Which device is primarily used for heating substances in a lab?

The Bunsen burner is primarily used for heating substances in a laboratory setting. This device produces a controlled flame that can be adjusted for temperature and size, making it ideal for various heating applications, such as sterilizing equipment, boiling liquids, and conducting combustion reactions. Its design allows for efficient heat transfer, and the ability to mix air with the gas allows for a hotter flame compared to other heat sources.

Other devices mentioned serve different primary purposes. For instance, a microscope is used to magnify small objects for observation, a calorimeter measures the heat involved in chemical reactions or physical changes, and a centrifuge is used to separate components of a mixture based on density through high-speed spinning. Each of these tools plays a distinct role in laboratory work, but the Bunsen burner specifically addresses the need for direct heating.