1. A Source of Heat:
* The Earth's Interior: The Earth's core and mantle are extremely hot, providing the energy to melt rock.
* Volcanoes: Volcanic activity brings magma to the surface, where it cools and solidifies.
* Plate Tectonics: The movement of tectonic plates can cause friction and heat, leading to melting.
2. Molten Rock:
* Magma: Molten rock found beneath the Earth's surface.
* Lava: Molten rock that has erupted onto the Earth's surface.
3. Cooling and Solidification:
* Intrusive Igneous Rocks: Magma that cools slowly beneath the surface, allowing large crystals to form.
* Extrusive Igneous Rocks: Lava that cools rapidly on the surface, resulting in smaller crystals.
4. Composition:
* The type of magma or lava: The chemical composition of the molten rock will influence the minerals that crystallize and the final rock type.
In summary, to form an igneous rock, you need a source of heat to melt rock, the molten rock itself, and a process of cooling and solidification.
