❄❅❆Snowflakes ❆❅❄

<chirp, chirp> “Moire here.”

“Uncle Sy! Uncle Sy! It’s snowing again!”

“Yes, Teena, I noticed. I’ll be over to help you build a snowman in a little while.”

“Yay! There’s so much snow coming down. I bet there’s a kazillion snowflakes!”

“Maybe even more. And no two of them are exactly alike.”

“Yeah, that’s what Mommy said. I went outside a while ago and caught a bunch on my coat sleeve like you showed me. All different shapes — stars and pencils and almost-round ones and spiky balls. I can’t remember them all. How do we know that they never match? Did someone look at them with a computer camera?”

“Whoa, that’s too big a job for even a really fast computer with a really good camera. No, it goes back to how snowflakes grow up.”

“Ha-ha, that’s funny! Little baby snowflake grows up to be a big Mommy snowflake!”

“Well, in a way that’s what happens. You know clouds are really made of teeny water droplets, right?”

“Yeah, Mommy says it’s a fog, but way up in the air. But the fluffy ones are pretty.”

“Yes they are, but inside some of the not-fluffy clouds it can be very cold and windy.”

“Danger cold?”

“Very danger cold. Cold enough for some of those teeny droplets to freeze and become ice droplets. When an ice droplet touches a water droplet they merge to make a bigger piece of ice. The winds blow the ice up and down between wet places and cold places inside the cloud over and over again. The piece of ice grows and grows until it gets so heavy it falls down out of the cloud.”

“Like a roller coaster! But wouldn’t that just make round ice? That’s not what I caught on my sleeve.”

“Sometimes it does. Remember that hail storm we had last year?”

“Oooo. Yeah, we got inside just in time. Those hailstones went pitter‑patter all over the sidewalk and the windows.”

“Just be very glad they were only pinkie‑nail‑sized. I was in a storm once where the hail was as bigger than your shooter marble. It made dents on my car.”

“WOW! That would hurt!”

“It certainly would. I hope you’re never in one of those ice storms, just stars‑and‑pencils snow like you saw on your sleeve. Stars‑and‑pencils happens when the winds inside the cloud are gentler and give the teeny ice droplets time to grow a different way.”

“Different how?”

“Want to do an experiment?”

“Over the phone?”

“Sure. Get your bag of marbles and a lid from one of your board game boxes. Say when you’re ready.”

“OK … ready!”

“OK, Put the lid on the floor face‑down but prop it up so one corner is lower than the other three.”

“Umm … ready!”

“Now slowly pour your marbles into the lid so they lie together in one layer. Slowly, we don’t want them going all over the floor.”

“That’d make Mommy mad. Ooo, pretty! They make a honeycomb pattern. I see a lot of hexa–, um…”

“Hexagons. Good girl, you did that just right. That pattern is a lot like how water molecules arrange themselves when they freeze. When a new molecule walks up to some ice, it tries to touch as many other molecules as it can. That automatically makes hexagons.”

“Oh! Teeny hexagons grow up to be snow hexagons! Ha-ha!!”

“Mm-hm, and depending on conditions some rows grow fast to make flat plate snowflakes or a different set of rows might grow quickly to make frilly stars.”

“But why don’t they all grow the same?”

“Because of how messy it is inside that cloud. Winds blowing up and down and sideways, wet places and not‑so‑wet places scattered all over everywhere. Two baby snowflakes starting right next to each other can wind up on opposite sides of the cloud with entirely different stories to tell.”

“But then how can different sides of the same snowflake be the same?”

“They’re on the same flake so they’re always close together as the flake grows. They don’t get a chance for different stories. OK, I just finished up. It’s snowman time.”

“Yay!”

Nope, ain’t gonna happen. Not with water, not with anything else.

~~ Rich Olcott

The Sight And Sound of Snow

<ring> “Moire here.”

“Uncle Sy! Uncle Sy! It’s snowing! It’s snowing!”

“Yes, Teena, it started last night after you went to bed. But it’s real early now and I haven’t had breakfast yet. I’ll be over there in a little while and we can do snow stuff.”

“Yaaay! I’ll have breakfast, too. Mommie, can we have oatmeal with raisins?” <click>


<knock, knock> “Uncle Sy! You’re here! I wanna go sledding! Get my sled out, please?”

“G’morning, Sis. G’morning, Teena. Get your snowsuit and boots on, Sweetie. Want to come along, Sis? It’s a cold, dry snow, not much wind.”

“No, I’ll just stay warm and get the hot chocolate ready.”

“Bless you for that, Sis. OK, young’un, ready to go?”

“Ready! Pull me on the sled to the sledding hill, Uncle Sy!”


“Ooo, it’s so quiet. Why’s it always quiet when snow’s falling, Uncle Sy? Is the world holding its breath? And why is snow white? When I hold snow in my hand it melts and then it’s no-color.”

“Always the good questions. Actually, these two are related and they both have to do with the shape of snowflakes. Here, hold out your arm and let’s see if you can catch a few. No, don’t try to chase them, the breeze from your arm will blow them away. Just let them fall onto your arm. That’s right. Now look at them real close.”

“They’re all spiky, not flat and pretty like the ones in my picture book!”

“That’s because they grew fast in a really cold cloud and didn’t have time to develop evenly. You have to work slow to make something that’s really pretty.”

“But if they’re spiky like this they can’t lay down flat together and be cozy!”

“Ah, that’s the key. Fresh spiky snowflakes make fluffy snow, which is why skiers love it. See how the flakes puff into the air when I scuff my boot? Those tiny spikes break off easily and make it easy for a ski to glide over the surface. Your sled, too — you’ve grown so big I’d be hard-put to pull you over wet snow. That fluffiness is why <hushed voice> it’s so quiet now.”

“Shhh … <whispered> yeah … <back to full voice> Wait, how does fluffy make quiet?”

“Because sound waves … Have we talked about sound waves? I guess we haven’t. OK, clap your hands once.”

<CLAP!>

“Good. When your hands came together they pushed away the air molecules that were between them. Those molecules pushed on the next molecules and those pushed on the next ones on and on until they got to your ear and you heard the sound. Make sense?”

“Ye-aa-uh. Is the push-push-push the wave?”

“Exactly. OK, now imagine that a wave hits a wall or some packed-down icy snow. What will happen?”

“It’ll bounce off like my paddle-ball toy!”

“Smart girl. Now imagine that a wave hits fluffy snow.”

“Um … it’ll get all lost bouncing between all the spikes, right?”

“Perfect. That’s exactly what happens. Some of the wave is scattered by falling snowflakes and much of what’s left spreads into the snow on the ground. That doesn’t leave much sound energy for us to hear.”

“You said that snow’s white because of what snow does to sound, but look, it’s so bright I have to squint my eyes!”

“That’s not exactly what I said, I said they’re related. Hmm… ah! You know that ornament your Mommie has hanging in the kitchen window?”

“The fairy holding the glass jewel? Yeah, when the sunlight hits it there’s rainbows all over the room! I love that!”

A beam or white light passing through two prisms.  The first produces a spectrum and the second remixes the colors to white.

“I do, too. White light like sunlight has all colors in it and that jewel splits the colors apart so you can see them. Well, suppose that jewel is surrounded by other jewels that can put the colors together again. Here’s a picture on my cellphone for a clue.”

“White goes to rainbow and back to white again … I’ll bet the snowflakes act like little jewels and bounce all the colors around but the light doesn’t get trapped and it comes out and we see the WHITE again! Right?”

“So right that we’re going home for hot chocolate.”

“Yaaay!”

~~ Rich Olcott

PS – A Deeper Look.