The term “dropping funnel” usually describes a piece of chemistry lab apparatus. The tube is long and narrow, with a stopcock located at the bottom. It is frequently used to accurately control the rate of addition by slowly adding liquids to a reaction vessel. This can be crucial in processes where a rapid reaction or other unfavorable effects could result from adding a liquid too quickly. They are frequently employed in procedures such as titrations or the gradual addition of reagents to reaction mixtures.