Final answer:
In permanent waving, wrapping hair at an angle other than perpendicular to the rod is an off-base wrap, which creates a softer wave with less volume at the scalp, differing from the traditional perpendicular wrap.
Step-by-step explanation:
In permanent waving, the technique where hair is wrapped at an angle other than perpendicular to the length of the rod is known as an off-base wrap. This method differs from the traditional perpendicular wrap, where the hair is wrapped directly around the rod at a 90-degree angle.
In off-base wrapping, the angle is less than 90 degrees, which results in less volume at the scalp and a softer wave pattern. A perm, or permanent wave, involves breaking and reforming the hair's disulfide bonds using chemicals, which allows the hair to take on a new shape. This can result in curls or waves that last several months.
Permanent waves and temporary waves both alter the hair's natural structure but through different mechanisms and duration. Temporary waves rely on disrupting hydrogen bonds, which can be reversed by washing the hair, whereas perms alter the more durable disulfide bonds for a long-lasting effect.