In Vault 106's Living Quarters, on a steel shelf, east most room on the top floor after following a single path, with two doors.
The exact location from the entrance of the vault: Go north through the vault door, then right (east) through another open door. Once through the door, it will open into a long hallway. Continue down this hallway as it goes east, north, and west until it ends at the entrance door to the Living Quarters. Enter the Living Quarters and take an immediate left (east) across the small bridge and then right (south) once over the bridge. Go south a short distance until you dead-end at a giant white crate. From here, go east through the open door, then south through another open door and follow the hallway as it hooks left (east) until you get to the room at the end. The Bobblehead is straight ahead on a bookshelf at the back of the room.
Obtaining Bobblehead Science