This lab report documents the microscopic and magnifying-glass examination of human (pulled and cut), animal, and synthetic fiber samples. The author compares observable hair structures — including the cortex, cuticle, pigment granules, and medulla — across species and sample types. Key findings include differences in medulla continuity between human and animal hair, the limited utility of the cuticle for individual identification, and the greater detail afforded by microscopy over a magnifying glass. The report also reflects on the forensic relevance of hair evidence and the surprising structural complexity revealed through close observation.
In all hair samples — including human pulled and cut samples from the head and body as well as the animal samples — it was fairly easy to identify the cortex, pigment granules, cuticles, and the medulla at the highest power of a rudimentary microscope. Using the magnifying glass was not nearly as effective; while the cortex and cuticle could be seen with greater clarity, the medulla and pigment granules were much more difficult to discern.
The medulla appears quite clearly as a darker area running through the middle of the human hair samples in a fairly solid line. In the animal hair sample, however, the medulla appears to be segmented — present in broken pieces rather than in the continuous solid line seen in the human samples. The cuticles could not be seen on the cut samples, but appeared largely similar in both the human and animal pulled samples. This contrasts with the cortexes of the two different species, which showed very different patterns from each other. The colors of the human and animal hairs were also quite different, although the pigment granules themselves appeared to have fairly similar shapes across both species.
Placing the hair and fiber samples on a flashlight did not produce many substantial differences in the observed color or shape of the strands. There did appear to be some difference in the color of the hair samples — they appeared lighter when placed on the flashlight — but this is easily explained as a direct result of the change in lighting. The outer parts of the hair strands, however, also appeared slightly more transparent, and the darker area of the medulla was more easily observable through the magnifying glass when the strands were placed on the flashlight than when they were observed against plain paper.
No clearly discernible differences were noted with the synthetic fiber sample when examined on the flashlight, however.
"Forensic relevance of cuticle presence or absence"
"Microscope reveals finer detail than magnifying glass"
"Hair's surprising structural complexity and experiment takeaways"
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