Thermodynamics

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27 Οκτ 2013 (πριν από 3 χρόνια και 10 μήνες)

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NS 3310


Physical
Science Studies

Chapter 4


Heat and
Temperature

Key Questions


What is heat? What is thermal energy? What is
temperature? Is there a difference?



How does heat move around?



Why do some things feel hot and others cold?



How do substances change their state of matter? How is
heat involved?



What are the laws of thermodynamics?



What is entropy?

Kinetic Energy of Molecules


Solids



Fluids



Liquids



Gases



Plasmas

Temperature


Temperature measures the kinetic energy
of molecules (this is external energy)



Fahrenheit



Celsius



Kelvin (absolute zero)

Thermal Energy


Thermal energy is the internal energy of a
molecule



Heat is a measure of the internal energy
that has been absorbed or transferred
from one body to another



Heat is measured in calories (c) or British
Thermal Units (BTUs)

Specific Heat and Latent Heat


Specific heat changes the temperature of an
object



Latent heat changes the phase of the material







For example: Ice to Water to Steam

Phase Transitions


Latent Heat of Fusion / Melting



Latent Heat of


Vaporization /


Condensation



Relative Humidity

Heat Flow


Radiation



Conduction



Convection

Thermodynamics


The First Law of Thermodynamics


Applied Law of Energy Conservation


W = J(Q
H



Q
L
)



The Second Law of


Thermodynamics


Heat always flows from an area


of higher concentration to an


area of lower concentration



Entropy

Perpetual Motion Machine?


Perpetual Motion Machines



Free Energy



Other Scams

Why Should We Worry About
Pseudoscience?

Key Concepts


Thermal energy is the internal and external energy of
atoms.


Heat is the transfer of thermal of energy between atoms.


Temperature is a measurement of the kinetic energy of
molecules.


Adding heat energy to substances makes their
temperature rise (specific heat).


To change the state of a substance requires even more
heat (latent heat).


Heat can be transferred by radiation, conduction and
convection.


Entropy describes the total energy of a system and tells
us that we cannot get more energy out of a system than
we put into it.