Heat Transfer
& Phases
Intro Chapter
Energy
• Is the ability to do work and cause a
change.
• Can be transferred.
– Gases and liquids are made of molecules that are
constantly moving (kinetic energy). The faster
they are moving the more energy they have.
– Solids- molecules vibrate close together and
transfer energy.
Thermal Energy
• Is the total energy of motion in the
molecules of a substance.
• Gases are made of molecules that are
constantly moving. The faster they are
moving the more energy they have.
Temperature
• The average amount of energy of
motion in the molecules of a
substance.
• It is a measure of how hot or cold
something is.
Speed of Molecules & Temp
•
What happens
to the speed of
the molecules
when
temperature is
increased?
Speed of Molecules & Temp
•
What happens
to the speed of
the molecules
when
temperature is
increased?
Speed of Molecules & Temp
•
What happens
to the speed of
the molecules
when
temperature is
increased?
Speed of Molecules & Temp
•
What happens
to the speed of
the molecules
when
temperature is
increased?
Phase Changes
•
When a substance changes from one
state or phase to another.
• Solids
• Liquids
• Gases
•
Always occur with a change in heat,
which is energy.
Solids
•
Have definite shape and volume
• Solid to liquid- melting
• Solid to gas- sublimation
Liquids
•
Has a definite volume, and is able to
take the shape of the container
holding it.
• Liquid to solid- Freezing
• Liquid to gas- vaporation
• Boiling and Evaporation
Gases
•
A state of matter without definite
shape or volume.
• Phase Change• Gas to liquid- condensation.