Cloud Formation – Cloud in a Bottle Demonstration: plastic bottle + bike pump version
- Activity 1: Cloud in a Bottle
- Target grades: 1st-6th
- Teaching objective/expected knowledge outcome: Students will be able to recognize different ingredients required for cloud droplet formation.
- Instructions on how to conduct an activity
- Materials:
- 2 Liter plastic bottle
- ~ ¼ cup of water
- Hairspray
- Bike tire pump that will fit into the opening of the plastic bottle
- Directions:
- 1. Empty and clean the plastic bottle, removing the label so that the bottle is see-through
- 2. Pour about ¼ of a cup of water into the bottle (just enough to cover the bottom)
- 3. Attach the bike pump valve stem to the opening of the bottle
- 4. Use the pump to increase pressure in the bottle (approx. 20-40 pumps, or until you can feel the pressure increase)
- 5. Release the valve stem from the bottle opening. Following these 5 steps will not form a cloud in the bottle. Here, ask what ingredient students think might be missing, and why a cloud has not formed.
- 6. Repeat steps 1-5, with the additional step of spraying a small amount of hairspray in the bottle after step 2. The hairspray will serve as the cloud condensation nuclei. After step 5 is completed, a cloud should form inside the bottle now that we have all ingredients for cloud droplet formation!
- Supplemental material
- How to assess knowledge learned
- Ask students what they learned
- Background information
- Clouds form when water vapor condenses into droplets. This requires a saturated environment (the relative humidity is 100%). Adding pressure warms the air, allowing water in the bottle to evaporate, increasing the humidity. Letting the pressure out cools the bottle, which raises the relative humidity. But clouds also requires particles for water vapor to condense on. These particles, known as cloud condensation nuclei, can be dust, sea spray, pollution, or bacteria. In this experiment, the hairspray serves as the cloud condensation nuclei.
