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Rolling boil of water in an electric kettle. Boiling or ebullition is the rapid phase transition from liquid to gas or vapour; the reverse of boiling is condensation.Boiling occurs when a liquid is heated to its boiling point, so that the vapour pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding atmosphere.
The atmospheric pressure boiling point of a liquid (also known as the normal boiling point) is the temperature at which the vapor pressure equals the ambient atmospheric pressure. With any incremental increase in that temperature, the vapor pressure becomes sufficient to overcome atmospheric pressure and cause the liquid to form vapor bubbles.
Bumping is a phenomenon in chemistry where homogeneous liquids boiled in a test tube or other container will superheat and, upon nucleation, rapid boiling will expel the liquid from the container. In extreme cases, the container may be broken.
Vacuum Sugar Apparatus at The Great Exhibition, 1851. Vacuum evaporation is the process of causing the pressure in a liquid-filled container to be reduced below the vapor pressure of the liquid, causing the liquid to evaporate at a lower temperature than normal.
Superheating can occur when an undisturbed container of water is heated in a microwave oven. At the time the container is removed, the lack of nucleation sites prevents boiling, leaving the surface calm. However, once the water is disturbed, some of it violently flashes to steam, potentially spraying boiling water out of the container. [6]
As the gas continues to expand, the gas will then bubble through the liquid, boiling. The fact that the liquid is volatile (easily vaporized) makes the hand boiler more effective. Adding heat to the liquid produces more gas, also increasing pressure in the closed container. [2] Sometimes a hand boiler is used to show properties of distillation.
Inside a shaking water bath A water bath operating at 72°C. A water bath is laboratory equipment made from a container filled with heated water. It is used to incubate samples in water at a constant temperature over a long period of time.
Boil-in-bags are a form of packaged food products in which bagged food is heated or cooked in boiling water. Plastic bags can be solid and impermeable for holding frozen foods; alternatively, bags can be porous or perforated to allow boiling water into the bag. Food packaged in this manner is often sold as boil-in-the-bag. [1]