Chief Meteorologist Michael Stevens demonstrated a STEM experiment in Traverse City to show how rain forms using a mason jar and ice cubes. The demonstration illustrates the atmospheric processes of condensation and precipitation.
The experiment, which focuses on science, technology, engineering and math, provides a visual representation of the water cycle. Because the process requires heating water on a stove to near-boiling temperatures, Stevens said an adult should be present to supervise the activity at home or in the classroom.
The experiment requires a specific set of materials including a pot, a stove, water and a clear mason jar. Participants also need a glass of ice cubes and a bowl or similar cover to place on top of the jar.
To begin the demonstration, water is heated in a pot and poured into the mason jar until it is about one-third full. Stevens said the water should reach a depth of approximately two to three inches in the bottom of the jar. The jar is then covered with the bowl to prevent evaporated water from escaping.
After one or two minutes, ice cubes are added to the bowl on top of the jar. The cold surface of the bowl causes the water vapor to condense on the underside. These droplets eventually form and fall back into the jar as simulated rain.
The condensation and dripping inside the jar represents the natural process of warm air rising and cooling in the atmosphere. As moisture condenses, it becomes heavy enough to fall to the ground as precipitation.
Stevens noted that the experiment differs from real-world rainfall because it does not include moisture condensing around small particles. While raindrops in the atmosphere typically form around these nuclei, this demonstration relies on water collecting on the bowl until it is heavy enough to fall.