Lesson 1: Weather Science & Cloud in a Jar
Category: Science—This lesson includes information on the water cycle and weather, as well as a hands-on activity where you get to create a cloud in a jar!
The Water Cycle:
The water cycle has three main phases: evaporation, condensation, and precipitation. Evaporation occurs when water on the Earth, like bodies of water, is heated by the sun. When water gets warm enough, it will evaporate into water vapor. The water vapor rises into the atmosphere, bringing us to the next stage: condensation. Condensation occurs when the evaporated water vapor is cooled in the atmosphere, and the molecules begin to stick together, or condense, and form clouds. When clouds collect enough water molecules, the water droplets in the cloud start to get too heavy for the cloud to hold them, and the droplets fall back to the ground as rain during stage three: precipitation. Other forms of precipitation besides rain include snow, hail, and sleet. Water molecules can also come from trees and plants during transpiration, and when rainwater collects back into bodies of water we call it percolation.
Cloud in a Jar Activity:
Materials Needed:
A jar with a lid
About 1/3 cup hot water
Ice
Hairspray
Instructions:
Start by pouring the hot water into the jar. Swirl it around a bit to warm up the sides of the jar.
Turn the lid upside down and place it on the top of the jar. Place several ice cubes onto the lid, and allow it to rest on the top of the jar for about 20 seconds.
Remove the lid, quickly spray a bit of hairspray into the jar, and then replace the lid with the ice still on top. Watch the cloud form.
When you see a good amount of condensation form, remove the lid and watch the “cloud” escape into the air.
What Happened?
When you add the warm water to the jar, some of that water turns to water vapor. The water vapor rises to the top of the jar, where it meets cold air thanks to the ice cubes on top. Water vapor condenses when it cools down. However, a cloud can only form if the water vapor has something to condense on to. In nature, water vapor may condense onto things like dust particles, air pollution, pollen, volcanic ash, and more. In the case of this activity, the water vapor condensed onto the hairspray.
