INTRODUCTION Around 6th century BC

INTRODUCTION
Around 6th century BC, the oldest caliper was found within a ship called the “Greek Giglio Wreck” near the Italian island Giglio, back then the caliper was made of wood.5 During the Han Dynasty (202 BC – 220 AD), the earliest calipers without a vernier scale originated in Ancient China and they were made out of bronze.4 It was not until a French Scientist named Pierre Vernier developed a secondary scale that provided an extra precision on the measurement scale. He is credited with the invention of the Vernier Caliper which was named after him.6 In 1631, Pierre Vernier published his journal entitled as “La construction, visage, et les proprietes fue quadrant nouveau de mathmatiques”, which paved the way for the introduction of the Vernier scale and through this scale, it enabled users to acquire precise measurements of objects at a greater level of accuracy.4
In addition to this, it was Jerome Lalande who popularized the name “Vernier” through his book “Traité d’astronomie”.4 In the present day, a vernier caliper is an instrument designed to gauge the dimensions and depth of the different objects, this tool is known to measure to a precision of one hundredth of a millimeter and one thousandth of an inch and it is also useful especially when it comes to measuring the diameter of circular objects such as cylinders because its jaws can be secured on both sides of the circumference.8
On the other hand, William Gascoigne invented the first micrometer caliper, also a measuring device, in the 17th century.1 In 1848, French inventor Jean Laurent Palmer was the one who first documented the development of handheld micrometer calipers because of him it was often called palmer screw.7 The micrometer caliper model that was developed by Palmer was then the foundation on which all the modern micrometer calipers were built. The micrometer caliper is also known as the micrometer screw gauge, it is an instrument which can measure the depth, thickness, and length of an object that fits between its spindle and anvil and is used for the precise measurement of small distances.3 The mechanism behind the modern micrometer caliper is based on the rotation of the screw that helps in achieving accuracy, its calibrated screw is used for precise measurements wherein it has a very high accuracy of 0.01 compared to the vernier caliper accuracy of 0.02.2
This paper aims to use the Vernier Caliper and Micrometer Caliper in the measurement of lengths; to accurately measure the dimensions of geometric objects by means of the Vernier and micrometer calipers; to determine the density of some solids by direct measurement of mass and volume and to compare the measured densities of some solids with listed standard densities from references.