Work Text:
One thing Donald Davenport hadn’t counted on when he decided to adopt (well, steal) Adam, Bree and Chase was how often he would have to break up fights.
Sure, they were siblings which meant fighting was only natural, but today’s argument might have been the most unexpected one so far.
It started off, as so many other times before, with Donald coming down the elevator and right into a shouting match.
“–not true!” Bree screeched, her little voice shrill.
“It’s science!” Chase argued just as loudly back.
A groan from Adam. “Guys, can we stop talking boring stuff and just play? I wanna toss someone!”
“You’re being stupid, Chase!”
“What do you mean stupid, you’re the–”
And that was Donald’s cue to step in. “Hey!” The three kids immediately snapped their heads his way as he walked across the lab to them. “What did I tell you about the yelling?”
They all looked down, mumbling a unison, “Sorry, Mr. Davenport,” and wow, it still felt weird being called that. For most people – including himself – Mr. Davenport was his dad, not him. While he definitely could get used to it, for now hearing it gave him major cognitive dissonance.
Heck, two years ago, he was still living with his parents.
Two years ago, his version of a well-cooked meal was microwaved pizza (still was, if he was being honest).
Two years ago, he had a brother who was– well, not evil.
He pushed away the thought to stare down at the kids in what he hoped was a stern manner. “What are you fighting about this time?”
“Chase started it!” Bree said, pointing.
“I didn’t–”
“Yes you did– ”
“I just wanted to play bionic tag,” Adam said mournfully.
“Okay, okay,” Donald held his hands up and the kids quieted down again. “Chase?”
“We were playing bionic tag,” Chase started, straightening to his full height of 3’5”. “And I jus’ was thinking about what you said about Einstein, about how gravity bends space?”
Donald felt his eyebrows rise. “Okay…?”
“And I was thinking, gravity is like ack– acklese–”
“Acceleration?”
“Yeah, that. So when Bree does super speed, that has to mean she bends space too? So I said that and–”
“And it’s stupid," Bree cut in with the level of irritation only a six-year-old could muster, “because I run and the lab doesn’t go bendy like–”
“A donut!” Adam yelled.
“Yeah, a donut!”
Donald blinked, looking between the three of them. It was times like these the bionic part of the bionic children shone through. Because Chase may look like a regular five-year-old and still slurred his ‘s’-es… but he spoke with the vocabulary and, well, intelligence of a kid far older. It would be creepy if Donald didn’t find it so fascinating. What other five-year-old could understand the basic concept of relativity?!
He cleared his throat. “No, Chase is actually right. Your powers bend space.”
Chase’s entire face lit up. “Really?”
“Yes. But your powers don’t just bend space, Bree, they also bend time.”
Bree was not sold. “How can you bend time? Time isn’t a jump rope!”
“Time bends because space bends, stupid!”
“Chase, ” Donald warned, but without real heat because Chase was bouncing up and down, beaming, and well, Donald could relate to the glee of being right.
But that brought him to his next problem: How was he to explain spacetime and time dilation in a way three elementary schoolers would understand?
“Okay, it’s like this,” he finally said, facing Bree. “You know how the room goes a bit blurry when you super-speed?”
Bree crossed her arms, but nodded.
“That’s not just because your eyes don’t have time to see everything; you’re actually running so fast the room gets a little bit smaller. Only for you, Bree,” he added when Adam raised his hand, “for everyone else the room is the same size.”
That wasn’t entirely true, since everyone’s movements dilates spacetime ever so slightly, but technicalities. He was trying to perform a teacher’s miracle here!
“And here’s the weird thing,” he continued, gesturing, “when you make the room smaller, time also gets smaller. That means that when you super-speed, time moves slower for you than for everyone else. For example, what is five seconds for you might actually be ten seconds for everyone around you.”
Silence filled the lab as the three kids gaped back at him. If it was in confusion or awe he wasn’t entirely sure. He hoped it was awe.
“Wait.” Adam frowned, the cogs in his head visibly turning. “So Bree’s a witch?”
“I’m not a witch!”
“More like a time traveler,” Chase added, somewhat jealously. “Like that old movie you made us watch, Mr. Davenport.”
Adam grinned. “Oh yeah, the one with that old Doctor Davenport guy! Who put his dog in the time machine car.” He sighed wistfully. “I want a dog. I’d name him Fluff’n’stuff.”
“Okay, first of all, Back to the future is not old. Secondly, Doc is nowhere near my genius. 88 miles per hour?” Donald scoffed. “That’s obviously nowhere near light speed. And my hair is so much better than–” He paused, realising he was losing the kids’ interest. “But yes, technically Bree’s a time traveller. But she can only travel forward in time and even then, it’s only by seconds. Over her lifetime, it might add up to a few minutes at most! But if I managed to upgrade her chip so that she was running almost at light speed…”
A prickle of elation went through him at the thought. If he considered the average time per week Bree spent super-speeding and used the Lorentz factor to calculate the maximum amount of time dilation created, that would mean…
“Let me get the whiteboard!”
Chase let out an excited “Yes!!” at the same time as Adam moaned “Nooo! Not more school!”
Donald was already in the supply closet, kicking stuffed animals and pool noodles out of the way as he wheeled the whiteboard to the middle of the lab. For a while he had used his prototype holographic whiteboard, but after that one time when Adam’s heat vision glitched out so badly he had shot the holo-projector and caused a two-day power outage for the entire house, Donald had deemed it safer to stick to old-fashioned school equipment. At least a few burned holes and bionic boogers didn’t stop it from working!
Grabbing a red marker, Donald scribbled out a formula at the top of the board.
“So this formula,” he circled it a few times, “describes how time changes for an object or subject when it moves. In our case, it describes how much Bree’s time changes from our time when she super-speeds.
“So t 0, which we’re trying to find out,” he wrote the descriptions down as he talked, “describes time dilation, or the difference between Bree’s time and our time.
“t describes how often Bree runs at super speed during a week, v what speed Bree usually runs at…
“And finally, c is the speed of light. Which is…?”
He turned to his audience, finding exactly one hand raised. Adam had already lost interest, currently trying to make a scarf for a stuffed duck with one of the pool noodles. Bree however, while still crossing her arms and giving him one of her judgy faces, had actually sat down next to Chase and appeared to be listening. Expecting her to answer one of his questions would be pushing his luck though, and so he turned to the final kid in the room.
“Three hundred million meters a second!” Chase yelled proudly, with extra spit on the ‘th’-sound.
“Exactly. So c equals 300 000 000. And if we say Bree runs at super speed about one and a half hours a week, that’s– Give me a second… 5400 seconds a week.” Assuming she ran at a constant speed of course, which she definitely didn’t. But getting acceleration involved would make things way too complicated. “And,” Donald continued, “if I upgraded her super speed so she’s running at almost light speed, let’s say 290 000 000 meters per second… we get a formula that looks like this!”
“Awesome!” Adam yelled, and Donald looked over with a grin, ready to say that yes Adam, I am awesome and so is physics … to find his oldest kid had ripped the head off the duck and was pulling out the stuffing. “There’s cotton candy in here!”
“Adam, don’t–”
“Eurgh, gross!"
“–eat the stuffing.” Donald pinched the bridge of his nose. “Anyway,” he said, ignoring the sounds of a guillotined duck being hit by a pool noodle in the background, “if we calculate all this together,” he pulled out his handy pocket calculator, “we get that t0 is 4017.39. So for every week Bree super-speeds, time moves about 4000 seconds slower for her than for everyone else. And if we add that up across an entire year…” Donald paused. “Hey,” he gestured between Bree and Chase, “how far is it between your birthdays?”
This time it was Bree who answered, a smug smile on her face. “Eleven months.”
“Nuh-uh!” Chase stood up. “It’s 321 days – ten and a half months!”
“I’m still older and you’re still a baby.”
“Am not!”
“Am too!”
Donald ignored the squabbling, too focused on doing calculations. 321 days, multiplied by 24 hours, multiplied by 3600 seconds… that would make it 19 958 400 seconds between their birthdays… and if he multiplied 4017.39 with 52 weeks, that meant Bree’s time dilation would be 208 904.28 seconds per year, which meant…
He burst out laughing.
“What’s so funny, Mr Davenport?” Bree said.
“Yeah, what’s funny?” Chase echoed from the floor beneath her, clearly having lost a wrestling match.
“Just look at this,” Donald did not giggle as he pointed to his final calculation on the board; it was a very manly chuckle, thank you, “there’s 19 958 400 seconds between your birthdays, right, and if Bree dilates time by 208 904.28 seconds per year, that means…!”
Bree and Chase stared blankly between him and the whiteboard, and Donald sighed inwardly.
“It means that in 95 and a half years’ time, Chase will be older than Bree!”
Maybe Donald should have realised that was not the best thing to tell three elementary schoolers with premature prefrontal cortexes, a growing sibling rivalry and glitchy superpowers, but, well. He was a genius inventor and an expert in biochemical engineering, not a children’s psychologist. Sue him.
“Wait…” Bree clambered off Chase with growing horror on her face. “Mr Davenport, you mean–”
“He means if you use your powers too much, I’m gonna be your big brother!” Chase filled in gleefully. “That’s so cool!”
Bree screamed.
“No, wait, that’s not–” Donald held up his hands. “That would only happen if I upgraded your super speed to near light speed–”
“We’re gonna do upgrades tomorrow!” Chase yelled.
“Yes, but not–” He winced as Bree screamed even louder. God, how could such a tiny person fit so much voice inside her?
“Chase is gonna be my big brother?!” Adam’s panicked voice cut through the chaos, and great, of all the times for him to actually start half-listening to Donald’s lectures it had to be now.
“No Adam, you don’t even have super speed–”
He was drowned out by two screaming kids and one shrieking with laughter.
:::
Adam forgot the whole thing the next day, but it took three days before Donald could get Bree to use her super speed again and a full two weeks before he could convince her to let him do upgrades on her chip (mostly by convincing Chase to stop teasing her about it).
Next time the kids asked about the physics behind their bionics, maybe Donald should just tell them their bionic chips were magic. At least that would do less damage to his eardrums.