A flask is a container designed to hold liquids, and the word describes several different types depending on what you need to carry.

The most common kind is a small, flat bottle that fits easily in a pocket or bag. People use flasks to carry water on hikes, or adults might carry hot chocolate, tea, or other drinks. These flasks often have a screw-on cap and are made of metal or sturdy plastic. Their slim, curved shape makes them portable and convenient.

In science labs, a flask means something quite different: a glass container used for mixing chemicals or heating liquids during experiments. The most recognizable is probably the Erlenmeyer flask, which has a wide base that narrows to a thin neck at the top. This shape keeps liquids from splashing out when you swirl them, and the narrow opening makes it easy to add a stopper. Scientists use different flask shapes for different purposes: round-bottom flasks for heating, volumetric flasks for precise measurements, and flat-bottom flasks for simple mixing.

Today, whether you're carrying soup in your lunchbox or conducting a chemistry experiment, you're using a flask.