Page 6 - Curriculum Visions Dynamic Book

(Below) Fibre diameters compared. KEY
Human hair 90 microns
Fibreglass 14 microns
Typical optical fibre 10 microns
Silk 5 microns
Thinnest glass microfibre 0.1 of a micron
Whether they are fibres or filaments, they are very long compared with their width. This shape is what distinguishes them from a sheet of the same material.
A human hair is about 90 microns across (a micron is short for micrometre, which is a millionth of a metre). You can use this to judge the thickness of all other fibres and filaments. Silk, for example, is about 5 microns across, while a glass fibre used for sending messages may be about 10 microns across. Wool fibres are usually 16 to 40 microns. By the time fibres reach 150 microns across, they are getting less flexible and are called bristles.
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