What is the primary source of energy released when burning a log?

The primary source of energy released when burning a log comes from the energy stored in the log itself. This energy is primarily in the form of chemical potential energy, which is contained in the molecular bonds of the wood. When the log is ignited, a combustion reaction occurs, breaking these bonds and releasing energy in the form of heat and light.

The combustion process transforms the stored energy into thermal energy, which contributes to the heat that is felt and the flames that are observed. This is a fundamental concept in chemistry and biology, as it illustrates how living organisms and materials store energy in chemical bonds, which can then be released under the right conditions. Understanding this process is crucial for studying energy flows in ecosystems, as well as the practical applications of combustion in energy production.