Let it snow!




making snow flakes

Getting a closer look at snow crystals as they form inside a diffusion chamber




Today we learned firsthand about snow in our winter family program. Children and parents made snow flakes to take home, they also grew snow in home-made nucleator reactors! It took less than ten minutes for the water crystals to form, and they resembled icy plants as time progressed.

How does this all work? Inside the plastic bottle, we attached a water dampened sponge and some fishing line, then we surrounded the bottle with dry ice. Keep in mind water molecules can be dynamic! They move around very rapidly in our atmosphere as water vapor, and they don’t move much at all when they freeze. In the plastic bottle, this movement was observed as diffusion – cool molecules fall in the air and warm molecules rise. The molecules also crash into one another and clump up (they nucleate).  For our experiment, the fishing line served as the nucleation site, a place for the water particles to cling to as they moved inside the bottle. The crystals formed on the fishing line took on several unique but basic dimensions, such as dendrites and fish-bones. Just think, these are the same types of crystals that form in clouds, and once enough of these crystals accumulate, their weight breaks away and they fall to the earth’s surface – as snow.

Be sure to look to the skies this February, or you can make your own snow-machine at home.

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