Cloud in a Bottle

Water Vapor in the Atmosphere

(Based on an activity by Kathleen Koziel, Science and Children, "The Water Cycler," Sept. 1994 )

2 Liter bottle

Plastic wrap

Ice cubes

Rubber band

Warm water

Ziploc ® bag

Scissors

Procedure:

Cut the top off the 2 liter bottle.
Pour hot water into the bottle to a depth of approximately 6 cm. The water should be about 50 degrees Celsius.
Cover the top of the bottle with plastic wrap. Secure the plastic with a rubber band.
Place 5-10 large ice cubes in the Ziploc ® bag and seal the opening.
Place the bag of ice cubes on the plastic wrap sealing the top of the bottle.

Observations:: Observe the bottle for a few minutes then record your observations in the space below.; As the warm moist air evaporates and rises it will meet the cold air from the ice at the top. This should result in a small cloud at the top of the container but careful observation may be needed to see it. Water vapor will condense on the bottom of the plastic wrap. Droplets will form and begin to drip back down into the container.

Conclusion:: Did your observations support your hypothesis? Defend your answer.; Answers may vary but should relate to moisture in the air condensing on the plastic. Students should deduce that water vapor was added to the air from the hot water. Support for this is that it condensed on the cold plastic as water droplets.
Follow up:: On a separate page name one variable in this experiment that you could investigate in a follow up experiment. Describe how you would design this experiment.; Suitable variables for investigation include: the amount and temperature of the water, the number of ice cubes, and the type of container used. Allow the students to try their experiments. The assessment rubric is used to grade only the follow up experiment.

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