Physical Properties Of Hair Forensics

Life was long gone from the cold, bloody corpse when the criminal offence scene investigators arrived. The seasoned team soon confirmed the expiry was a murder, merely no footprints, no fingerprints, no weapons were found–a few strands of pilus caught in the dead adult female's broken fingernails were the only evidence the killer left behind.

Who's the culprit? Ask your students. Teaching bones physiological science concepts is interesting from a forensics betoken of view. By incorporating a problem-solving arroyo to science didactics, teachers appoint their students in exciting and innovative ways. Forensic labs too provide "existent-globe" applications of science and math.

Trichology is what?

Trichology is the scientific written report of the structure, office, and diseases of homo hair. Medical professionals, beauticians, and forensic scientists, among others, practise occupations within trichology. Hair is a valuable tool for forensic scientists. It is more than resistant to decay than most other torso tissues and fluids, thus remaining intact far longer than other evidence. This durability makes hair ane of the nigh frequently found pieces of evidence at crime scenes.

A hair shaft is composed of iii layers. The outer layer, orcuticle, consists of overlapping scales, with the free ends of the scales directed toward the tip of the shaft. Just beneath the cuticle is thecortex, made upwardly of meaty, elongated cells and often containing pigment granules. The key core of a pilus shaft is the medulla, equanimous largely of air spaces.

Forensic scientists perform 3 major types of pilus analysis: (1) testing the hair shaft for drugs or nutritional deficiencies in a person's system, (2) analyzing DNA collected from the root of the hair, and (3) viewing hair under a microscope to determine if information technology'due south from a detail person or animal. They usually report the pilus's calibration blueprint and appearance of the medulla to identify a hair of unknown origin.

Studying scale patterns

scientists study a cast of the hair shaft for determining scale pattern. The arrangement and shape of pilus scales can vary profoundly from species to species and are often very distinctive. Scientists usually allocate scales into one of 3 categories:

Coronal–Completely encircling the hair shaft
Barbed–Long, narrow, and not encircling the hair shaft
Imbricate–Short, wide, and non encircling the hair shaft

Plough your students into a CSI team and let them solve a "law-breaking" using hair assay. The forensic mystery will both engage and intrigue them while they learn scientific discipline concepts.

Making a bandage mount of a hair shaft

Materials

Latex or Smash Polish
2 Microscope Slides
Strands of Hair
Forceps
Microscope

Procedures

Identify a drop of latex near ane end of a clean slide.Notation:If you do non have latex, an alternate casting medium is nail smoothen. Brush a thin layer of smash smooth in the center of a make clean slide.
Tilt a second slide over the first (at approximately a 30° bending), ensuring that the slide ends farthest from the drib of latex are touching.
Slowly pull the tilted slide over the first until it touches the drib of latex.
Allow the latex to run forth the border of the tilted slide.
With a smooth movement, push the tilted slide back along the starting time slide to spread the latex into a sparse film.
Immediately place several strands of hair on the moving picture of latex or blast polish.
Allow the slide sit undisturbed for 10 to xv minutes allowing the latex to harden. If using boom shine, wait until the polish is tacky-dry out.
Once the latex is hard or polish is virtually dry, use forceps to pull every bit much hair every bit possible off the slide (it is not necessary to remove every strand of pilus).
Examine the slide using simply the low-ability objective of a microscope.Note:Practise not try to examine calibration casts nether the loftier-ability objective. Expect for impressions of individual scales and note the post-obit features:
- Whether or non individual scales completely surround the hair shaft
- The general shape of an private calibration
- Whether the exposed edge of a calibration is smooth or jagged

Studying the medulla

A whole mount allows study of the appearance of the medulla; still, a medulla is not always present in a hair. When medullae are present, they often show distinctive variations between species. The appearance of a medulla is classified every bit continuous (unbroken), intermittent (regular intervals), or fragmented (irregular intervals).

Making a whole mountain of hair

Materials

Microscope Slide
Mountant or H2o
Strands of Hair
Coverslip
Forceps
Microscope
Paper (for drawing)
Pencil (for drawing)

Procedure

Obtain a clean microscope slide and place a drop of mountant or water on it.
Place several strands of hair on the driblet of mountant or h2o.
Use forceps and slowly lower a coverslip onto the drop of mountant or water.
Examine the slide nether the low- and high-power objectives of a microscope. Examine several different sized hairs while noting whatever internal features such as granules or air spaces. Draw the hair showing the observed features.

Notation:If you are using a mountant, go on the finished slide flat until the mountant hardens. To harden the mountant, rut the slide in an oven at threescore° C for 1 twenty-four hour period or leave at room temperature for several days.

Identifying pilus

Identifying whether the hair is human or animal is the first stride in forensic pilus analysis. Homo hairs normally have a thin (less than â…" of the hair's diameter) or an absent medulla region. Animal hairs commonly have thick medullae (more than ½ of the hair's diameter). Compare the photos below to what you see nether the microscope.

The next pace is comparing the found hair to known suspects or animals present at the crime scene. This analysis can be subjective based on the person's experience at identifying the shape of the medulla. For commencement forensic students, simple identification of animal or human is sufficient. Using characteristics such as color, curliness, and thickness may assistance identify different human hairs.

The Hair Analysis Kit includes all supplies needed to make cast mounts and whole mounts of hair, including hair from animals and humans.

Extend your inquiry

Carolina offers many forensic kits that teach biology concepts in a fun, easily-on " existent-earth" scenario. Following are some kits you may want to consider.

Microscope Forensics Kit

Students undergo forensic "grooming," observing labeled slides of pilus, blood, and textiles–materials forensic investigators typically find at a crime scene. After studying the known slides, students receive a mock murder mystery and crime scene "show." They then examine the prove, compare it to the suspects' testimonies, and pinpoint the culprit.

The Case of the Murdered Mayor Kit

Students become crime scene investigators using their observational skills and deductive reasoning to solve this realistic crime scenario. Kit includes the following activities: dusting and lifting fingerprints, examining hair samples, analyzing impressions of tire tracks, blood typing with synthetic blood, examining entomological prove and reviewing a police interview log.

Carolina® Forensic Dissection Kit

Students acquit a pig dissection, modeling the protocols a pathologist uses for a human dissection. Upon completing the forensic dissection, students return the organs to the body cavity and suture the incisions. ACarolina'southward Perfect Solution® adult grunter heart and pig kidney are also included for comparison with the dissected specimen. Students utilise a fix of 7 prepared slides, extending and enhancing the dissection by examining tissue types found in each system.

Learn more than

Carolina 's extensive line of forensic science materials is platonic for teaching various concepts in science and math. These activities are too an engaging and innovative way to raise your science curriculum. For more information about our vast array of kits and supplies, phone call 800.227.1150 or visit www.carolina.com.