Random Fiber Questions
What is the difference between yarn labeled S twist and Z twist?
S twist means the yarn is spun counterclockwise. Z twist means the yard is spun clockwise.
What is the other name for a compound microscope?
A light microscope
Which technique requires the sample to be ionized?
Mass Spectrometry
What is the most commonly used natural fiber?
Cotton (which makes cotton fibers have less value in terms of forensic evidence)
A weave pattern is determined by how many times the ____________ passes over the _______________
Weft / warp
Which microscope would you use to look at the cross section of a synthetic fiber to see its shape and measure its width?
Scanning Electron Microscope
What two techniques require the sample to be vaporized?
Gas Chromatography and Mass Spectrometry
What are synthetic polymer fibers made from?
Petroleum
What is the total number of weft threads and warp threads in a square inch of fabric called?
Thread count
What are the two types of microscopes used in fiber analysis that use light outside of the visible spectrum?
Ultraviolet and infrared microscopes
What tool have scientists recently started using to help them interpret spectroscopy data?
AI
What type of fiber is silk?
Natural Animal Fiber
What is the name of an instrument that measures the wavelength of light that a fiber absorbs, reflects, or transmits?
Spectrophotometer
What type of microscopy technique can you use to detect bodily fluids on a fiber?
What is the name of the technique that combines a microscope with a spectrophotometer?
Microspectrophotometry (MSP)
What are the three different types of animal fibers?
Hair, fur, silk
What part of the plant is cotton extracted from?
Fruit or seeds
What happens to the molecules of a fiber when infrared light is directed at them for infrared microscopy?
The bonds of the molecules absorb energy which causes them to vibrate, rotate, and stretch.
Briefly explain how molecules are separated from each other during gas chromatography.
The molecules travel down a tube or column at different rates depending on a property like their molecular weights or boiling points.
What chemical do they combine with cellulose to make different types of regenerated synthetic fibers?
Acetate