Which tool is specifically used to determine vertical alignment?

The plumb bob is a tool specifically designed to determine vertical alignment. It consists of a weight attached to a string, which, when suspended, will point directly towards the center of gravity and provide a true vertical line. This makes it especially useful in construction and carpentry for ensuring that structures, such as walls and posts, are perfectly vertical.

The method behind the plumb bob's accuracy lies in the force of gravity. When the weight is free-hanging, it stabilizes and indicates a straight vertical line, allowing for precise alignment when building or setting up structures.

Other tools like the sliding T-bevel, square, and levels serve different purposes. A sliding T-bevel is used for transferring angles, while a square is mainly for checking and marking right angles. Levels, while useful in ensuring surfaces are flat or horizontal, do not specifically measure vertical alignment. Thus, the plumb bob stands out as the tool that effectively addresses this need.