Today, in honor of the weather, we delved into rain and the water cycle.

We began by discussing wind and air. I told them there was, at that moment, a low pressure system over Chicago. We made silly faces for low pressure (sucking in our cheeks) and high pressure (puffing our cheeks out), and talked about what would happen if we put a straw in our mouths: would air be pushed out, or get sucked in?

Next came a demonstration about why air would move up or down… I was hoping to echo Kyle’s lesson from a couple weeks back, and sure enough, they all seemed to know exactly where I was going! Which is good, because the experiment itself (blue cold water, red hot water, keep separated by a card, then remove the card) was not a smashing success… Instead of two distinct layers, the consensus was “It’s all kind of purplish.” 😅

Regardless, we got to talk about how low pressure pulls warm, moist air upward, where it cools and lets go of its water. And that brought us to the water cycle: evaporation, condensation, precipitation, collection.

To demonstrate the water cycle, we built little miniature terrariums. (Terraria?) I gave them small plastic mason jars with screw-top lids, and we began by adding a layer of lava rock. This layer was for collection, I told them. It’s where the water will gather. Next some activated charcoal (which filters the water), and finally some soil. I was hoping there’d be a break in the rain and we could collect some moss, but no dice, so a few of us ventured out to a nearby tree to collect a bit of lichen for everyone. Finally I spritzed some water in and we screwed them up tight.

The idea is for them to watch their terrariums for signs of a daily water cycle: it should warm up in the morning, water should be pulled upward and condense on the plastic, then it should fall back down and collect at the bottom when things cool off. They seemed, however, much more intent on poking holes in the lids so they could put tarantulas inside. (Tarantulae?)

Many thanks to Kathy, Brigit, and Darla for all your help today!

Weekly Summary: Rain and the Water Cycle – Quarks – Nature Study