Which device is thick at one end and tapers to a thin edge at the other end?

The correct answer is a wedge, which is a device specifically designed with one end thicker than the other, tapering to a sharp edge. This unique shape allows it to be driven into materials, effectively separating or lifting objects apart. The tapered edge provides the necessary force distribution, enabling the wedge to operate efficiently in tasks such as splitting, lifting, or securing objects in place.

While knives, screwdrivers, and chisels may exhibit tapering to some degree, they do not fit the description of being significantly thick at one end and tapering sharply to a thin edge in the same manner as a wedge. A knife typically has a blade that is sharp along its entire length, a screwdriver has a uniform thickness along the shaft with a flat or cross-shaped tip, and a chisel, while also tapering, is not utilized in the same manner as a wedge. Each of these tools serves different functional purposes, further distinguishing the wedge as the device that best matches the description given in the question.