What tool is used to create curl in straight hair?

The tool used to create curl in straight hair is a curling iron. This heated styling tool is specifically designed to impart curls and waves to the hair. It works by wrapping sections of hair around a heated barrel, which effectively breaks down the hydrogen bonds in the hair structure, allowing it to take on the shape of the curl once cooled. The size of the barrel can also affect the type of curl produced, enabling stylists to achieve a range of looks from tight ringlets to loose waves.

While other tools, like hot rollers, can also create curls, they operate differently. Hot rollers utilize heat and the weight of the rollers to set the curl; however, they may not provide the level of control or instant results that a curling iron does. A straightening iron is designed specifically to straighten hair and would not be effective in creating curls. A hair dryer, while versatile for styling hair, primarily serves to dry or volumize hair and is not a dedicated tool for curling. Therefore, the best choice for creating curls in straight hair is indeed the curling iron.