The science/tech behind skiing?

Longer means more stability as the speed increases, weight makes a ski quit vibrating, this is basic physics. Other factors being equal.

Side cut radius will determine the natural turn length of a ski, the shorter the radius, the shorter the turn. The sharpeness of the edges will allow a ski to hold its line in harder snow. The responsive ski is dependent on the material of construction among other things. When all of these factors are blended properly you have a good or a great ski, mixed wrong, you have a dud. This is just a very rough outline of the design and the how and why with everything else staying the same it holds true. When different materials are used things change. A single piece wood ski is replaced by a laminated ski and the length got shorter, aluminum was added and the ski got thinner and softer, fiberglass is added and the ski is now wider and softer and shorter. Hope this helped.