Metrology and Surveying PDF

Metrology and Surveying Week 1 – Week 2  What is Metrology Metrology comes from the Greek word “metron” and “logos” which literally means the study of measurement. This study covers both the experimental and theoretical aspects of measurement and the determination of th...

Metrology and Surveying Week 1 – Week 2  What is Metrology Metrology comes from the Greek word “metron” and “logos” which literally means the study of measurement. This study covers both the experimental and theoretical aspects of measurement and the determination of the levels of uncertainty of these aspects.  Origin of Measurement Early Human Societies The earliest forms of measurement were based on human body parts and natural objects. For example, the "cubit" was a unit of length based on the distance from the elbow to the tip of the middle finger. The "foot" was similarly based on the length of a human foot. Agriculture and Trade As agriculture and trade developed, there was a need for more standardized measurements. Early civilizations like the Egyptians, Sumerians, and Indus Valley people created more consistent systems for measuring land, volume, and weight. Origin of Measurement Origin of Measurement  Origin of Measurement Egyptians The Egyptians developed one of the first standardized systems of measurement, which included the cubit for length. They also used scales to measure weight, which was crucial for trade and the construction of their monumental architecture. Mesopotamians They contributed significantly to the development of units for measuring grain, land, and other commodities, which were essential for their complex economy. Babylonians They used a base-60 (sexagesimal) number system, which influenced the division of time (e.g., 60 minutes in an hour) and angles (360 degrees in a circle).  Origin of Measurement Greeks Greek philosophers and mathematicians, such as Pythagoras and Euclid, advanced the understanding of geometry and spatial measurement. They also worked on the standardization of weights and measures. Romans The Romans further standardized measurement systems across their empire, which included units like the "mile" (mille passus, or a thousand paces) and "pound" (libra).  Origin of Measurement Middle Ages: Measurement systems in medieval Europe varied widely but started to become more standardized as trade expanded. The creation of guilds and the rise of cities required more consistency. Scientific Revolution The 17th and 18th centuries saw a major transformation in measurement with the advent of scientific instruments and the development of the metric system in France. The metric system was designed to be a universal and rational system of measurement based on the decimal system. Standardization of Measurement Standardization of Measurement Significant Dates in US Metric History Fields of Metrology SI Units vs English Units (Origin) SI Units vs English Units Conversion  Sample Problem A carpenter needs to cut a piece of wood measuring 48 inches long. How long is the wood in centimeters?  Sample Problem A hiking trail is measured at 5,280 feet. How many meters is this?  Sample Problem A driver travels a distance of 60 miles. How far did they travel in kilometers?  Sample Problem A ribbon is 200 centimeters long. How long is the ribbon in inches?  Sample Problem A swimmer completes a 100-meter race. How many feet did the swimmer cover?  Sample Problem A cyclist rides 50 kilometers in a race. What is this distance in miles? The Steel Rule The Steel Rule (Overview) The Steel Rule (Measurement and Accuracy) The Steel Rule (Applications Features and Maintenance) The Steel Rule (Good Practices) Here is the correct way to measure a part with a steel rule. Notice that we are measuring from the 1" graduation on the left. (Be sure to subtract 1" from the measurement you read.) It is more accurate to measure between two graduation lines than from the end of the rule The Steel Rule (Good Practices) It is okay to measure from the end of the rule when there is a hard stop that you can press the rule against. The accuracy of this measurement depends on the quality of the grinding of the end of the rule The Steel Rule (Good Practices) Trying to align the end of the rule with the edge of a part is simply not an accurate way to measure The Steel Rule (Good Practices) When the rule is laid flat on the part, you cannot get an accurate measurement because of parallax The Steel Rule (Good Practices) If the steel rule is at an angle, the measurement cannot be accurate.  The Steel Rule (Good Practices) Another use for a rigid steel rule is to check the flatness of a part. With a good steel rule, you should be able to see 0.0005" of deviation from flat. The Vernier Caliper The Vernier Caliper The Vernier Caliper The Vernier Caliper (Modes of Measurement) The Vernier Caliper (Modes of Measurement) The Vernier Caliper (Proper Way to Hold)  The Vernier Caliper (Measurement) The main scale contributes the main number(s) and one decimal place to the reading (E.g. 2.1 cm, whereby 2 is the main number and 0.1 is the one decimal place number) The vernier scale contributes the second decimal place to the reading (E.g. 0.03 cm) The Vernier Caliper (Measurement) The Vernier Caliper (Measurement)