The three main sources of Earth's internal heat are: 1) primordial heat left over from the planet's formation 4.5 billion years ago, 2) radiogenic heat from radioactive decay of elements in Earth's interior, and 3) frictional heating caused by denser core materials sinking to the center. Heat is transferred within Earth by conduction through stationary matter, convection through fluid movement like magma or molten iron, and minimally by radiation.

1. EARTH'S INTERNAL HEAT

2. THREE MAIN SOURCES
OF HEAT
PRIMORDIAL HEAT -
the left over-heat
from the formation
of our planet about
4.5 billion years ago
and accreted, which
has not yet been
lost.
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3. Radiogenic
heat
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4. Frictional
heating
Caused by denser core
material sinking to the center
of the planet.
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5. COMPOSITION
OF EARTH'S
INTERNAL
HEAT

6. THREE METHODS OF HEAT TRANSFER
Conduction is a
heat transfer
through stationary
matter by physical
contact.

7. Convection
• Is the heat transfer by
the macroscopic
movement of a fluid
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8. Radiation
Is the least important mode of
heat transport in the Earth.