Excursions in Science!
These gifs come from a 1935 educational film made by GE called Excursions in Science. The company presented some of the science and technology its researchers were developing, along with the era’s state-of-the-art manufacturing processes.
At top, researchers present toothless gears, which are magnetic wheels that spin based on attraction and repulsion at their poles. The display showed off a new alloy that could be magnetized in sections, a significant innovation over iron magnets. The wheel on the left has two poles. The central one has four. The right has six. Since like poles repel, the three wheels created a magnetic gear train when the first was spun.
The bottom left gif shows the concept behind a sorter that used a light-sensitive eye called a phototube to detect dark from bright colors. Here, the machine is programmed to eject black balls as they passed on a rotating disk.
The bottom right gif shows the inspection process being used at the time to ensure lightbulb filament quality. After being manufactured, the filaments passed under an enlarging lens that helped workers sort out those that had uneven coils.