Heat and temperature
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14. Heat transfer. Sumary

Summary


• Heat is transferred by conduction, convection and radiation.

Conduction is the transfer of thermal energy between particles of matter that are touching.
Thermal energy is always transferred from particles of warmer matter to particles of cooler matter.

• When particles of warmer matter collide with particles of cooler matter, they transfer some of their thermal energy to the cooler particles.

Convection is the transfer of thermal energy by particles moving through a fluid.
Thermal energy is always transferred from an area with a higher temperature to an area with a lower temperature.

• Moving particles transfer thermal energy through a fluid by forming convection currents.

Convection currents move thermal energy through many fluids, including molten rock inside Earth, water in the oceans, and air in the atmosphere.

Thermal radiation is the transfer of thermal energy by waves that can travel through air or even through empty space.
This is how thermal energy from a fire is transferred to your hands and how thermal energy from the sun is transferred to Earth.

Everything radiates thermal energy, even objects that aren’t very warm.

The video sumarizes the three ways heat is transferred.

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