They key can been seen three times throughout the film. First in the scene where time time capsule is opened, a second time on a gold chain being worn by the mom, and a third time at the end of them film when she closes the box.
The 'molecule' can also be seen three times throughout the film to tie each of the three time frames together. Its seen in the young Casey's bedroom in the background on his clothing cabinet. Its seen again in the lab scene with 10 year old Casey on his desk. And then finally a drawing of it is seen on the wall behind the mom when she writes.
Jt Barry has an older sister who pursues acting too.