Download Heat and the Conservation of Energy

Heat and the Conservation of
Energy
Chapter 9
Part 2
Heat
Like work Heat is a means of transferring energy
from one to another object or substance.
Objects contain Internal energy, not heat…
Heat is the flow of internal energy
From one object or substance
Into another.
Heat is measured in Energy units:
Joules, Calories, Btu’s & therms
Thermal Conduction
Thermal conduction is
when heat is passed
along as the motion
of one atom does
work on an adjacent Conductors are materials that
atom making it move conduct heat quickly
Metals are good thermal
conductors
Ceramics, fiberglass etc do not,
they are thermal insulators
Liquids and Gases are good
insulators because atoms are
more distant
Convection and Radiation
Convection is when heat
moves with a moving
Fluid
Radiation is when heat is
transferred by
electromagnetic waves
Usually infrared light
Conservation of Energy, Work and Heat
In a closed system (no work or heat flows in or out)
Total Energy does not change
ΔKE + ΔPE + ΔU =0
Work done on a system will change the total
energy of the system.
As long as no heat leaves the system
W = ΔKE + ΔPE + ΔU