That means that there's a lot of data flowing around the Exploratorium. Each individual computer may not receive or produce much data, but collectively quite a few bits are flying back and forth. If you build a city and want to supply all the houses with water, you install a few very large pipes, or water mains. Each house taps into the water main with a smaller pipe. The water main carries the collective water for the city.
Most data flows through copper wires.
When the flashes of light reach their destination at the far end, they are turned back into electrical signals. We run this fiber between several distribution points within the museum. At each of these distribution points, the optical signal is converted back to an electrical signal and we use standard copper wire to connect to the individual computers. The distribution frames are where everyone connects. A hub is a simple device that will allow many people to attach their computers together.