English: Demonstration inclined plane apparatus, used in science education probably around the early 20th century, on display in the Schulhistorische Sammlung (School Historical Museum), Bremerhaven, Germany. The slanting metal track serves as an inclined plane. The small brass wheel on the track (left) with the large weight hanging from it serves as a load, which is pulled up the plane by the cord attached to the small weight (right). Since the larger weight can be pulled up the plane by the smaller weight the inclined plane demonstrates mechanical advantage. The angle of the track is adjustable, to change the mechanical advantage.