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Dry Ice in the Rain…

Every Friday (okay, every other Friday when I’m busy) I teach a science lesson at a local elementary school. Mostly, I try to keep my lessons fairly fun– a little science followed by some explosions, a laser, bubbles, and now and then some green goo. Today, I taught the kids a little about phase changes and sublimation. I brought in some dry ice for all of us to play with. We first dropped dry ice in water and made dramatic horror-flick fog. Nest, we inflated balloons and plastic trash bags by putting a little dry ice inside. Finally, we watched bubbles (as if dry ice wasn’t fun enough… bubbles!) float mysteriously on the carbon dioxide vapor then sink as the carbon dioxide permeated through the bubble membrane, making the bubble heavier. Some of the bubbles even froze when they reached the dry ice cubes. All very cool stuff, and I think the kids had fun.

On my way back to my MIT office, however, I became caught in a warm, spring thundershower. I was still carrying a couple of pounds of dry ice when I was caught in the downpour.

Since I’m at MIT now, let me put this in equation form:

Warm rain + dry ice cubes in a cardboard box = crazy lady carrying a foaming cauldron.

Let’s just say people looked at me awfully strangely on the street… and it’s certainly good I didn’t need to take the T anywhere.

Evelyn

Evelyn is a geologist, writer, traveler, and skeptic residing in Cape Town, South Africa with frequent trips back to the US for work. She has two adorable cats; enjoys hiking, rock climbing, and kayaking; and has a very large rock collection. You can follow her on twitter @GeoEvelyn. She also writes a geology blog called Georneys.

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5 Comments

  1. I'm surprised at MIT anyone would even notice.

    Dry ice is fun. If you push a key into it makes a high pitched whining sound. I think it's vibrations (or maybe some sort of weird resonance in the dry ice) as the gas escapes.

    If you take a very small piece and very carefully place it on a molar, and very carefully bite down (have I mentioned you have to be careful?), it'll sublimate, but your teeth hold it in, so you get little chunks of dry ice shooting out of your mouth. It's dangerous, and you shouldn't do it, but it's cool.

  2. Warm rain + dry ice cubes in a cardboard box = crazy lady carrying a foaming cauldron.

    Heh, I would have liked to catch that on my video camera – could have gone in the "Strange sitings in Boston" file. ;-)

    Sounds like fun for the kids, and the most memorable way to learn something new. It also provides fodder for fiction. I was reminded of a story my niece started in 5th grade, titled "The Fog Between Us." She makes reference to:

    I thought back to class, who creates things, who creates things? Then I got it, Kevin and Ethan they love to make things like clouds, water, and light.

    (later)

    I tiptoed around, it was a science lab. I went further. I saw Kevin and Ethan sleeping. Why would they be sleeping in a science lab? I tiptoed toward the door, I pushed it slightly opened and pushed out.

    I was in my school hallway…

    Kevin and Ethan might end up at MIT. :-))

  3. The Bad Astronomer said,

    I’m surprised at MIT anyone would even notice.

    Yeah, me too. I've walked around campus wearing a hat made from a colander and 220 red LEDs, wired up so that spirals of light spun round my head. I got second glances, but not too many thirds.

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