the first 24 hours?
Homework: Complete the post lab questions and the lab journal prompt
PROBLEM & WORD OF THE DAY POD: There are three main destructive
fiber analysis; burning test, dissolving test, and dye test. What does it mean to be a destructive test?
WotD: Natural fiber
ACTIVITY 4-3 WEAVE PATTERN LAB Use the textbook to follow the lab
instructions Record the data on the data table
EXIT TICKET & HOMEWORK Exit Ticket: List 3 things that are
revealed by using a microscope for fiber analysis.
Homework: Complete the post lab questions and further research on fibers.
PROBLEM & WORD OF THE DAY POD: Describe the difference between
Warp and Weft. Do all fibers have both?
WotD: Polymer
ACTIVITY 4-4 TEXTILE IDENTIFICATION LAB Use the textbook to follow the lab
instructions Record the data on the data table
EXIT TICKET & HOMEWORK Exit Ticket: Hair made of proteins such
as wool, cashmere, mohair, angora, and silk, come from what type of fibers?
Homework: Complete the post lab questions.
PROBLEM & WORD OF THE DAY POD: List the three types of natural
fibers.
WotD: Secondary transfer
FIBER BURN TEST TIPS Use a sample large enough to determine if the fabric or
fiber will continue to burn or die out quickly. Hold the fiber or fabric with a forceps. Try to hold the
fabric parallel to the table so that the flames will move across the fabric or fiber. If you hold the fabric so that the fabric is suspended, the flames will engulf the entire fabric at once. This makes it difficult to determine if the fabric continues to burn after being held in the flame, or if the flames die out.
Hold the fabric in the flame for 3 seconds to ensure that the fabric is ignited.
To detect the odor of the smoke, it is important to check immediately after the fabric is ignited. You will most likely see a small amount of smoke that disappears quickly.
Note how the synthetic fabrics appear to melt and may look bubbly as they burn.
FIBER BURN LAB
FIBER BURN ANALYSIS KEY
EXIT TICKET & HOMEWORK Exit Ticket: Complete the Lab Journal
Prompt
Homework: Answer the Post lab questions.
PROBLEM & WORD OF THE DAY POD: What percentage of fibers are
produced synthetically? What does it mean for a fiber to be produced synthetically?
WotD: Synthetic fiber
FIBER DYE LAB Read the lab Place your fiber strips in each dye Return to your seats.
FIBER CLASSIFICATION Identify the following natural fibers as
Animal, Plant, or Mineral: Wool Fiberglass Hemp Cotton Silk Angora Asbestos Jute Cashmere Flax Alpaca
FIBER DYE LAB Pull Fabric strips out of the dye Rinse with cold water Pat dry with a paper towel Fill in the data table Compare the unknown samples to the
known colors Answer the post lab questions
EXIT TICKET & HOMEWORK Exit Ticket: List 2 advantages and 2
disadvantages of using Plant fibers.
Homework: Finish post lab questions and complete the journal prompt on lab
PROBLEM & WORD OF THE DAY POD: List the 2 types of Synthetic fibers
and give an example of each.
WotD: Textile
CRIME SCENES & BURNED FIBERS
EXIT TICKET & HOMEWORK Exit Ticket: Can a suspect truly destroy
or remove ALL evidence?
Homework: Complete the essay on crime scenes and burned fiber evidence.
PROBLEM & WORD OF THE DAY POD: Summarize the Unit in 6 points
WotD: Warp and Weft
SUMMARY Fibers are a form of class evidence. Fibers are a form of trace evidence. Fibers are spun into yarns having
specific characteristics. Yarns are woven, with different patterns,
into clothing or textiles. Fiber evidence is gathered using
different techniques.
SUMMARY Fibers are analyzed using burn tests,
tests for solubility in different solutions, polarized light microscopy, or infrared spectroscopy.
Fibers are classified as natural or synthetic.
Natural fiber sources include: Animal hair Plant seeds, fruit, stems, or leaves Minerals.
UNIT REVIEW Read Cases and complete the “think
critically”
Read the “Careers in Forensics” for Fibers and complete the Journal Prompt for Article Review.
Complete the end of Chapter Review
UNIT TEST & CASE STUDY Unit 4 Test: Fibers
Case Study: Read the case and summarize the case focusing on the types of evidence used to solve the case.
EXIT TICKET & HOMEWORK Exit Ticket: What careers use forensic
science?
Homework: Finish the review and study for the test. Folder for Units 3 & 4 are due tomorrow.