This document discusses heat transfer and the three main methods: conduction, convection, and radiation. Conduction involves the direct contact transfer of heat between objects. Convection refers to the transfer of heat by the movement of molecules within a substance from warmer to cooler areas. Radiation involves the transfer of heat through space, such as the sun's rays causing sunburn. The document provides examples and descriptions of each type of heat transfer.

1. A Form of energy that is related to the K.E.
of molecules. The motion of molecules
produces heat. The more motion, the more
heat is generated.

2. Heat Transfer
 The movement of heat (thermal
energy) from a warmer object to a
colder one.
 Heat is a moving energy.
There are three forms
of heat transfer:
 Conduction
 Convection
 Radiation

3.  The transfer of
heat by direct
contact
between objects
or particles.

4.  Heat transferred
through space.
 EXAMPLE: The
sun’s rays
causing a
sunburn.

5.  Heat transferred by
the movement of
molecules within a
substance.
 Movement occurs
from warmer areas to
cooler areas.

6.  The movement of a substance that is
caused by differences in temperature and
density.
 Examples: wind
boiling water
 Nature wants everything
to be balanced !!!

7.  Conductors are materials that
transfer heat easily.
 Examples:
metals like copper
and gold.

8. A pot is a conductor.
 The molecules in a
conductor are
close together.
This allows the
heat to move to all
parts of the pot and
the stew in the pot.

9.  An insulator is a
material that does not
transfer heat easily.
 Examples:
liquids and
gases
jackets
pots handles

10. A cooler (a thermos) is an
insulator.
 The molecules in
an insulator are
far apart. This
helps prevent
heat from flowing
in or out.

11. Thermal Equilibrium
Two bodies are said to be at thermal equilibrium if they are at the same
temperature. This means there is no net exchange of thermal energy
between the two bodies. The top pair of objects are in contact, but since
they are at different temps, they are not in thermal equilibrium, and
energy is flowing from the hot side to the cold side.
hot coldheat
26 °C 26 °C
No net heat
flow
The two purple objects are at the same temp and, therefore
are in thermal equilibrium. There is no net flow of heat energy

12. Question
What type of heat transfer?
 Warm air mass, bringing a change in the weather.
 Wire getting hot from an electric appliance.
 Heating a room with a fireplace.
 Egg cooking in a frying pan.
 Roof of a house becoming hot.