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Posts Tagged ‘air’

What Makes the Clothes Placed inside a Dryer Dries Up Faster than Clothes Hanged Outside?

May 11th, 2009

In a dryer, the clothes are mechanically dried up squeezing the clothes to separate from water forcefully, while in hanging, the clothes dry up in a natural way. All the water that drips from the clothes goes to the air, that’s it.

Now just think where all the water goes from billions of clothes dried up daily in the world by hanging them outside under the heat of the sun. Under broad daylight and even if small amount of rays is coming from the sun, all the water become part of the air and go to the atmosphere in a process called evaporation.

When the water goes to the air, it is hidden by the clouds in the sky and the clouds become white, some are gray and others become dark. The clouds are white because they are not yet ripe to fall as rain. Some are gray because they have already formed some droplets of water that are ready to come back to the earth. Others are dark because anytime, they will fall as heavy rains.

These rains form part of the rivers, oceans, lakes and other waterways. Water fall as snow during winter so, it becomes a cycle from the earth and goes back to the earth. The air is saturated in the clouds that it’s hard for it to hold water because of the low temperature. Hence, the droplets of water in the clouds start growing combining with the extra water in the moist air of the clouds.

When these water droplets become so large by constantly hitting each other during a thunderstorm, they are pulled by the gravity of the earth. Still, when they become larger by combining with other droplets, they fall out on the earth as rain.

Supposing a big container filled with water is placed in an open space but the temperature does not change, would the process of evaporation be slower? Humidity depends on the temperature and the air’s vapor pressure controls the process. Proportionality is not regarded as a linear inverse; the density of the air affects the rate of evaporation. This process is decreased slightly when more water vapor goes to the air which also lowers the air temperature.

Therefore, it is safe to assume that the water in a big container placed under constant temperature would evaporate slower than if the temperature is rising or variable. There are several factors that affect evaporation but in reality, only a few major factors will work together to effect the process of evaporation. For example in a field of crops, the soil moisture in the soil will not evaporate quickly even if it is under the heat of the sun if there are large plant canopies that obstruct the process of evaporation.

The process of evaporation is clearly described in equations involving chemical kinetics. It is a competition between the evaporation process whereby water molecules present in the water moves to the liquid phase or what we call the process of condensation. At any kind of temperature, evaporation is proportional to water concentration in the liquid phase if there is an amount of water involved. However, this condition is altered when there is something that is dissolved in water like salt.

Fun Facts air, clothes, clothes dry faster, evaporation, process, water

Supposing You failed in Your Exam, Could You Blast a Container of Gasoline by Tossing a Lighted Cigarette?

April 24th, 2009

We usually see in movies a character tossing a lighted cigarette in a drum of gasoline and it explodes, do you believe in this?

To come up with a conclusion, an experiment has been conducted to know exactly if what is commonly shown in films is true or not. A lighted cigarette was tossed into the drum of gasoline and there was no blasting; the light of the cigarette was put off. Some people have cited experiences where they attempted to do the same experiment and found out that the lighted cigarettes didn’t get enough heat.

That is because there was no air in the drum to ignite the gasoline with a lighted cigarette. But if you fill the container with pure oxygen from a portable tank, pour a few drops of gasoline in it, then throw a lighted cigarette into the open container, gasoline will certainly blast off (but don’t you ever try it).

Another way to blast the gasoline is by puffing a cigarette close to the gasoline tank. This would mix the gasoline vapor with air which is enough to form a mixture than will ignite. Puffing of cigarette can ignite even a large amount of gasoline in an enclosed can, but tossing a lighted cigarette into an open container of gasoline will not cause even a small fire.

However, if you put up a slight heating outside the container at around 1.4 up to 7.6% gasoline vapor, that would result to an ignition. Outside these limits, gasoline cannot be ignited. If you want to try another experiment concerning this subject which is not really hazardous, puff a cigarette and place it over the opening of a pipe connected to a cooking pan with only a half liter of gasoline in it. It is certain that the explosion would be deafening.

This is because at some level above the pan, the tip’s temperature will substantially increase creating a mixture of vapor and air together. Therefore, puffing a cigarette over the pan at various levels above the gasoline will make an ignitable mixture.

If you make simple equipment which can generate oxygen that would pass through the cigarette and place it in the middle of a concrete slab, it is pretty sure that the air and vapor of the gasoline will mix together creating an explosive fire. There are cases, however, that even if you smoke a cigarette at various levels above the gasoline with an ignitable mixture, it is surprising that the gasoline will not cause ignition.

If you try to light some gasoline-soaked paper towels, and toss in more lighted cigarettes in it that will not burn the paper towels because there is no air to cause ignition.

Therefore, given the right atmosphere and elements, cigarettes can ignite gasoline; but tossing a lighted cigarette into a container of gasoline as shown in many films is not a possible way of doing it. However, this subject is being discussed only to ferret out the truth in film showing and does not intend to agitate an actual trial.

Fun Stuff air, blast, cigarette, gasoline, light, lighted cigarette