Temperature: Is that property of a system which equals that of another system

when the two system are in thermal equilibrium.OrIs the physical property of a system which underlies the

common notions of”hot” and “cold”; the material with the higher temperature is

said to be hotter.

Temperature profile of the vertical structure of

the Atmosphere.

Pres

sure

var

iation

with

the

Altitud

e

Temperature Scales:

T (Kelvin scale) average K.E.Temperature is a measure of the

average kinetic energy of the particles in a system

What is ?

Thermal Expansion: LL0T T=Tf-T0

L=L0TConst.=Coefficient of linear expansion ()

L=Const.L0T

= L /L0T (1/0C) Is the increase in each unit length per each unit temperature

change.

The ball will not pass throughThe ring until the ring is hotter

Than the ball.

Different metal expand at different rates when heated.

Lakes freeze from the topThe comfort zoneLiquid Expansion:

Air cools faster than the

water does. The ice is less

dense than liquid water

Gas Expansion:VT (fixed P) V1/P (fixed

T)PV=const.T

Ideal gas law

The First law of thermodynamics:Conservation of Energy

Two means to increase the temperature: heat and work done

Internal Energy:The sum of the kinetic energies and potential energies of all the atoms and molecules in a

substance.USince TKE:

Temperature is directly proportional to UHeat: The form of energy that is transferred between two

substance because of their temperature difference.Q (it is not property of a system

like U) 1Cal=4.18J

Two objects with the same temperature do not Always feel as hold or as cold as one another.

Specific Heat Capacity:The amount of heat required to increase the unit mass of a certain substance by

unit temperature.Qm (fixed T)QT (fixed m) Q=Const.mTDepends on the kind of the

materialQ=mcT

C=Q/mT (j/kg0C)A 50 g sample of copper is at 250C. If 1,200J of energy is

added to the copper By heat, what is the final temperature?Imagine you have 1Kg each of iron, glass, and water, and that all of the samples are at 100C.Rank the samples from lowest to highest temperature after 100J is added to each

by heat.

Calorie: the energy necessary to raise the temperature of 1gm of Water from 14.50C to 15.50C.

U=Q + work1St law of thermodynamicsA thermodynamic system undergoes a process in which its internal energydecreases by 500J. If at the same time220J of work is done on the system.

Find the energy transferred to or from it by heat? W<0 W>0

W<0 W>0

An object of mass 6.5kg falls through a height of 50.0m and, by means of a mechanical linkage, rotate a paddle wheel that stirs 520g of water. The Water is initially at 150C. What is the maximum possible temperature rise?Heat Transfer:Conduction Convection Radiation

Net transfer of energy due to vibrational motions of atoms, molecules without a net Flow of the material.

Heat transfer by macroscopic movement of matter

Electromagnetic Radiation

Phase transition:

Relative humidity=(humidity/saturation density)100%Relative Humidity:

Humidity:The density of water vapor in the air

=(Actual vapor density/saturation vapor density)100%

Eva

pora

tion p

roce

ss is a co

olin

g p

roce

ss

High KE Molecules

Temp. decreases

What is the relative humiditywhen the humidity is

0.009kg/m3 and the temperature is 200C? Saturation density is

0.0173kg/m3 at 200CThe Second law of thermodynamics:

Hot ColddQPreferred direction to the “arrow of time”Heat engine is a device for converting heat into useful work

Heat

en

gin

e

Heat movers

Efficiency=(energy or work output/energy or work input)100%Efficiency=(work/

Qh)100%Heat engine

Maximum EfficiencyCarnot efficiency=(Th-TL/Th)100%Temperature must be in Kelvin

No device can be built that will repeatedly extract heat from a source and deliver mechanical work or energy without

ejecting some heat to a lower-temperature reservoir.

Entropy: is a measure of the amount of disorder in a system

Thank You

No more fluid