Conical flask
A conical flask is a glass flask shaped like a cone, with a wide bottom and a narrow neck.
What is it for?
It is great for mixing and swirling liquids, because the sloping sides stop them from splashing out.
How to use it
Hold it by the neck and gently swirl it in small circles to mix what is inside.
🥽 Safety tip: Never push a stopper in tightly while it is being heated, because the air inside expands and needs a way out.
Fun fact from Fizzy: It is also called an Erlenmeyer flask, after the German chemist Emil Erlenmeyer, who invented it in the 1860s.
Why the cone shape helps
The wide, flat bottom makes the flask hard to knock over, and the narrow neck means less liquid can escape as a gas or splash out when you swirl it. The neck is also easy to close with a stopper, a ball of cotton wool or a piece of foil.
Because you can swirl it without spilling, the conical flask is the flask chemists use when they add one liquid drop by drop from a burette and watch for a colour change.
Where you would see one
Conical flasks are used in school labs, in hospitals for growing samples, and in factories that make medicines. In films and cartoons, the bubbling flask a scientist holds up is very often a conical flask.