Arga Dwi Arfiyanto
EK C / 04
THE BOILING POINT OF WATER
Boiling (also called ebullition), a type of phase transition, is the rapid vaporization of a liquid, which typically occurs when a liquid is heated to its boiling point, the temperature at which the vapor pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding environmental pressure.
Thus, a liquid may also boil when the pressure of the surrounding atmosphere is sufficiently reduced, such as the use of a vacuum pump or at high altitudes. Boiling occurs in three characteristic stages, which are nucleate, transition and film boiling. These stages generally take place from low to high surface temperatures, respectively.
The boiling point of a liquid is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid. The normal boiling point (also called the atmospheric boiling point or the atmospheric pressure boiling point) of a liquid is the special case in which the vapor pressure of the liquid equals the defined atmospheric pressure at sea level, 1 atmosphere
The boiling point of water means a point of temperature when the water has boiled in all surfaces. In daily life we can find it when we are boiling the water.
If large bubbles are rising from the bottom of the pot to the surface, the water is boiling. NOTE: Small bubbles that stay at the bottom or sides of the pot are air bubbles present in the water; they don't necessarily indicate that boiling is imminent. Wait for bubbles that rise to the top of the pot.
The temperatures of water:
Water boils at 212°F (sea level), and simmers at 190°F.
Tepid Water - 85 to 105°F. The water is comparable to the temperature of the human body.
Warm Water - 115 to 120°F. The water is touchable but not hot.
Hot Water - 130 to 135°F. The water is too hot to touch without injury.
Poach - 160 to 180°F. The water is beginning to move, to shiver.
Simmer - 185 to 200°F. There is movement, and little bubbles appear in the water.
Slow boil - 205°F. There is more movement and noticeably larger bubbles.
Real boil - 212°F. The water is rolling, vigorously bubbling, and steaming.
The factors that influence the boiling points of water. They are:
Salt: Salt, sugar, and practically any other substance elevate the boiling point and therefore shorten cooking time.
Weather: weather can influence the boiling point of water, for example boiled food will take longer to cook on a stormy day.
Different Size of Water Containers can change the boiling point of water. If we boil water in a short and wide water container, the water will boil at lower temperature. But if we boil it in a tall and narrow container, the water will boil at higher temperature.
Altitude: For each thousand feet above sea level, the boiling point of water drops almost 2° F.
The use of boiling points of water. We usually use the boiling points of water for sterilizing, pasteurizing, cooking, burning the ceramics, boiling the ‘Batik’ cloths, As the alternative energy source by the energy of steam, etc, Boiling has several advantages. It is safe and simple, and it is appropriate for large-scale cookery. Older, tougher, cheaper cuts of meat and poultry can be made digestible. Nutritious, well flavored stock is produced. Also, maximum color and nutritive value is retained when cooking green vegetables, provided boiling time is kept to the minimum.
On the other hand, there are several disadvantages. There is a loss of soluble vitamins from foods to the water, and boiled foods can look unattractive. Boiling can also be a slow method of cooking food
In places where the available water supply is contaminated with disease-causing bacteria, boiling water and allowing it to cool before drinking it is a valuable health measure. Boiling water for a few minutes kills most bacteria, amoeba, and other microbial pathogens. It thus can help prevent cholera, dysentery, and other diseases caused by microorganisms.
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