Physics 25-26 2.0 Flashcards
Exchanges both matter and energy
Open System
Cannot exchange matter but can exchange energy
Closed System
Cannot exchange either matter or energy
Isolated System
Work involves the movement of
Matter from one location to another
Heat is a transfer of
thermal energy from one location to another
Heat added to a system
by its surroundings
Work can be done on a
system by its surroundings
Work done on the system by the surroundings is considered
positive work because the energy of the system increases
Heat can flow out of the
system to its surroundings
Work can be done by a
system on its surroundings
Work done by a system on its surroundings considered
negative work because the energy of the system will decrease
That the total energy, including heat in a system and its surroundings remains constant
First Law of Thermodynamics
supported by
Joules experiments
When heat is added to a system, some of the
energy goes into increasing the internal energy of the system
Heat added to the system =
Mechanical energy + heat
The amount of heat put into a system must equal the amount
of mechanical energy plus heat lost by the system
The direction of energy flow in natural processes
The Second Law of Thermodynamics
Heat always flows naturally from a
hot object to a cold object but never naturally from a cold to a hot object
Flows from a high temperature area to a low temperature
Heat engine
A heat engine is a device that
converts heat into mechanical energy
Only some of the input heat can
be converted to mechanical energy
The remaining heat is expelled
as exhaust heat
Devices that convert heat into mechanical energy
Heat Pump
A thermo – electric converter
Heat engines
Christian Huggens recognized that a successful reciprocating
needs a force to drive the piston forward and a force to pull back
Gases generated by an explosion inside
the engine drove the piston forward
Hazards of explosion and because there was no
Powerful internal mechanism to pull the piston back so the machine could operate continuously
Otto van Guerike demonstrated forces of
vacuums
Denis Papin designed the
first heat engine
Papin did not pursue the development of his engine because he
had difficulty masking the large drum which the water was to be heated
Thomas Saverg invented the
first successful steam powered pump
The pump could life water
to a height of 6m
The steam would be under to much
pressure without the boiler exploding
Thomas Newcomen invented
the next heat engine
Cycle of heating and cooling the cylinder was
inefficient and the engine required a lot of heat to function
James Watt was asked to repair
Thomas Newcomen’s machine
Could not be made to be
small enough to replace
Heat that was created was
lost to the surroundings
Robert Steele revived Huygen’s idea by
Using gas produced by an explosion
Phillipe Lebon used coal gas ignited
by an electrical spark inside the engine
Very inefficient and could not produce
enough force to operate a machine
Christin Huggens
Gunpower Engine
Otto von Guerike and Denis Papin
The heat engine
Thomas Savery
The Savery Engine
Thomas Newcomen
The newcomen engine
James Watt
The Watt Engine
Robert Steele and Phillppe Lebon
Internal Combustion Engine
N.A Otto and Eugen Langen improved the efficiency of the engine
by compressing the coal gas – air mixture before ignition
They developed the
four-stroke internal combustion engine
Used coal gas as fuel which didn’t burn
very hot so the engine was not that powerful
Gottlieb Daimler designed a petroleum fuelled
internal combustion engine that used gasoline
The initial energy source
Energy input
Desired energy needed to do the work
Useful energy output
The work the machine is supposed to do
Useful work output
Radiant energy
from the sun emitted by the hydrogen
Travels by
electromagnetic radiation
Directly through
plants or earth’s surface
Heating of the surface of Earth by
the sun
Caused convections currents of
air or wind
Surface water is heated
by the sun ie biomass
Any form of
organic matter
Solar energy
sources
Store energy from the sun
through photosynthesis
Fossil fuels are
indirects solar energy
non-solar energy sources
no relationship with the sun
Fission reactions can be controlled by
the CANDU reactor
Movement of ocean water
Tidal energy
Caused by gravitational pull
by the moon
Renewable sources are
continually and infinitely available ie biomass
Non-renewable sources are
limited and irreplaceable ie Nuclear and Fossil Fuel
Popular
Energy demand
Many societies use non-renewable resources
Energy demand
