Bergeron M&M's

Tuesday 1:30pm-2:40pm
Share-a-thon Part of Tuesday


Alicia Mullens, De Anza College


For the share-a-thon, I'll demonstrate the "rules" of the game, and walk people through how/why to do it. I'll provide m&m's (and skittle for those who don't like chocolate) and game boards along with a rule card for them to take home with them.


After explaining the concepts of Vapor Pressure and Saturation Vapor Pressure to my students, I use an "activity board" to represent a cloud along with M&M's to represent water vapor molecules to model how the Bergeron process (the process of growing ice crystals at the expense of supercooled water droplets) occurs.

After completing the exercise, students should be able to:
1. Discern a saturated environment from a super-saturated and un-saturated environment.
2. Determine what happens to ice crystals and supercooled water droplets in a cloud, and why.
3. Have a better appreciation for precipitation processes, and why the formation of ice crystals is fundamental for rainfall in the mid and upper-latitudes.


The activity allows for students to both revisit previously discussed humidity concepts (saturation, vapor pressure, cloud types) while applying them to a new problem (how do ice crystals grow in a cloud). This activity is used in hybrid and/or partially-flipped classes where students first get a "lesson" on what the bergeron process is, and then use m&m's to model it.

The target audience is General Education Students and Introductory-level Majors in Meteorology.

Why It Works

The activity helps students to visualize how the Bergeron process works by moving water vapor molecules (m&m's) around between a super-cooled droplet and ice crystal. The Bergeron process tends to be one of the more "over their heads" concepts, and so having a simple, hands on activity to model how it works helps them experience it... it brings it off the paper and into their hands.