Milady Cosmetology Practice Exam

What type of waves require an external heat source for activation?

1. Exothermic

2. Endothermic

3. Thermal

4. Chemical

The correct answer is: Endothermic

The correct response corresponds to endothermic waves, which are types of chemical reactions that absorb heat from their surroundings to initiate a process. In the context of hairchemistry, endothermic waves require an external heat source, such as a hooded dryer or a flat iron, to activate the waving solution and effectively alter the hair's structure. This process involves the application of a perm solution that penetrates the hair shaft, and once heat is applied, it enables the disulfide bonds in the hair to break down and reform in a new shape, creating curls or waves. Without the necessary external heat, these reactions would not occur, and the desired results wouldn't be achieved. Other types of waves, such as exothermic waves, generate their own heat during the chemical reaction and do not require an external heat source. Thermal waves typically refer to heat-related processes but do not specify the requirement for an external source like endothermic waves do. Chemical waves may encompass a broader range of chemical reactions without the explicit heat requirement needed by endothermic waves.