Physics: Thermal Energy
entropy
the amount of disorder in a system
usually increases
the disorder in a system left to itself (no work done) will a. usually increase b. can decrease c. always remains the same
absolute zero
the lowest possible temperature on the Kelvin scale where all molecules would stop
thermodynamics
the study of the flow of heat energy
1st law of thermodynamics
this states that energy is never created nor destroyed:heat lost by an object is gained by another
2nd law of thermodynamics
this states that heat will always flow from hot objects to cold objects, efficiency is always less than 100%, and total disorder can never decrease
3rd law of thermodynamics
this states that it is impossible to achieve a temperature of absolute zero
temperature
two objects in thermal equilibrium have the same
temperature difference
what causes heat to flow?
aluminum because it is a better conductor, they are the same temperature
when a piece of aluminum and a piece of wood are at room temperature, which feels colder?
internal energy and temperature
when mechanical work is done on a system, there can be an increase in its a. internal energy b. temperature c. internal energy and temperature d. none
aluminum
which of the following is the best conductor of heat? a. wood b. water c. aluminum d. plastic
the ocean
Which of the following things has the most thermal energy? a. the ocean b. a camp fire c. a hot oven d. a hot water bottle
thermometer
a capillary tube with a liquid that is calibrated to measure temperature
refrigerator
a device that uses work to move heat from a cold place to a hotter one
radiation
a transfer of heat energy through space by means of electromagnetic waves
celsius
a unit of measurement that was once called Centigrade because there are 100 degrees between the freezing point of water in this scale
fahrenheit
a unit of temperature in which the freezing point of water is 32 degrees
radiation, conduction, convection
describe the three ways heat energy can be transfered
heated and expands (thermal expansion)
how does a thermometer work?
controls temperature mixing hot and cold air
how does a thermostat work?
equal to
if 25 g of hot water are added to 35 g of cold water, the heat lost by the hot water is (less than/greater than/equal to) the heat gained by the cold water
heat engine
A device that uses heat to do work and but is not 100% efficient and expels excess heat
temperature
A measure of the average molecular kinetic energy
conduction
A method of energy transfer between objects in contact due to temperature difference
convection
Heat that is transferred by movement of a fluid
thermal energy/internal energy
The total energy of the motion of the molecules contained in an object
heat
Thermal energy in motion
0th law of thermodynamics
This states that when two objects are in contact, heat will flow until they are in thermal equilibrium
heat should flow out
on a winder day, does cold flow into the house through the windows?