Final answer:
A figure eight on a bight is a knot used to create a secure loop at the end of a rope. It is unrelated to the described activity of swinging an object on a string, which is associated with demonstrating centripetal force in physics.
Step-by-step explanation:
A figure eight on a bight is used to create a secure loop at the working end of a rope. This type of knot is often used in climbing and sailing for its strong, reliable, and easy-to-inspect qualities. The procedure you've described swinging an object tied to a string in a horizontal circle does not directly relate to the tying of a figure eight on a bight, but it could describe an activity to demonstrate centripetal force, which is a concept from physics.