C̶o̶d̶a̶ Codex Equestria: Scientific Pony T̶a̶i̶l̶s̶ Tales

by Pineta

Blue Sky Thinking

Vectors by HerrMyrddin and tamalesyatole.

It was a beautiful sunny day. The sky above Ponyville was a perfect photogenic image of fluffy white clouds against a blue background, with a touch of brighter colouring where a pegasus tail or two was visible hanging out of a cloud.

Rainbow Dash stretched out her wings and legs, enjoying the feeling of smug satisfaction which comes when resting after a vigorous afternoon of showing off your top stunts to your fans. Next to her Scootaloo lay in the soft white fluff, enjoying the feeling of serene happiness which comes when you're lying next to the most awesome pony in the world who has taken you under her wing.

“The wispy ones are the cirrus clouds,” said Rainbow, staring up into the sky. “They're real high, and can move fast. It's fun to chase them. Then there are the cumulonimbus clouds. They're good to hide in, and make lightning—perfect for playing pranks. And there are stratocumulus clouds, which make good race markers.”

Scootaloo listened happily while Dash preened her feathers.

“Rainbow Dash,” she said, staring upwards with a thoughtful expression. “Why is the sky blue?”

Dash stopped working on her wings and paused, unsure how to answer this.

“Because it's an awesome colour for a sky,” she said eventually.

“Yes, but why?”

Dash didn't know. Why didn't they teach this stuff at flight school? Slightly annoyed, she rubbed Scootaloo's head with a hoof.

“Hey, that's an egghead question!”

“Don't you know?”

“Of course I know.” She paused and Scootaloo turned to face her waiting for the answer. “At least, I mean, I know how I can find out. You see, being awesome isn't about knowing everything—that's what eggheads do—it's about knowing enough to do what you want, and having friends who can tell you everything else if you need it. So if I want to know why the sky is blue I just have to go and ask Twilight.” She lay back in the cloud, pleased that she had managed to think up a good response.

“Can we go and ask Twilight?”

Dash lifted her head off her cloud pillow and stared into Scootaloo's bright-eyed, inquisitive face.

“You really want to know, don't you?”

“Yes.”

“Come on.”

She lifted the little filly onto her back, and jumped off the cloud.

Five minutes later they found Twilight Sparkle, busy cataloguing the new books inside the library. She had just devised a new classification system, in which each book was labelled by a coloured alphanumerical code on the spine to identify its subject matter, language and author, and was now enjoying relabelling her entire collection.

“Hey Twi,” said Rainbow. “Tell us why the sky is blue.”

Twilight grinned at the unexpected pleasure of an afternoon science test.

“It's due to the wavelength dependence of the scattering of light by the nitrogen, oxygen and other molecules in the atmosphere. Shorter wavelengths—which make up blue light—are scattered more than the longer wavelengths—which make up red light. Hence the sky looks blue. Except when we look at a sunset, when we see the red-orange light transmitted through a long distance of air.”

Scootaloo whispered to Rainbow Dash, “What does that mean?”

“Err...” Dash looked around the library hall looking for help. She caught sight of Pinkie Pie sitting on a cushion reading a comic. “Just a moment...” She flew across to her and whispered into a pink ear, “What the hay did that mean?”

“Duh,” replied Pinkie, bouncing across the room to join Twilight and Scootaloo. “You shine every colour onto the sky, and the air kicks the blue all over the place and lets the red through. You just need a whole sky-full of air to see it. It also works with water and flour, milk or coffee cream. It probably also works with chalk, but I've not tried that, and cream tastes better than chalk anyway.”

“Err, what?”

To illustrate the principle Pinkie donned a chef's hat and apron, produced a large glass bowl of water from behind a bookshelf, and tipped in a bag of flour. She mixed this vigorously, sending droplets of flour and water flying around the room. (Twilight quickly cast a spell to shield her books with a protective force field.) Then throwing aside her apron and hat, she strapped a headlamp around her pink mane, jumped over to pull the curtains across the window, plunging the room into darkness. She then shone her light into the water. A bluish-white colour was reflected back.

“Oh,” said Scootaloo, “now I see.”

“And from the other side...” Pinkie jumped around the bowl to the side opposite Scootaloo and crouched down to shine the light through the water so the light Scootaloo saw was the orange colour of her coat. “Sunset!”

“That's not quite the same thing,” objected Twilight. “Flour particles are much bigger than air molecules, so the light is scattered by a different process. It just happens to give the same result.”

“That's good enough for me,” said Dash.

“And me,” agreed Scootaloo.

“Where did you learn that trick Pinkie?” said Dash.

“Baby-sit the Cake twins and you learn everything you need to know about flour and water.”

Author's Note:

Further Reading: Why is the Sky Blue?

Comments

[AppleTank]

heh, cute.
I'm marking this to my sci-fi category. For Science

[Walabio]

¡A new story from Pineta!

[Dinoguy1000]

Relevant xkcd (this one is too!)