look at me still talking when there's science to do

(See, I told you: it always works.)

Ross winced, bit his tongue to curb the usual stream of curses that stepping on a mysterious something would usually bring, and picked up the offending object with his toes.
It was a small and impractical looking shoe, in a dashing shade of Pepto-Bismol Pink.
"This is yours, darling." he commented mildly, handing it to the small girl sitting on the floor near the game consoles. "Or, well, Barbie's."
She looked up at him for a moment with the same intense-eyed gaze he saw when he looked in the mirror every morning and nodded, setting her short braids bobbing. "Thank you."
"Try not to leave it where your big brother can kill himself on it, please?" Ross retrieved a soda from the minifridge and sat down at the desk again, picking up the stack of papers he was grading.
They sat in comfortable silence for a while, the shuffle of papers and the tapping of plastic feet on parquet tiles the only sounds.
Claire looked up. "I wanna go to the park." she demanded.
"After I'm done here."
"I wanna go to the park." she insisted.
"Claire, love, I've got to finish this, and then we can go."
Her deep green eyes flashed at him. "I wanna go to the park now!"
As Ross watched, the Barbie that she was holding (by the legs, of course, projectile-style - Claire was never one to play with Barbies the way Mattel intended) seemed to fly towards him in slow-motion -
And then vanished.
Blinking, he ducked under the desk. When he poked his head out again, Barbie was an architectural installation - blank blue eyes staring back at him, up to her waist in drywall.
Ross stared at Barbie, and then at his little sister, and back at Barbie again. She had.
She had timeshifted Barbie.
She was six. Six.
"Would you like something for your headache, darling?" Ross cleared his throat and rummaged through his desk for a bottle of painkiller.