What are the two ways energy can be transfered
Work or heat (through conduction, convection and radiation)
Define heat
heat is energy that is in the process of being transferred from one object to another as a result of a temperature difference between them
What is internal energy?
total energy contained in molecules of a substance
This includes:
Thermal energy (kinetic energy of molecules)
potential energy (attractive forces between the molecules)
What is Sensible Heat? + formula
when heat transfer results in a temperature change
(some things don’t cool/heat the same amount the same heat transfer)
Q = m c delta T
q = heat flow in joules
m = mass in kg
t = temp change in K
c = specific heat capacity
what is Latent Heat
when heat transfer results in a phase change
(ice to water to gas)
When is latent heat released vs absorbed?
What is the names for phase transitions?
During melting, evaporation, sublimation latent heat is absorbed
During freezing, condensation, deposition latent heat is released
Latent heat of ____:
Vaporization: liquid <–> gas
Fusion: solid <–> liquid
Sublimation: solid <–> gas
What is the adiabatic process?
Thermodynamic process in which temperature changes without heat transfer, due to pressure.
What is the Diabatic process?
Thermodynamic process in which temperature changes due to the transfer of heat
What are the different forms of heat transfer?
Conduction: heat transfer thru physical contact
Convection: heat transfer through a medium like air or water
Radiation: energy that travels as an electromagnetic wave, it doesn’t need a medium and can travel in a vacuum.
What are the two types of convection?
Thermal convection: Caused by density differences that result from temperature differences
Mechanical convection: caused by mechanical forces such as the wind
Does a hotter black body emit more or less radiation than a cooler black body
hotter emit more
Does a blackbody emit radiation at all wavelengths equally?
NO
What is plancks law used for?
determining the emission of radiation at any given wavelength
The wavelength at which the max radiation emission occurs is called the peak emission wavelength, does a hotter blackbody have a longer or shorter peak emission wave length
shorter
What does wiens law say
The wavelength of maximum emission is inversely proportional to the temperature
the hotter the substance the shorter the substance of peak emission
What is the stefan boltzmann law used for
used to calculate air and surface temperature
the formula is
E= blackbody constant, stephan boltzmann constant, T for temp in K to the power of 4
What does radiation do when it hits a surface?
the substance will exibit absorptivity (a), reflectivity (alpha) and transmissivity (t).
These all add up to 1/100% but typically radiation is 30% absorbed, 30% emitted and 40% transmitted
What is albedo?
it is the reflectivity of a surface.
For example clouds, snow, ice have high albedo, trees lower albedo
