Dropping funnel
![Note the stopcock, glass tube at the right, and ground glass joint in this pressure-equalizing dropping funnel. An ordinary dropping funnel lacks the pressure-equalizing glass tube at the right side.](/Images/godic/202501/10/Ampoule_à_brome5021.JPG")
A dropping funnel is a type of laboratory glassware used to transfer fluids. They are fitted with a stopcock which allows the flow to be controlled. Dropping funnels are useful for adding reagents slowly, i.e. drop-wise. This may be desirable when the quick addition of the reagent may result in side reactions, or if the reaction is too vigorous.