- "It was Mayor Thomas' idea. He had visions of Hill Valley becoming a magnet for big investors in the technology sector! But the venture followed after the third year when the Influenza exhibit leaked into the concession stand."
- —Alternate Doc giving the explanation about the expo
The Hill Valley Science Exposition was an event that Mayor Jack Thomas came up in 1931 with to attract investors in the technology field. It was held annually until 1933 at the Hill Valley High School.
Arthur McFly was in charge of handling the money, employment and termination of employees, and contestant registration. Trixie Trotter was given the position of Techne, The Muse of Progress to inspire contestants and present the award to the one who wins. Cue Ball was given the job of making deliveries to the high school. Ernest Philpott (also a contestant) overlooked everything outside the day before the inventions were displayed.
In the front of the school were two displays of Hill Valley during October 12. One being Hill Valley of the Past, and the other being Hill Valley of the Future, with a prediction of how the town would look in 1981.
The exhibits entered were up by the next day. Arthur continued with the sign ups, Trixie handed out the tickets to those attending and Cue Ball looked out for trouble.
October 13 contestant roster
- Dr. Lev Grossman (wasn't seen, nor was his entry specified.)
- Dr. Ernest Philpott
- Dt. Danny Parker (was occupied with Edna Strickland, and unable to take his turn).
- Mr. Emmett Brown
- The Electrokinetic levitator - Built by Emmett Brown, which was a modified version of his Rocket-powered car, with the static accumulator as the primary source of energy. The exhibit failed though, despite a promising beginning. Brown himself stated that he was banned from the Expo for the next 50 years, in which he would not be able to return until 1981.
- Professor Fringle's Algae Cakes - Ernest Philpott hands out free algae cakes to those at the Expo.
- Continuuophone - Also known as a Theremin Booth which a person could make music with their movement.
- Enlightenment Under the Sea - Presented by the famous diver Jacques Douteux, in which a person could go underwater in a device called the Bathysphere. A ticket was required for this exhibit.
- The Chronometric Clock - Which Marty found difficult to tell the time with.
- Future Furnishings - A predicted house of the future which contained a fully stocked entertainment center, a privacy phone helmet and a fruit basket compartment that comes out of the ceiling. A ticket was required for this exhibit.
- Atlas House of Glass - The outer walls were made of glass, with sliding doors that would double as a wall. A wall made out of wood doubled as a passage into Future Furnishings. A ticket was required for this exhibit.
- Phone Booth of the Future - A phone booth allowing for privacy and for calls to be handle leaving the caller with free hands. This particular booth could only receive calls.
- Picture radio - Though it looked more like a radio with a moving picture, it was similar to the television.
- The Future of Law Enforcement - Danny Parker presented devices which were later suppose to be available to police officers in the future, including a Plant recorder, The Amazing Inebriomatic and The Elektro-Pacifier.
The expo is held. Nothing of significance was noted.
- Back to the Future: The Game
- Back to the Future: The Game - Episode 1: It's About Time (First mentioned)
- Back to the Future: The Game - Episode 2: Get Tannen! (Mentioned only)
- Back to the Future: The Game - Episode 3: Citizen Brown (Mentioned only)
- Back to the Future: The Game - Episode 4: Double Visions (Mentioned only)
- Back to the Future: The Game - Episode 5: OUTATIME (First appearance)