Q > Where does water boil faster, in a confined space or an open area?

[charczstrife]

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naglibog lang ko ani gamay gud..

**onboard vessels, we use the vacuum as means to produce freshwater by boiling seawater.. rough estimation of boiling point of seawater is around 100*C.. but we can boil it only by 80*C by if we do this in a vacuum space.. so the lower the pressure, the faster we can boil water..

**theoritically, pressure is directly proportional to temperature..

so here is the question: Where does water boil faster, in a confined space or an open area?

naglibog lang ko gud kay kung mabukal og tubig sa balay kay moingon man sila nga mas dali daw mobukal ang tubig basta takoban aron matrap daw ang init.. so meaning, kung takoban kay makabuild up og pressure.. kung magbuild up pressure, mas dugay pabukalon.. if wala pud takob, mening open space, makatakas sad ang init so mahog ra pud nga dugay mabukal kay mas dugay man moinit ang tubig.. so unza man jud mas dali mobokal ang tubig?

hope naay makaexplain scientifically ani kay medyo libog.. hehehe... tnx daan..

[rodsky]

I just realized your question was about takloban or not takloban. It's a misconception nga if wala'y taklob, mas "gamay" ang heat nga will affect the boiling point of the water--same ra gihapon na--you just think nga pag takloban kay you're using the idea nga if you are in a closed room, mas init ang room Mas dako gihapon ang effect sa direct heat on the water, rather than the heat of the air inside the closed container.

Now, about location...wala ma'y effect ang location (with respect to indoor vs. outdoor)--only if the altitude is significantly different (i.e. boiling point at sea level is around 100°C and at high altitudes mga 96°C, which is why kinahanglan you have to cook your hard boiled egg longer sa bukid-bukid (high altitude) nga lugar, because sa taas nga places, mas lower man ang air pressure.

However, if we're talking about the effect of the surroundings on the heating agent (i.e. the fire/heat source used to boil the water), naturally indoors would keep the heat in, and if you're boiling using firewood as fuel, outdoors, there are many environmental factors (i.e. wind, rain, humidity) that can perhaps affect your heat source/fire, but I think the factor is minimal.

Other things that affect boiling point of water are:

Salt: Salt, sugar, and practically any other substance elevates the boiling point and therefore shortens cooking time. The difference in temperature between unsalted and salted water (one teaspoon of salt per quart of water) is about 1° to 2° F, a difference that can be critical in cooking situations demanding exactness.

Hard Water: Hard water defines water with a high level of dissolved mineral salts. Therefore, hard water boils at a higher temperature. The difference in the boiling point between typical supplies of hard and soft water is about a degree or two.

Alcohol: Alcohol has a lower boiling point that water (about 175° F as compared with 212° F). If you dilute water with alcohol, the mixture will have a lower boiling point up until the alcohol completely evaporates. Should you decide to alter an existing recipe by substituting a fair portion of wine for some of the water, remember to extend the cooking time by 5 to 10 percent depending on the alcohol strength of the wine and the heaviness of your touch.

Weather: The boiling point of water is a degree or two lower on stormy, as opposed to fair, weather days. Consequently, boiled food will take longer to cook on a stormy day (again, because of the fact nga when there is a storm, ang tawag gani sa mga weather forecasters kay "Low Pressure Area").

Different Size Pans: Will a given volume of water boil at a higher temperature in a tall, narrow pot than in a short, wide one? Yes. since the tall, narrow pot has a great depth, its bottom-lying water is under greater pressure from the water above it than is the water at the bottom of the short, wide pot. The greater the pressure, the high the boiling point. The difference is approximately 1° F.

(source: How To Boil Water, Boiling Points of Water, High Altitude Boiling Water, Sea Levels vs. High Altitude Water Temperatures)

-RODION

[treize]

This question was already proven by a lot of Chefs. Your water will boil faster when covered since you contained the heat inside thus raising the temperature faster and boiling the water faster..

[THE SKULLS]

Closed container para dali.

[tikud]

This question was already proven by a lot of Chefs. Your water will boil faster when covered since you contained the heat inside thus raising the temperature faster and boiling the water faster..

Chefs cover the pots to increase temperature by building up pressure. Mas dali ma luto ang food.
Boiling point doesn't matter to the Chefs but the temperature.

It is a misconception to cover the pot so dali ra mo bukal but rather mas taas ang temperature na maabot for a certain period.

no matter how much you heat an open container with water it will just evaporate at 100 deg C. It won't go higher than that unless Catalysts are added such as sugar or salt.

But if you cover a container filled with water, the temperature inside the container will exceed 100 deg C for the pressure increases. Mao na mas dali ma luto ug ma lata ang beef sa pressure cooker than an open container.

You have to understand that in order for WATER to boil, its temperature (of the saturated vapor pressure) should be equal to the surrounding athmospheric pressure.

Water
The vapor pressure reaches the standard sea level atmospheric pressure of 760 mmHg at 100°C.
Since the vapor pressure increases with temperature, it follows that for pressure greater than 760 mmHg (e.g., in a pressure cooker), the boiling point is above 100°C and

for pressure less than 760 mmHg (e.g., at altitudes above sea level), the boiling point will be lower than 100°C.

Producing potable water from seawater by boiling it in a vacuum is employed for economic reasons. under normal conditions, seawater will boil over 100 deg Celsius. Temperature is not the concern of distillation but rather the condensation to produce potable water thus efficiency is obtained.

Water will boil in high temperature when placed in a container since pressure will build up.
Dali ma luto pero dugay mo bukal if close and container (assuming less evaporated water can escape).

Bottom line boiling point is dependent on the athmospheric pressure and the water vapor pressure.
Where pressure is directly proportional to temperature.
Your water inside a cup inside a microwave maybe 110 deg C, but you can't see it boiling because the heat is from the outside of the water surface to the core of the container. mild explosion will occur when you suddenly subject the heated water to athmospheric pressure coz of abrupt boiling will occur.
so it is recommended not to overheat your water in a microwave or take out the cup right after heating.

[rodsky]

Now I wish iStorya.net had a dislike button. I seriously dislike my own post above

-RODION

[tikud]

Now I wish iStorya.net had a dislike button. I seriously dislike my own post above
-RODION

Sir Rodsky, sakto man ang imo gui post. In fact igo ra nako gui expand.

Dugay na ka wala naka balik ako office Sir.
Maybe you can drop by again and let's have coffee. duna ko Sang Tao ug Suc Song Trung nguyen Ca' Phe' Rang Xay diri ready for fresh brewing.

[fern-pewee]

d ba depende unsa ka kusog imo kalayu:P

[fritzd]

naglibog lang ko ani gamay gud..

**onboard vessels, we use the vacuum as means to produce freshwater by boiling seawater.. rough estimation of boiling point of seawater is around 100*C.. but we can boil it only by 80*C by if we do this in a vacuum space.. so the lower the pressure, the faster we can boil water..

**theoritically, pressure is directly proportional to temperature..

so here is the question: Where does water boil faster, in a confined space or an open area?

naglibog lang ko gud kay kung mabukal og tubig sa balay kay moingon man sila nga mas dali daw mobukal ang tubig basta takoban aron matrap daw ang init.. so meaning, kung takoban kay makabuild up og pressure.. kung magbuild up pressure, mas dugay pabukalon.. if wala pud takob, mening open space, makatakas sad ang init so mahog ra pud nga dugay mabukal kay mas dugay man moinit ang tubig.. so unza man jud mas dali mobokal ang tubig?

hope naay makaexplain scientifically ani kay medyo libog.. hehehe... tnx daan..

The problem is not very complicated. You have to realize that when you are boiling water, you are providing external heat energy from your flame at the bottom of the pot. If you are familiar with the equation pV=nRT, then this is an incomplete model for our system. It only holds true if you have a constant energy with your system.

Now what about the boiling water? We have a constant heat source. We are always adding energy to the system. If the pot is an open system (no cover), then water at the surface can evaporate and escape the pot. Overall, the system will try to reach the room temperature because your pot is still coupled to the environment which is a very very big heat reservoir. In this case, your water is still boiling.

Now, what about if we cover the pot, in this case, you are decoupling your system to the environment and you are constantly adding heat energy from the system from the flame at the bottom of your pot. With the cover, you are not allowing evaporated water to escape. Heat energy flow to the environment is much much slower because the evaporated water will have to re-condense below the surface of the cover and heat will escape through thermal conduction of the pot external body. In short, when you cover the pot, you don't allow energy to escape right away. You are containing energy. Energy within the pot, has to go somewhere so it goes to pressure.
Pressure= Energy(t)/Volume
This is the simplest way to solve this problem without having to go through the Heat transport equation. Take note, I write Energy as a function of time because we are always constantly adding energy to the system. Volume is constant therefore we accumulate pressure. As a result, the entire water from bottom to the surface becomes one big system in the pot and water violently goes from liquid and gas and vice versa. With the pot's volume, it is never possible to get all water in the vapor phase. But you store a lot of energy in your system, that when you open it, you experience a huge load of steam.

Anyway, I hope this helps.