Science at Bedtime

"Daddy? How do you make water?"

"You mean, what is it made of?"

"Yeah, what's water made of?"

"Hydrogen and oxygen."

"Oh. And what's hydrogen and oxygen?"

"They're chemical elements."

"So, when we drink water, we're drinking chemicals?"

"Well, yeah. In a sense, everything is chemicals. Water's a chemical, air is made of chemicals. "

"What about, like, wood?"


"What?!?! Is everything chemicals?"

"Pretty much, yeah."

"What about lights?"

"Light isn't a chemical, but the things that make light are made out of chemicals."

"Yeah, like, the Sun is fire, and it makes light, but is the light fire? No, it's not."

"Right. Well, the Sun isn't really fire. Actually, it's mostly hydrogen. There's so much of it, and it's squeezed down tight by gravity, so it starts to stick together and make helium. When it does, it gets really hot, and makes light."

"So, like, what made, like... space, and... everything?"

"You mean, where did it come from?"

"Yeah, where did space come from?"

"Well, scientists know that a long time ago, a little less than fourteen billion years ago, the entire universe was just a tiny, tiny little point. And then... poof it blew up, and started expanding. It's called the Big Bang."

"What?!?!? The Big Bang?"

"Yep. Before that, there wasn't any space, and there wasn't any time. Space and time started then, really, really small, and it was really hot."

"So, like, everything was all white and light and stuff?"

"In a manner of speaking. It was super hot, though, way hotter than the inside of the Sun. It's been cooling off and spreading out ever since."

"Is that why there's no air in space?"


"Yeah because everything spread out, so there's no air in space. Except there's air on Earth, but Earth is in space, and there's no air in space, so why is there air on Earth?"

"Well, the Earth is really big, right? So it has a lot of gravity. And just like gravity holds you down to the ground, gravity holds the air down to the Earth. If Earth were a smaller planet, like Mercury, or the Moon, it wouldn't be able to hold onto the air. Which is why there's no air on the Moon."

"Oh. Okay."

"You know, you remember that space show we watched?"


"There was another one of those, that we have on the tv, and it's all about how animals evolved and that sort of thing. And there will be more, and I'm pretty sure there'll be one all about the Big Bang, and where everything came from."


"Really. And when there is, we can watch it, and you can learn more about it. Would you like that?"


"Okay, then. Until then, though, do you think you can go to sleep?"

"I guess so."

"Good. Do that. Sleep well, I love you."

"I love you, too, Daddy."


(The "featured image" up top is from Monday night after SteelyKid's taekwondo class. They had a belt test last week (she'll most likely be moving up to yellow), and it seems they spend the next class after a belt test doing board-breaking as a reward. The board in question is half-inch pine, a little thinner than the ones we use for the board-breaking lab in intro mechanics, so I know it's not all that difficult to break, but she was so fired up about breaking it with a punch, it was ridiculously cute...)

More like this

"…so I know it’s not all that difficult to break, but she was so fired up about breaking it with a punch…"

Hey dude come on, she's just a little kid!

Hydrogen and oxygen are chemicals? I thought they were elements...

Or am I being `picky'?

Hint: Don't forget that kids thrive on and are comforted by repetition, its why thy can stand listening to a purple dinosaurs fifty times in one day, so keep Cosmos on the player. Osmosis and repetition will install the ideas painlessly on young brain cells.


Hydrogen and Oxygen are most certainly chemicals. And elements. And atoms. And, in their naturally occurring states, also molecules.

By William Hendrixson (not verified) on 19 Mar 2014 #permalink

I shudder to think how that conversation would have progressed with a parent who was neither a scientist nor science literate.

By Bruce W. Fowlet (not verified) on 20 Mar 2014 #permalink