Eye color: The myth. One of the oldest myths in human genetics is that having blue eyes is determined by a single gene, with the allele for blue eyes recessive to the allele for non-blue eyes (green, brown, or hazel).Many people who know nothing else about genetics think that two blue-eyed parents cannot have a brown-eyed child.ye color: The myth. One of the oldest myths in human genetics is that having blue eyes is determined by a single gene, with the allele for blue eyes recessive to the allele for non-blue eyes (green, brown, or hazel).
Micrometer Caliper. a measuring instrument whose conversion mechanism consists of a screw-nut micropair. Micrometer calipers are used to measure linear dimensions by the absolute contact method.omplete turns are read from a scale marked on the hub of the micrometer caliper, and fractions of a turn are read from a circular scale marked on the drum. A displacement of the screw of not more than 25 mm is optimum because of the difficulty of manufacturing a screw with an accurate pitch over a greater length.
mÄ«Â·krÅmâ²Â·Ä­Â·tÉr), sometimes known as a micrometer screw gauge, is a device incorporating a calibrated screw widely used for precise measurement of components in mechanical engineering and machining as well as most mechanical trades, along with other metrological instruments such as dial, vernier, and digital calipers.hese permit measurements within 0.001 millimetre to be made on metric micrometers, or 0.0001 inches on inch-system micrometers. The additional digit of these micrometers is obtained by finding the line on the sleeve vernier scale which exactly coincides with one on the thimble.