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Everything aboutTemperature.

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What is temperature?• Temperature is a physical property

of a system that underlines thecommon notions of hot and cold.

• Specifically, temperature is aproperty of matter.

• Temperature is a degree of hotnessor coldness that can be measuredusing a thermometer.

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• Temperature is one of the principal of

thermo.• On the microscopic scale, temperature isdefined as the average energy ofmicroscopic motions of a single particle inthe system per degree of freedom.

• On the macroscopic scale, temperatureof the unique physical property thatdetermines the direction of heat flowbetween two objects placed in thermalcontact.

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• It’s also measure of how fast the atoms andmolecules of a substance are moving.

• Temperature is measured in degrees on theFahrenheit, Celsius and Kelvin scales.

• A map of mean temperature• as a function of location.

• Water freezes at 0 oC.• the frost shown here is

• at -17 o

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• What is thermometer?

• A clinical mercury

thermometer.

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• A thermometer is an instrument that measuresthe temperature of a system in a quantitative

way.• The easiest way to do this is to find a substance

having a property that change in a regular waywith its temperature.

• The most direct 'regular' way is alinear one:t(x) = ax + b,where t is the temperature of the

substance and changes as theproperty x of the substance changes .

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The role of temperaturein nature.

• Temperature plays an important role in almost allfields of science, including physics, geology,chemistry, and biology.

• Many physical properties of materials including

the phase, density, solubility, vapor pressure, andelectrical conductivity depend on the temperature.• Temperature also plays an important role in

determining the rate and extent to which chemical

reactions occur.• This is one reason why the human body hasseveral elaborate mechanisms for maintaining thetemperature at 37 °C.

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Units of temperature.•

The basic unit of temperature(symbol: T ) in the InternationalSystem of Units (SI) is the Kelvin(Symbol: K).

• The Kelvin and Celsius scales are, byinternational agreement, defined bytwo points: absolute zero, and thetriple point of Vienna Standard MeanOcean Water (water speciallyprepared with a specified blend ofhydrogen and oxygen isotopes).

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• Absolute zero is defined as beingprecisely 0 K and −273.15 °C.

• Absolute zero is where all kineticmotion in the particles comprisingmatter ceases and they are at

complete rest in the “classic” sense. • At absolute zero, matter containsno thermal energy.

• Also, the triple point of water isdefined as being precisely 273.16 Kand 0.01 °C.

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Prepared byChortonova Begimay10 “A”