Final answer:
The heating and rising of the mantle material through cooler parts is an example of convection, a key driver in plate tectonics and geological activity such as volcanic eruptions.
Step-by-step explanation:
When the heated part of the mantle rises through the cooler part, it is an example of convection. This process occurs because heat within the Earth's mantle causes the hotter, less dense material to rise, while cooler, denser material sinks due to gravity. This convection movement facilitates the transfer of heat and is a driving force behind plate tectonics, affecting the movement of the Earth's crust. An example of this can be seen in lava rising in a volcano, which is driven by the same principles that cause mountain ranges to float on the higher-density crust and mantle beneath them.
The actual phenomenon, where heat is transported from a warm region (the interior of Earth) to a cooler region (upper mantle), emphasizes the fluid characteristics of Earth's geology, despite its seemingly solid nature. As this process repeats, it plays a vital role in the dynamics of our planet's structure and affects geological formations and events on a global scale.