Unit 5 – Heat and Thermal Energy
NYS Standards:
4.2a Heat moves in predictable ways, flowing from warmer objects to cooler ones, until both
reach the same temperature.
4.2b Heat can be transferred through matter by the collisions of atoms and/or molecules
(conduction) or through space (radiation). In a liquid or gas, currents will facilitate the transfer of
heat (convection).
4.2c During a phase change, heat energy is absorbed or released. Energy is absorbed when a
solid changes to a liquid and when a liquid changes to a gas. Energy is released when a gas
changes to a liquid and when a liquid changes to a solid.
4.2d Most substances expand when heated and contract when cooled. Water is an exception,
expanding when changing to ice.
2.2k The uneven heating of Earth’s surface is the cause of weather.
Heat
-Heat is the transfer of energy between objects at different
temperatures.
Heat energy flows from higher temperature to lower
temperature.
 Two Types of Heat Objects
1. High temperature objects. Ex: Fire
2. Low Temperature objects. Ex: Ice
 Temperature
-Temperature is a measure of the average kinetic
energy of the particles in an object.
 Thermal Energy
-Thermal Energy is the energy that moves in heat
transfer.
o Higher Temperature = Higher Thermal Energy
o Lower Temperature = Lower Thermal Energy
 Two Things that Change Thermal Energy
1. Temperature
2. Amount of a substance
 More moving particles = more thermal
energy.
The more movement (Kinetic Energy) the molecules
have, the more Thermal Energy an object has!!
Reaching Thermal Equilibrium
 Thermal Equilibrium
-The point at which both objects in contact reach
the same temperature.
 NO change in thermal energy occurs when
thermal equilibrium is reached.
Energy Transfer
 Conduction
-Transfer of thermal energy from one substance
to another through direct contact.
 Particles collide, causing the kinetic energies
of colliding particles to INCREASE!!
 Particle speed increases and decreases until
they become equal giving us the same
temperature.
o Conductors
 Substances that transfer thermal energy well.
o Insulators
 Substances that do not transfer thermal
energy well.
 Convection
-Transfer of thermal energy by the movement of
a liquid or a gas.
 Causes higher-energy particles to separate
and rise, as they rise they cool, causing them
to call creating a Convection Current.
 Radiation
-The transfer of energy through matter or space
as electromagnetic waves.
 Visible Light and Infrared Waves
A review of the three types of energy transfer