Note the stopcock, glass tube at the left rear, and ground glass joint in this pressure-equalizing dropping funnel.

A dropping funnel is a type of laboratory glassware used to transfer fluids. Laboratory glassware refers to a variety of equipment traditionally made of Glass, used for Scientific experiments and other work in Science, especially They are fitted with a stopcock which allows the flow of to be controlled. A stopcock is a Valve used to restrict or isolate the flow of a liquid or gas through a pipe. 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.

Pressure-equalizing dropping funnels have a ground glass joint surrounding the stem, allowing the dropping funnel to be fitted directly to the receiver such as a round bottom flask. Ground_glass_joint_closedjpg|right|thumb|The same joint closed Round-bottom flasks (also called round-bottomed flasks and Erlenmeyer Bulbs) are types of Flasks having spherical bottoms used as Laboratory glassware If the receiver did not have another opening, the flow of fluid will rapidly come to a halt due to the built-up pressure. Thus, a narrow-bore glass tube is connected from the joint to the top of the dropping funnel to allow the overpressure to be relieved.

See also

• Separatory funnels are similar in shape and design, and may be used as dropping funnels. A separating funnel, also known as separation funnel, separatory funnel, or colloquially sep funnel, is a laboratory glassware used in Liquid-liquid They do not have the ground glass joint at the stem.