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Online reading assignment question: condensation

Astronomy 210, Fall Semester 2009
Cuesta College, San Luis Obispo, CA

Students have a weekly online reading assignment (hosted by SurveyMonkey.com), where they answer questions based on reading their textbook, material covered in previous lectures, opinion questions, and/or asking (anonymous) questions or making (anonymous) comments. Full credit is given for completing the online reading assignment before next week's lecture, regardless if whether their answers are correct/incorrect. Selected results/questions/comments are addressed by the instructor at the start of the following lecture.

(The following question was asked prior to the lecture on planetary formation processes and the solar nebula hypothesis.)

The outside of a cold beverage container will eventually develop "condensation" (small drops). Briefly explain where these drops came from. (Graded for completion.)

The following are all of the student responses to this question, verbatim and unedited.
"the temp of the drink on the inside and the temp of the outside are different. if the outside is warmer you get the drops"

"the moisture in the air"

"they are from the outside being hotter than the inside of the can"

"the outside air around a cold cup causes the water drops"

"rapid change in temperature"

"yep"

"The air has moisture so when they meet the container, the two molecules stick"

"the water in air sticks to the glass"

"These drops are created when warm air in the atmosphere comes into contact with the cool surface of the container. The vapor in the air condenses on the outside of the container."

"air molecules stick to the container"

"The air hits the glass which is cold and forms into water droplets"

"beverage is getting warmer causing some frost on the outside to melt"

"con-den-sation sation sation..."

"i have no idea"

"frost melting"

"These drops came from the water in the air that gathered and stuck to the wet surface."

"The temperature of the beverage is less than that in the atmosphere and will try to reach equilibrium with the atmospheric temperature. These water droplets develop by the water vapor in the air changing into liquid air by this thermodynamic reaction."

"because the drink is cooling down so its making it dense"

"These drops come from the air around the object that the drops have formed on. The energy in the material in the air around the object is absorbed into the object, slowing the movement of the materials, and allowing the materials to 'fall towards' the object. This builds a layer of material that eventually forms a pool of like materials."

"it cools its self off from the inside out"

"The rain."

"Condensation occurs when a liquid, cool object is heated by it's surrounding atmosphere. The drops are the product of this occurrence."

"atoms ran into the cold glass and stopped, more atoms ran into those atoms and clumped together to form molecules which stick together to from droplets"

"Water vapor in air immediately next to the cold surface cools, allowing droplets to form."

"does it come from tiny tiny holes in the container??"

"These drops come from humidity coming from the air which lands on a cool surface such as the beverage container."

"the water molecues cooling down on the outside of the cold beverage creating the condensation"

"the molecules in the air hit the cooler surface of the glass and stick there"

"when it adds matter one atom or molecule at a time from a surounding gas"

"they came from the particles sticking to the cold can"

"I don't know."

"the cold can collected the moisture in the air..."

"Water vapor condenses into liquid after making contact with the surface of a cold container surface."

"Water molecules."

"the condensation comes from excess humidity from the outside air. The glass only provides a cold surface on which humidity can visibly condense. When the warm, moist air comes into contact with the cooler glass surfaces, the moisture condenses."

"Osmosis happens."

"the coldness from the beverage meeting room temperature"

"MMMM...not sure is it the Volatile substance?"

"the inside"

"Condensation occurs when vapor is cooled to its dew point."

"These drops come from moisture in the air that is warmer than the cold beverage and in direct contact these molecules slow down creating moisture on the surface, Heat Exchange."

"The drink inside"

"somethin to do with it the temperature surrounding the beverage....i'm not sure"

"They came from the atmosphere. Water vapor in the atmosphere comes in contact with the cold surface of the container and condenses into liquid water."

"the inside"

"These drops came from the air."

"because the inside of the cup is colder than the out"

"i dont know"

"Osmosis"

"they came from the can itself."

"Condensation usually occurs when a parcel of rising air expands and cools. If it cools enough, some of the water vapor molecules clump together faster than they are torn apart from their thermal energy."

"Warm moist air carries invisible molecules of water. When air gets colder it compresses (and if air gets hotter it expands, its volume increases). As the air cools, at a certain point the water molecules are unable to stay in the air as invisible 'gas' (water vapour), and they change their state from gas to liquid. 'Liquid' is a more condensed form than a gas. The molecules are closer together in liquids than they are in their gas form/state. If warm moist air meets the side of an icy glass, the water vapour in that bit of air 'condenses' into a liquid (water) on the side of the glass. answer provided by ask.com"

"its the temperature of the substance that is inside"

"water vapor in the air cools down and reverts to it's liquid state on the beverage."

".....jesus?.....hahaha"

"the hot air around the container cooling"

"the warm air on the outside turns to liquid as it's cooled by the surface of the can....or something like that.."

"the small drops come from the cold beverage; as the beverage sits out in room tempeature longer its composition breaks down in is released in drops"

"it comes from the cold beverage warming up"

"Water vapor is condensing into liquid when making contact with a cold surface."

"When water vapor in the air meets something cold its molecules clump together to form droplets."

"the drops came from the water being cold enough to emit out side of the cup"

"The cold substance on the drink begins to melt, causing drops."

"The beverage starts out with cold water molecules in the inside. As the molecules cool down, they begin to move about more slowly and draw closer together. If they are cooled down enough, they begin to stick together"

"comes from the vapor created by the contrast between the the temperature of the air and the temperature of the beverage... maybe..."

"Moisture sucked out of the air"

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