Key Concepts

Condensation is the process in which molecules of a gas sluggish down, come together, and kind a liquid.When gas molecules transport their power to other cooler, they sluggish down and also their attractions reason them come bond to come to be a liquid. Make water vapor cooler increases the price of condensation. Raising the concentration that water vapor in the air increases the rate of condensation.

You are watching: The process of steam condensing to form liquid water is


Students investigate the condensation the water vapor ~ above the inside of a plastic cup. Then they design an experiment to watch if cooling water vapor even more affects the rate of condensation. Students additionally relate evaporation and also condensation come the water cycle.


Students will have the ability to describe on the molecular level just how cooling water vapor causes condensation. College student will likewise describe the duties evaporation and also condensation play in the water cycle.


Download the student task sheet, and also distribute one every student once specified in the activity. The task sheet will certainly serve together the “Evaluate” component of every 5-E lesson plan.


Make sure you and your student wear correctly fitting goggles.

Materials because that Each Group

1 short wide-rimmed clear plastic cup1 high smaller-rimmed clear plastic cupHot water (about 50 °C)Magnifier

Materials for the Demonstration

2 clear plastic cupsRoom-temperature waterIce cubesGallon-size zip-closing plastic bag

About this Lesson

Try the demonstration prior to presenting that to her students since it will not work if the humidity is too low. You can instead show students the video clip Condensation top top a Cold Cup. The task for the college student will occupational no matter exactly how dry or humid the air.


Prepare because that the demonstration around 5–10 minutes before class.

Materials because that the demonstration

2 clean plastic cupsRoom-temperature waterIce cubesGallon-size zip-closing plastic bag


Place water and ice cubes right into two the same plastic cups.

Immediately location one the the cup in a zip-closing plastic bag and get as lot air out of the bag together possible. Nearby the bag securely.

Allow the cup to sit undisturbed for about 5–10 minutes.

Expected results

The cup within the bag should have actually very little moisture top top it because not lot water vapor from the air to be able to call it. The cup exposed come air have to have much more moisture top top the outside due to the fact that it was exposed to the water vapor in the air, i beg your pardon condensed ~ above the outside of the cup.

Show student the two cold cups of water and also ask why water appears on the exterior of only among them.

Show student the 2 cups friend prepared and also ask:

Which cup has the many moisture ~ above the exterior of it?Students must realize the the cup exposed to much more air has actually the many moisture on the exterior of it.Why execute you think the cup that is exposed to more air has an ext water on the external of it?Make certain students know that this moisture came from water vapor in the air the condensed top top the outside of the cup. Repeat students that water vapor is among the gases that provides up air. The cup in the bag has actually very small to no humidity on it due to the fact that it is exposed to much much less air. Much less air way less water vapor. Some human being think the the moisture that appears on the exterior of a cold cup is water that has leaked through the cup. Exactly how does this demonstration prove the this idea is no true?Because there is little to no humidity on the external of the cup in the bag, students should conclude that water can not have actually leaked with the cup. If the moisture came from leaking, there would certainly be water ~ above the external of both cups.Explore

Have students collect a sample of water vapor and observe the process of condensation.

Question to investigate

What happens once water vapor condenses?

Materials for each group

1 brief wide-rimmed clear plastic cup1 high smaller-rimmed clear plastic cupHot water (about 50 °C)Magnifier


Fill a broad clear plastic cup around ⅔ complete of warm tap water. Location the tall cup upside down inside the pickled in salt of the bottom cup together shown.

watch the cups for 1–2 minutes. Use a magnifier to look in ~ the sides and also top the the height cup. Take it the optimal cup off and also feel the within surface.

Expected results

The height cup will come to be cloudy-looking as tiny drops of liquid water collect on the inside surface of the cup.

Discuss with students what they think is happening within the cups.

Ask students:

What execute you think is on the inside of the optimal cup? Students must agree the the inside of the peak cup is coated v tiny fall of liquid water.How carry out you think the fall of water top top the within of the optimal cup got there?Students have to realize that few of the water in the cup evaporated, filling the within of the top cup through invisible water vapor. Few of this water vapor condensed into tiny drops of liquid water when it condensed top top the inside of the top cup.

Explain that water vapor leaves the warm water and fills the space above, contacting the inside surface ar of the peak cup. Power is transferred from the water vapor come the cup, i beg your pardon cools the water vapor. As soon as the water vapor cools enough, the attractions between the molecules lug them together. This reasons the water vapor to readjust state and also become tiny drops of fluid water. The procedure of transforming from a gas to a fluid is referred to as condensation.

Discuss exactly how to design an experiment to discover out whether boosted cooling the the water vapor influence the price of condensation.

The score of this conversation is to assist students far better understand the experimental architecture outlined in the procedure.

Ask students:

How can we set up one experiment to check out if make water vapor even colder affects the price of condensation?

How deserve to we gain the water vapor we need for this experiment?Students may imply collecting water vapor together in the previous activity or collecting it end a pot of cook water or some other way.Will us need an ext than one sample that water vapor? must we cool one sample that water vapor, but not the other?Help students know that lock will require 2 samples of water vapor, only one of which is cooled.How will certainly we cool the water vapor?Students may have many concepts for cooling water vapor, choose placing a sample in a frozen fridge or cooler filled with ice, or place a sample of water vapor outside if the weather is cool enough.How will you recognize which sample the water vapor condensed faster?By compare the size of the drops of water developed in both samples, students can determine even if it is cooling water vapor boosts the price of condensation.

Have students carry out an task to discover out whether cooling water vapor rises the price of condensation.

Read more about evaporation and condensation in the teacher lift section.

Question to investigate

Does making water vapor chillier increase the price of condensation?

Materials because that each group

2 short wide-rimmed clear plastic cups2 tall smaller-rimmed clean plastic cupsHot water (about 50 °C)MagnifierIce


Fill two large clear plastic cups about ⅔ full of hot tap water.Quickly place the taller cups upside down inside the rim of each cup that water, together shown.

Place a piece of ice on height of among the cups.

Wait 2–3 minutes.Remove the ice and use a paper towel to dry the peak of the cup wherein the ice may have melted a bit.Use a magnifier to study the top of the 2 upper cups.

Expected results

There will be bigger autumn of water top top the within of the height cup below the ice.

While wait for results, have students guess whether increased cooling will boost the rate of condensation.

Ask college student to do a prediction:

What effect do girlfriend think including the ice cube will have actually on the rate of condensation?Explain ~ above the molecule level, why friend think extra cooling might impact the price of condensation.

Discuss students’ observations and also draw conclusions.

Ask students:

Which peak cup shows up to have more water top top it?The cup through the ice.Why perform you think the cup through the ice has bigger fall of water ~ above the inside than the cup there is no ice?When the water vapor is cooled by the ice, the water molecules slow down an ext than in the cup without the ice. This allows their attractions to bring an ext molecules together to come to be liquid water.Does cooling water vapor increase the rate of condensation?Yes.What evidence do you have from the task to support your answer?Students need to realize that the bigger autumn of water ~ above the top cup through the ice show a higher amount of condensation. Because the water vapor in both to adjust of cups was condensing for the same size of time, the water vapor in the cup through the bigger autumn must have condensed at a faster rate.

Have students architecture an activity to view why wind helps points dry much more quickly.

Explain to students that as soon as water evaporates native something prefer a record towel, the area in the waiting immediately over the paper towel has a tiny extra water vapor in the from the evaporating water. Several of this water vapor condenses back onto the file so the document doesn”t dry as quickly. If the water vapor is blown away by relocating air prefer wind, there will be less condensation and the record will dry an ext quickly.

Ask students:

How would certainly you design an experiment that deserve to test whether a document towel dries an ext quickly if the air around the file towel is moving?

As you hear to suggestions from students, be certain that castle identify and also control variables. The paper should it is in in the same instance except for air relocating over one piece however not the other. That is no a great idea to punch on one since the breath can be a different temperature than the neighboring air and also contains water vapor. These are both variables the would impact the experiment. That is better to wave among the file towels back and forth for a few minutes and also have who else hold the various other or tape it so it hangs freely.


2 pieces of brown document towelWaterDropper


Place one drop of water on two pieces of brown record towel.Have your partner hold one while document while girlfriend swing the various other one through the air.After about 30 seconds compare the record towels to view if you have the right to see any kind of difference in just how wet or dried the records are.Repeat action 3 until you notification a difference between the wet clues on the paper towel.

Expected results

The water top top the paper towel with an ext air moving over it must dry faster than the other document towel top top the table. The file towel ~ above the table had actually air v a little much more humidity end it condensing back onto the paper. This slowed down the dry process. The document waved in the air didn’t have actually humid air around it and condensing back on the as lot so it dried much more quickly.

Extra Extend

Use the procedures of evaporation and also condensation to purify water.

Evaporation and also condensation have the right to be supplied to purify water. Imagine what might happen if fancy water evaporates and also then condenses.

Question come investigate

If fancy water evaporates and also condenses, will there be any kind of color in the water the is produced?

Materials for each group

1 short wide-rimmed clean plastic cup1 tall smaller-rimmed clean plastic cupHot waterFood coloringIce cubeWhite napkin or record towel


Add hot tap water to a wide clear plastic cup until it is around ⅔ full.Add 1 drop of food coloring and also stir until the water is totally colored.

Turn an additional clear plastic cup upside under on the cup of hot water as shown. Location an ice cream cube on the height cup to make condensation take place faster.

See more: How Much Do Aluminum Rims Weigh ? How Much Does Stock 17 Aluminum Wheel Weigh

Wait 1–3 minutes because that water vapor to condensation to liquid water top top the inside surface ar of the peak cup. Usage a white document towel come wipe the within of the cup to check for any type of color.

Expected results

The water that collects top top the inside of the height cup will be colorless. The color will remain in the bottom cup.

Explain that the procedure described in the procedure is referred to as distillation. Throughout distillation, water that has actually substances liquified in it can be purified (as lengthy as these substances don’t conveniently evaporate). Once the water evaporates and also condenses, the food color is left behind and also the pure water deserve to be collected and used.