Which tool is primarily used to aid in heating samples in a laboratory?

The hot plate is indeed the primary tool used in laboratories for heating samples. It provides a controlled source of heat that allows researchers to precisely warm liquids and other materials to desired temperatures without the risks associated with open flames. Hot plates are designed for safety, efficiency, and ease of use. They often allow for uniform heating across the surface, ensuring even temperature distribution, which is critical when conducting experiments that require specific thermal conditions.

In contrast, the other tools mentioned serve different purposes. A Scoopula is used for transferring solid materials, and a stopcock is a device used to control the flow of liquids in vessels such as flasks or burettes. A cylindrical flask is a container used to hold liquids but does not itself provide any heating capability. Therefore, while each of these tools plays an essential role in laboratory work, the hot plate stands out as the dedicated device for heating samples.