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.

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: of heat transfer: Conduction Convection Radiation

TThe transfer of heat by direct contact between objects or particles. tch?v=tpkyuqial8o&t=92

But … What is conduction ???????? In non-metals: when heat is supplied to something, its atoms vibrate faster and pass on their vibrations to the adjacent atoms. In metals: conduction happens in the previous way and in a quicker way – some electrons are free to move, they travel randomly in the metal and collide with atoms and pass on the vibrations.

Heat transferred by the movement of molecules within a substance. Movement occurs from warmer areas to cooler areas. MRpWvsdw&t=45

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

Heat transferred through space. The Sun's radiation reaches the Earth through space. The sun’s rays causes sunburn.

Radiation

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

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.

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

A cooler (a thermos) is an insulator.

Applications  Solar panel: the sun’s thermal radiation is absorbed by a matt black surface and warms up the pipes containing water  Refrigerator: the freezer compartment is located at the top of the refrigerator. It cools down the air which then sinks. Any warm air rises to the top and then is cooled. This creates a convection current.

Convection currents create sea breezes. During the day the land is warmer and acts as heat source. During the night the sea acts as the heat source.

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. hotcold heat 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 here.

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.  Land breeze in the night and sea breeze in the day.