What type of energy transformation occurs in the log as it burns?

When a log burns, it undergoes a transformation whereby the stored chemical energy in the wood is released in the form of thermal energy (heat) and light energy (flames). This process is a type of combustion, where the chemical bonds in the wood are broken, leading to a chemical reaction with oxygen that produces heat and light.

In the context of energy types, chemical energy is the energy stored in the molecular bonds of substances. During the burning process, this energy is released as heat (thermal energy) and is also emitted as visible light, particularly in the flames that we observe. Therefore, the correct answer highlights the transformation from chemical energy to thermal and light energy, encapsulating the essence of what occurs during combustion.