Cloud in a Bottle and the Scientific Method

Lesson Plan

Science/Math Standards Addressed (From the Colorado Department of Education)

Science

Standard 3 – Earth Systems Science

  • Third Grade: Outcome 1 –Evaluate evidence that Earth's geosphere, atmosphere, hydrosphere, and biosphere interact as a complex system
  • Fourth Grade: Outcome 1 –Apply an understanding that energy exists in various forms, and its transformation and conservation occur in processes that are predictable and measurable
  • Fifth Grade: Outcome 2 – Evaluate evidence that Earth's geosphere, atmosphere, hydrosphere, and biosphere interact as a complex system

Objective:Using a bike pump and clear liter bottles containing small amounts of various liquids, students explore the nature of cloud formation using the scientific method.

Materials

  • 1 Bike pump with a rubber stopper roughly the diameter of a soda liter bottle top attached to the end (to be shared amongst all groups)
  • 1 clear liter bottle for each group of students
  • A few tablespoons of a variety of liquids:
  • Water
  • Isopropyl alcohol (aka rubbing alcohol)
  • Soda*
  • Body splash*
  • Vinegar*
  • Glass Cleaner*

*optional and can be substituted with some other form of liquid

Before Students Arrive: Fill each empty liter bottle with a few tablespoons of each liquid and clearly label each bottles contents.

Procedure:

  1. Lead a discussion about clouds. Ask students what clouds are made of. What form of matter are clouds? How are clouds formed? Students might guess that clouds are a form of gas. Explain to students that water exists in the air as a gas and we call it water vapor. But clouds actually form when this water vapor sticks together and turns back into liquid water droplets (condensation).
  2. Explain that if there is water vapor in the bottle we can make it condense. First we pump air into the bottle to “squeeze” the vapor together. When we release the stopper the air in the bottle will cool, allowing the water molecules to stick together and form a cloud.
  3. Demonstrate the process by pumping air into the bottle containing water, about 8 pumps, and releasing. A wispy cloud should form.
  4. Now that students have some idea that we need to make the vapor condense in order to make a cloud, have them discuss whether or not we could make clouds out of the other liquids. Provide leading questions such as: Will these other liquids produce as much vapor in their bottle. Will the vapor be more difficult to stick together? Have students form hypotheses about which liquids will form clouds/which will form the best clouds.
  5. After having formed their hypotheses allow each group to pick one liquid to test.
  6. Have each group come to the front of the class one by one and test to see if they can make a cloud in their bottle. Discuss the results after each group. Create a table to document their observations. Rank which liquids formed the most visible clouds and which ones did not.
  7. After testing each liquid have students discuss why they think certain liquids preformed better than others. (The alcohol based liquids should create notably more visible clouds than the others.)
  8. To end the activity, explain how alcohol evaporates more quickly than water (the alcohol molecules have weaker bonds than the water molecules, so they escape into the air more readily). What effect might this have on making clouds? (There is more alcohol vapor in the bottle, thus more molecules to condense!) Why aren’t clouds on Earth made of alcohol then! (Explain that about 70% of the Earth’s surface is water). Explain that Jupiter actually has clouds made out of ammonia!

Possible Extensions:After learning that clouds on Jupiter are made out of ammonia, students may wish to research the different types of clouds on other planets and moons!