### Charles-Augustin de Coulomb

CoulombCharles CoulombCharles Augustin de Coulomb
Charles-Augustin de Coulomb (14 June 1736 – 23 August 1806) was a French military engineer and physicist. He is best known as the eponymous discoverer of what is now called Coulomb's law, the description of the electrostatic force of attraction and repulsion, though he also did important work on friction.

### Friction

coefficient of frictionstatic frictionfriction coefficient
Atomic-scale Friction Research and Education Synergy Hub (AFRESH) an Engineering Virtual Organization for the atomic-scale friction community to share, archive, link, and discuss data, knowledge and tools related to atomic-scale friction. Coefficients of friction of various material pairs in atmosphere and vacuum.

### Kilogram

kgmgmilligram
The kilogram (also kilogramme) is the base unit of mass in the metric system, formally the International System of Units (SI), having the unit symbol kg. It is a widely used measure in science, engineering, and commerce worldwide, and is often simply called a kilo in everyday speech.

### Wattmeter

electrodynamometerMirror bifilar electrodynamometerpower meter
The ammeter and voltmeter are both vulnerable to overheating — in case of an overload, their pointers will be driven off scale — but in the wattmeter, either or even both the current and potential circuits can overheat without the pointer approaching the end of the scale. This is because the position of the pointer depends on the power factor, voltage and current. Thus, a circuit with a low power factor will give a low reading on the wattmeter, even when both of its circuits are loaded to the maximum safety limit. Therefore, a wattmeter is rated not only in watts, but also in volts and amperes.

### Thermoelectric effect

thermoelectricPeltier effectSeebeck effect
At the atomic scale, an applied temperature gradient causes charge carriers in the material to diffuse from the hot side to the cold side. This effect can be used to generate electricity, measure temperature or change the temperature of objects. Because the direction of heating and cooling is determined by the polarity of the applied voltage, thermoelectric devices can be used as temperature controllers. The term "thermoelectric effect" encompasses three separately identified effects: the Seebeck effect, Peltier effect, and Thomson effect.

### Pressure measurement

manometerpressure gaugegauge pressure
Sphygmomanometer. 1) Simple manometer. 2) Micromanometer. 3) Differential manometer. 4) Inverted differential manometer. the left side of the face, used for measuring manifold vacuum, is calibrated in centimetres of mercury on its inner scale and inches of mercury on its outer scale. the right portion of the face is used to measure fuel pump pressure or turbo boost and is calibrated in fractions of 1 kgf/cm 2 on its inner scale and pounds per square inch on its outer scale. A: Receiver block. This joins the inlet pipe to the fixed end of the Bourdon tube (1) and secures the chassis plate (B). The two holes receive screws that secure the case. B: Chassis plate.

### Strain gauge

strain gaugesstrain gagestrain gages
A strain gauge is a device used to measure strain on an object. Invented by Edward E. Simmons and Arthur C. Ruge in 1938, the most common type of strain gauge consists of an insulating flexible backing which supports a metallic foil pattern. The gauge is attached to the object by a suitable adhesive, such as cyanoacrylate. As the object is deformed, the foil is deformed, causing its electrical resistance to change. This resistance change, usually measured using a Wheatstone bridge, is related to the strain by the quantity known as the Gauge factor.

### Heat

heat energythermalhot
Its behavior must be so regular that its empirical temperature is the same for all suitably calibrated and scaled thermometers, and then its hotness is said to lie on the one-dimensional hotness manifold. This is part of the reason why heat is defined following Carathéodory and Born, solely as occurring other than by work or transfer of matter; temperature is advisedly and deliberately not mentioned in this now widely accepted definition. This is also the reason that the zeroth law of thermodynamics is stated explicitly.

### Convection

convectiveconvection currentsconvection current
Atmospheric circulation is the large-scale movement of air, and is a means by which thermal energy is distributed on the surface of the Earth, together with the much slower (lagged) ocean circulation system. The large-scale structure of the atmospheric circulation varies from year to year, but the basic climatological structure remains fairly constant. Latitudinal circulation occurs because incident solar radiation per unit area is highest at the heat equator, and decreases as the latitude increases, reaching minima at the poles.

### Electric potential

electrical potentialelectrostatic potentialCoulomb potential
The quantity measured by a voltmeter is called electrochemical potential or fermi level, while the pure unadjusted electric potential V is sometimes called Galvani potential \phi. The terms "voltage" and "electric potential" are a bit ambiguous in that, in practice, they can refer to either of these in different contexts. * de:Elektrostatik#Potential und Spannung Absolute electrode potential. Electrochemical potential. Electrode potential.

### Temperature

temperaturesair temperaturewarm
Instrumental temperature record. ISO 1. ITS-90. Laser Schlieren Deflectometry. List of cities by temperature. Maxwell's demon. Orders of magnitude (temperature). Outside air temperature. Planck temperature. Rankine scale. Relativistic heat conduction. Satellite temperature measurements. Scale of temperature. Sea surface temperature. Stagnation temperature. Thermal radiation. Thermoception. Thermodynamic (absolute) temperature. Thermography. Thermometer. Virtual temperature. Wet-bulb globe temperature. Wet-bulb temperature. Adkins, C.J. (1968/1983). Equilibrium Thermodynamics, (1st edition 1968), third edition 1983, Cambridge University Press, Cambridge UK, ISBN: 0-521-25445-0.

### Atmospheric pressure

barometric pressureair pressurepressure
The measurement was based on an instrumental observation made from a reconnaissance aircraft. One atmosphere (101.325 kPa or 14.7 psi) is also the pressure caused by the weight of a column of fresh water of approximately 10.3 m (33.8 ft). Thus, a diver 10.3 m underwater experiences a pressure of about 2 atmospheres (1 atm of air plus 1 atm of water). Conversely, 10.3 m is the maximum height to which water can be raised using suction under standard atmospheric conditions. Low pressures such as natural gas lines are sometimes specified in inches of water, typically written as w.c. (water column) gauge or w.g. (inches water gauge).

### Electrical resistance and conductance

resistanceelectrical resistanceconductance
An instrument for measuring resistance is called an ohmmeter. Simple ohmmeters cannot measure low resistances accurately because the resistance of their measuring leads causes a voltage drop that interferes with the measurement, so more accurate devices use four-terminal sensing. Many electrical elements, such as diodes and batteries do not satisfy Ohm's law. These are called non-ohmic or non-linear, and their I–V curves are not straight lines through the origin. Resistance and conductance can still be defined for non-ohmic elements. However, unlike ohmic resistance, non-linear resistance is not constant but varies with the voltage or current through the device; i.e., its operating point.

### Magnetic field

magnetic fieldsmagneticmagnetic flux density
A magnetic field is a vector field that describes the magnetic influence of electric charges in relative motion and magnetized materials. The effects of magnetic fields are commonly seen in permanent magnets, which pull on magnetic materials (such as iron) and attract or repel other magnets. Magnetic fields surround and are created by magnetized material and by moving electric charges (electric currents) such as those used in electromagnets. They exert forces on nearby moving electrical charges and torques on nearby magnets. In addition, a magnetic field that varies with location exerts a force on magnetic materials. Both the strength and direction of a magnetic field vary with location.

### Gram

ggramsgr
The gram (alternative spelling: gramme; SI unit symbol: g; gramma, from Greek ) is a metric system unit of mass.

### Unit of measurement

unitunits of measurementweights and measures
A unit of measurement is a definite magnitude of a quantity, defined and adopted by convention or by law, that is used as a standard for measurement of the same kind of quantity. Any other quantity of that kind can be expressed as a multiple of the unit of measurement.

### Thermal expansion

coefficient of thermal expansionthermal expansion coefficientexpansion
Thermal expansion is the tendency of matter to change its shape, area, and volume in response to a change in temperature.

### Metre

metermmetres
The Measurement, Instrumentation, and Sensors Handbook. CRC Press. ISBN: 0-8493-8347-1.

### Accuracy and precision

accuracyprecisionaccurate
In industrial instrumentation, accuracy is the measurement tolerance, or transmission of the instrument and defines the limits of the errors made when the instrument is used in normal operating conditions. Ideally a measurement device is both accurate and precise, with measurements all close to and tightly clustered around the true value. The accuracy and precision of a measurement process is usually established by repeatedly measuring some traceable reference standard.

### Gibbs free energy

Gibbs energyfree energyfree-energy
During a reversible electrochemical reaction at constant temperature and pressure, the following equations involving the Gibbs free energy hold: and rearranging gives : which relates the cell potential resulting from the reaction to the equilibrium constant and reaction quotient for that reaction (Nernst equation), where Moreover, we also have: : which relates the equilibrium constant with Gibbs free energy.

### Body water

total body waterWaterfluid
The FA-MS instrument then measures the deuterium-to-hydrogen (D:H) ratio in the exhaled breath water vapour. The total body water is then accurately measured from the increase in breath deuterium content in relation to the volume of D 2 O ingested. Different substances can be used to measure different fluid compartments: Intracellular fluid may then be estimated by subtracting extracellular fluid from total body water. Another method of determining total body water percentage (TBW%) is via Bioelectrical Impedance Analysis (BIA). In the traditional BIA method, a person lies on a cot and spot electrodes are placed on the hands and bare feet.

### Concentration

concentrationsanalytical concentrationM
In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. Several types of mathematical description can be distinguished: mass concentration, molar concentration, number concentration, and volume concentration. A concentration can be any kind of chemical mixture, but most frequently solutes and solvents in solutions. The molar (amount) concentration has variants such as normal concentration and osmotic concentration.

### Engineering

engineerengineersengineered
Industrial scale manufacturing demanded new materials and new processes and by 1880 the need for large scale production of chemicals was such that a new industry was created, dedicated to the development and large scale manufacturing of chemicals in new industrial plants. The role of the chemical engineer was the design of these chemical plants and processes. Aeronautical engineering deals with aircraft design process design while aerospace engineering is a more modern term that expands the reach of the discipline by including spacecraft design.

### Photoelectric effect

photoelectricphotoelectronphotoemission
This phenomenon is commonly studied in electronic physics and in fields of chemistry such as quantum chemistry and electrochemistry. According to classical electromagnetic theory, the photoelectric effect can be attributed to the transfer of energy from the light to an electron. From this perspective, an alteration in the intensity of light induces changes in the kinetic energy of the electrons emitted from the metal. According to this theory, a sufficiently dim light is expected to show a time lag between the initial shining of its light and the subsequent emission of an electron. But the experimental results did not correlate with either of the two predictions made by classical theory.

### Electricity meter

electric meterelectric meterswatt-hour meter
Thomas Edison at first worked on a direct current (DC) electromechanical meter with a direct reading register, but instead developed an electrochemical metering system, which used an electrolytic cell to totalise current consumption. At periodic intervals the plates were removed and weighed, and the customer billed. The electrochemical meter was labor-intensive to read and not well received by customers. An early type of electrochemical meter used in the United Kingdom was the 'Reason' meter. This consisted of a vertically mounted glass structure with a mercury reservoir at the top of the meter.