Nov 13: Snow Made From a Cloud and NASA Finds Water on the Moon

Host 1 Welcome to This Day in Science and Discovery for Kids on this day November 13th we're taking a deep dive into how humans learn to find and play with frozen water

Host 2 Yeah from making our own snow here on Earth to you know finding hidden treasures way out in space

Host 1 Right so let's start in 1946 with Vincent Schaefer he was this big nature lover who actually had to leave high school early to help his family out

Host 2 But he never stopped experimenting.

Host 1 Exactly. And he ended up doing something seemingly impossible. He made actual snow fall from a natural cloud over Massachusetts.

Host 2 Yeah, he pulled this off by dropping, I think it was six pounds of dry ice out of a small airplane, like right into a cloud.

Host 1 Wait, just to clarify for everyone, dry ice is frozen carbon dioxide, right?

Host 2 Right, exactly.

Host 1 Okay.

Host 2 It's much, much colder than normal ice. And this was basically our first successful try at cloud seeding.

Host 1 Okay, but hang on.

Host 2 Yeah?

Host 1 How does someone even get this idea? Because, you know, if I open my kitchen freezer and breathe into it, I just get foggy glasses. I don't get a snowstorm.

Host 2 Well, that's the best part. It started by accident. On a really hot summer day, Schaefer's lab freezer just wasn't cold enough for an experiment he was doing.

Host 1 Oh, so he added the dry ice to cool it down.

Host 2 Yes. And when he happened to breathe into that super chilled space, this bluish haze appeared and it instantly turned into millions of tiny ice crystals.

Host 1 Oh, wow. So what's the actual science there? Is it like he provided a nucleus, like a tiny starting seed for the water droplets to grab onto?

Host 2 Yeah, pretty much.

Host 1 So it's sort of like giving the cloud a recipe for snow.

Host 2 That is a great way to put it. You see, clouds are often full of super cooled water. That's water below freezing, but you know, it hasn't turned to ice yet because it lacks a starting structure.

Host 1 Right. It physically needs a speck of dust or ice to build on.

Host 2 Exactly. The dry ice rapidly cooled the air, forcing the moisture to crystallize. Once a few crystals form, water droplets stick to them, freeze and grow.

Host 1 And then they get heavy enough and gravity takes over.

Host 2 You got it. And that test thrilled the whole nation. It led to big government weather research and the snow making machines we see at almost every ski resort today.

Host 1 Okay, so let's connect Earth's frozen water to a search for ice much, much further away. Let's fast forward to 2009.

Host 2 Over the Lcross mission?

Host 1 Yes. NASA intentionally crashed a used rocket into Cabeus. That's a dark 60 mile wide crater near the moon's south pole.

Host 2 And they did this just to throw up a huge cloud of dust right?

Host 1 Exactly. And then a second spacecraft flew right through that dust cloud using spectrometers.

Host 2 Right. And for our listeners, spectrometers are basically tools that read light to see what things are made of.

Host 1 Yeah, like a molecular fingerprint scanner.

Host 2 Mm-hmm.

Host 1 And they found water. Like at least 25 gallons of it just in their view. And the scientists actually had a holy cow reaction when the data came back.

Host 2 I mean, who wouldn't?

Host 1 Right. That crater holds more water than Earth's driest desert.

Host 2 Which is just great news for future moon explorers. They're going to need water for drinking and bringing heavy water from Earth is incredibly expensive.

Host 1 Yeah, finding it already there makes a huge difference. Okay, before we go, let's do two quick also on this day facts.

Host 3 Let's hear.

Host 1 So in 1715, Dorothea Erxleben was born. She learned medicine at home and became the very first woman in Germany to earn a medical degree.

Host 3 That is amazing

Host 1 And in 1907, French inventor Paul Cornu got his helicopter off the ground. It lifted off for 20 seconds.

Host 3 Wait, how high did it go?

Host 1 Just one foot. Into the air.

Host 2 Hey, every foot counts.

Host 1 It sure does. So what is our final did you know fact for today?

Host 2 Well did you know the floor of that moon crater Cabeus sits at minus 230 degrees Celsius. It's much colder than anywhere on Earth which is exactly why the ice can last there finding that hidden treasure in the freezing dark shows how far we can push the boundaries of discovery.

Host 1 Thanks for tuning in. See you back here tomorrow.