Up to 32 students
There are many things that help in cloud formation, humidity, air pressure and temperature. As air cools due to expansion of the rising air mass, water vapor begins to condense on condensation nuclei such as dust, ice and salt. This process forms clouds. Sometimes an elevated portion of a frontal-zone forcing broad areas of lift, which form cloud decks such as altostratus or cirrostratus. Stratus is a large dark low cloud deck that tends to form when a stable cool air mass is trapped underneath a warm air mass (front). It can also form due to the lifting of fog during breezy conditions. Clouds can also be formed due to lifting over mountains and other topography.
The purpose of the experiment is to demonstrate the role temperature plays in cloud formation. A sample atmosphere is created using a plastic bottle filled with water. By squeezing the bottle, you can change the temperature of the air inside. When the air temperature is decreased, a cloud is created inside the bottle.
- Students will tie together ideas behind evaporation, condensation and precipitation.
- Students will be introduced to different types of clouds. (worksheet)
Large clear plastic bottle per group
graduated cylinder or measuring cup
Cold and hot water
Activity 1: Growing the L.I.N.K.
Direct students to add to their concept maps with information that was covered in the last class; ask students to also add information about what the inner and outer planets are made out of if this has not already been brought up on the concept maps. 3-minutes.
Following the 3-minute activity ask students to look around at other groups concept maps and inquire about vocabulary or concepts they may be unfamiliar. Maps may either be taken down and students prompted to write down what they may have just learned about the topic discussed or maps may be left up for duration of unit to be built upon at a later time in substitution for a word wall.
Activity 2: Cloud Case
Print out directions for students, guide them to read all the directions before beginning the experiment.
#1: Pour 100mL or 1/3 cup of cold tap water into a clear plastic bottle and place cap on it. Shake the bottle for 30 seconds and then set it on your table.
#2: Squeeze the bottle and then release the pressure. Repeat this process several times.
In this step you are saturating the atmosphere inside the bottle. By squeezing the bottle, you increase the air pressure inside the bottle, which increases the air temperature. With the air heated, more water moves into the air, saturating it. When you release the pressure on the bottle, you decrease the air pressure. This lowers the air temperature and causes condensation in the bottle. These are the principles that will allow you to create a cloud in the next step.
#3: Remove the cap from the bottle and light a match. Hold the match over the mouth of the bottle. Quickly squeeze the bottle to extinguish the match; then slowly release the pressure to draw smoke into the bottle. Replace and tighten the cap. Repeat Step #2.
In this step, a cloud should have formed above the water inside the bottle. As in Step #2, squeezing the bottle forced condensation inside the bottle. Now that you have added smoke into the bottle, the water has something to condense upon. The condensed water forms the small cloud inside the bottle.
#4: Rinse the bottle thoroughly and pour 1/3 cup of hot tap water into it. Shake the bottle for 30 seconds and place it on your table.
#5: Squeeze the bottle and then release the pressure. Repeat this process several times. Then repeat Step #3, extinguishing a match over the mouth of the bottle and drawing the smoke inside. Then repeat Step #2 again, squeezing and releasing the bottle to create a cloud.
Note for Teacher:
In this step, a bigger cloud should form in the bottle. This is because of the hot water has heated the atmosphere inside the bottle, so it is able to hold more water than before. So when condensation is forced inside the bottle, more water condenses and a larger cloud forms.
Activity 3: Think, Pair, Share
Have students work with a partner or in a small group to answer the following questions:
How do clouds form?
Do clouds form easier with hot water or cold water?
What does squeezing the bottle do to the water and vapor in the bottle?
Conclusion and Wrap Up:
Have students research different types of clouds in-class or for homework
Have students add new concepts to their LINK.
New York Scope and Sequence:
Intermediate and High School Science Standards
Key Idea 1.2g, 2.2a - 2.2d, 3.1