What type of heat source is required to activate an endothermic wave?

An endothermic wave requires an outside heat source to activate its chemical process. This type of waving solution absorbs heat from the surrounding environment to initiate the necessary reactions for the hair structure to change during the perming process.

In practical terms, hair treated with an endothermic perm will often be wrapped and then allowed to sit under a hooded dryer or similar device that provides the necessary warmth to facilitate this process. To achieve the desired curl or wave, the absorption of this external heat is essential.

The other options do not apply in the same way for an endothermic process. Convection heat sources and direct heat sources can generally be associated with exothermic processes or other types of waves, while electrical heat sources may not provide the consistent, surrounding warmth that is critical for the effective activation of endothermic waving solutions.