round flasks

In the Laboratory

• Uniform heating of contents
• Suitable for use under vacuum

Multi-neck Flask

• Destillation
• Extraktion
• Synthese

Appropriate Use of the Round-bottom Flask

• In physics lessons to demonstrate the cobbler's ball (see also "Useful information")

Round-bottom flasks have a spherical body and a cylindrical neck. A tripod or laboratory stand is required for stability. The round shape allows for even heating of the contents. Unlike Erlenmeyer and vertical flasks, round-bottom flasks can safely be used under vacuum without risk of implosion.
Multi-neck flasks, which are a type of round-bottom flask, come with two, three, or more openings featuring ground joint sleeves. These openings allow simultaneous connection to a condenser, stirrer, measuring devices, or feeds, making them useful for processes like distillation, extraction, and synthesis.
Flasks can be cleaned manually in an immersion bath or mechanically in a dishwasher.

The Cobbler's Ball Explained:
A round-bottom flask can also be used as a cobbler's ball. To do this, fill the narrow-necked round-bottom flask with water and seal it with a cork stopper.
Before the advent of electric light, cobblers used this tool to focus the diffuse light from the sun, gas, or oil lamps, thereby illuminating their workspace on dimly lit days. The cobbler's ball also filtered heat radiation from the light source, enabling work with temperature-sensitive materials near a strong light source.