Emmett Brown set up an experiment that involved his many clocks in his garage, and then left his equipment on all week while he worked on completing the DeLorean time machine at another location.

The morning of October 25, 1985, as Marty McFly picked up the phone to talk to Doc, all of his clocks chimed 8:00 a.m., however this proved at that instance that they were all 25 minutes slow and that the time was actually 8:25 a.m. Marty didn't notice there was only one clock that had the correct time, resting sideways on the floor, close to a box of plutonium under the bed, which he also didn't notice. Marty responded to Doc that he was late for school and headed out the door.

Behind the scenes

As for how exactly this experiment was related to his work with time travel is unclear.

Appearances

• Back to the Future